Name: experimental procedure for warm spinning of cast aluminum components
Uploaded: 2017-02-01T15:00:00.000+00:00
Duration: 7 min 36 s
Description: Watch this Scientific Journal Video about Experimental Procedure for Warm Spinning of Cast Aluminum Components at JoVE.com

<p class="jove_content"> 저자는 기술 지원을 로스 MCLEOD, 데이비드 토록, 유원상 김 칼 잉에게 감사의 말씀을 전합니다. MJ 로이는 연구 활동 상을 통해 재정 지원을 위해 박사 교육 및 리오 틴토 알칸에 대한 환경 센터 까다로운에 대한 자료를 통해 EPSRC (EP / L01680X / 1)의 지원을 인정하고 싶습니다. </p>

<p class="jove_title"> 시험을 형성 1. 공작물 준비 </p><ol><li> 외경 최대한 주조 표면을 유지하면서, 이러한 내경 런아웃 0.2 mm임을 맨드릴 크기로 가공 등 캐스트 공작물 획득. <br /> 주 : 블랭크는 전체 크기 휠 주물로부터 인출하는 경우, 가공 작업을 맨드릴에 공작물을 고정하는데 이용 될 수있는 기능을 제공하면서, 모든 허브를 제거한 부분 스포크 요구된다. 이에 내장 된 플랜지의 제거를 포함한다. </li><li> 135 ° C까지의 전체 워크 수신 열차 폐 코팅 프로그램을 준비하기 위해 한 시간 동안 노 탈지제 및 장소 공작물을 청소할 수 입관로를 예열. </li><li> 급속 노로부터 공작물을 제거하고 코팅 지그에 배치했다. 자동차 형 도료 분무기를 사용하여, 내경 단열 다이 코팅의 얇은 층을 적용한다. <br /> 이 코팅은 윤활을 제공하고 열 전달을 감소 : 주성형 작업 중에 맨드릴. </li></ol><p class="jove_title"> 2. 공구 준비 </p><ol><li> 젖은 천으로 맨드릴 표면을 닦으십시오. 맨드릴이 형성 길이를 따라 다이얼 게이지 표시를 사용하여 &lt;0.5 mm의 총 회전 진동이 있는지 확인하십시오. 심 압대 판에 종사하는 라이브 툴링 센터와이 평가합니다. 토크 렌치를 사용하여 클램프 어셈블리에 사람들을 제외하고 모든 체결 학년 12.9 볼트에 대한 규정 토크 값으로 조여 있는지 확인 (뉴 멕시코 : M8 - 40, M12 - 135, M16 - 340). </li><li> 먼저 가스 공급 솔레노이드에 전력을 공급하고 라이터 불꽃 부싯돌과 토치의 점화에 의해 예열 시스템을 시작. 10 분은 횃불 / 호스에 수집 된 응축수를 배출하기위한 예열 시스템을 실행합니다. 가스 공급 솔레노이드를 비활성화하여 끈다. </li><li> 분당 20 회전에 맨드릴을 켜는 동안 건조 600 / P1200 그릿 실리콘 카바이드 종이 맨드릴에 느슨한 / 산화 코팅 층을 제거수 (rpm). </li><li> 전원 보드상의 데이터 취득 모듈 및 라이브 센터 종사와 맨드릴 표면에 매립 된 열전쌍은 200 °의 C를 판독 할 때까지 예비 가열 시스템을 실행. </li><li> 라이브 공구 중심이 결합하여 회전 공구를 자동차 형 도료 분무기 가볍게 코트 수계 단조 윤활제 맨드릴 표면에 사용 가능하면, 주위 온도로 냉각. </li><li> 렌치 롤러 스탠드 <strong>(그림 3)에</strong> 잼 너트 어셈블리를 풉니 다. TOOLMAKER의 각도기를 사용하여 롤러 어셈블리에 접근 또는 공격의 각도를 설정하고 내부 및 외부 너트 (M35 - 750 ㎚)를 모두 조입니다. </li><li> 제 클램프 브래킷 소자 (2)를 연결하는 M12 쇼울더 볼트 결합에 의해 3 클램프 어셈블리 <strong>(도 4)를</strong> 조립한다. 부드럽게 클램프 브래킷에 대해 실행 <strong>그림 4</strong> 요소 (2)를 방지 할 수있는 열 왜곡을 검사합니다. 가볍게이야, 그들이 자유롭게 이동하는지 확인건조 320 / P400 그릿 실리콘 카바이드 종이 접촉면을 AND 연산. 필요에 따라 천 고온 몰리브덴 계 윤활제의 박층을 적용한다. </li></ol><p class="jove_title"> 3. 성형 작업 </p><ol><li> 롤러 도구, 완전히 떨어져 주축으로 맨드릴에서 서 맨드릴의 명확하게하기 위해 심 압대와 중심을 이동 이동합니다. 수동으로도 참여를 보장 맨드릴에 공작물을 밀어 넣습니다. <br /> 주 : 공백이 명목상 축 대칭있는 바와 같이, 더 바람직한 방향이 없습니다. </li><li> 테이퍼 다이 핀을 결합하고 손 클램프 블록으로 맨드릴을 통해 실행 M16 볼트를 조여 맨드릴 상에 클램프를 조립합니다. 심지어 압력이 50 Nm의 설정 공압 임팩트 렌치 다음, 체결 수동 회전에 의해 적용되는이 있는지 확인하십시오. </li><li> 가열 시스템을 시작하고 바로 20 rpm으로 회전하는 맨드릴을 시작합니다. 클램프가 완화 될 때까지 열을 적용하십시오. 고려 된 방법의 경우,이 AP는3 분을 근접하여. <br /> 참고 :이 시간으로 인해 워크 / 맨드릴 비품의 미묘한 차이로 각각의 작업 물이 약간 달라집니다. </li><li> 가열 시스템 진화 한 제 클램프 임팩트 렌치 액세스되도록 상기 맨드릴의 회전을 멈춘다. 30 초 이내에, 충격 또는 수동 공구 모든 클램프를 조여 리드 타입 열전쌍 프로브 형성 영역의 길이를 따라 3 위치에 피 가공물의 표면 온도를 기록한다. </li><li> 워크까지 단계를 반복 3.4 적절한 형성 온도에; 최소한, A356 350 ° C를. 200 Nm의 설정 임팩트 렌치 클램프의 최종 긴축을 수행합니다. </li><li> 축 방향 및 반경 방향으로 롤러를 이동 (약. 2-5 공작물 표면에서 mm)의 형성 위치에, 그리고 체결 마지막 클램프 <em>(즉,</em> 단계 3.4)을 수행합니다. </li><li> 의도 형성 속도에 선반의 회전 속도를 증가하고 상기 가열 시스템에 롤러 결합미리 설정된 편으로 깊이와 공작물의 길이를 따라 축 방향으로 롤러를 이동 나사못 공급 활성화. <br /> 참고 : 본 형상은, 합리적인 결과가 0.21 mm / 회전의 축 이동과 281 rpm에서 달성했다. </li><li> 변형의 수준을 높이기 위해 필요한 단계를 반복합니다 3.7. 각 패스의 형성 후, 온도가 맨드릴을 정지하고, 단계 3.4에서 사용되는 것과 같은 리드 타입 열전쌍 프로브를 사용하여 최적의 성형 온도 이하로 떨어지지 않는 것을 보장한다. 최적의 형성 온도를 떨어 경우, 반복 3.4 및 3.5 재가열하는 단계를 반복합니다. <br /> 주 : 재가열은 그러나 잠재적으로 공작물을 억제하는 클램프 시스템의 능력의 범위에 도달하는 비용으로 이용 될 수있다. </li></ol><p class="jove_title"> 4. 포스트 성형 작업 </p><ol><li> 변형의 원하는 레벨을 획득 한 후, 가열 시스템을 정지하고, 모든 클램프를 취소하고, CLE를 얻기 위해 심 압대를 분리워크 제거를위한 arance. </li><li> 조심스럽게 맨드릴에서 분리 놋쇠 조각으로 공작물을 누릅니다. 이 효과가 입증되면, 가열 시스템을 재 참여 조심스럽게 빈 분리형 때까지 눌러 20 rpm에서 맨드릴을 회전합니다. </li><li> 이러한 집게 또는 무겁게 절연 장갑 등의 적절한 조작 도구를 사용하거나 60 ° C에서 물에 공작물을 해소하는 것은 더 노화를 방지 또는 잔류 응력 / 왜곡을 최소화하기 위해 공기 냉각에두고있다. </li></ol>

<ol>
	<li>Wong, C., Dean, T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+review+of+spinning,+shear+forming+and+flow+forming+processes.">A review of spinning, shear forming and flow forming processes.</a> <em style='font-style: italic'>Int. J Mach Tool Manu</em>. <b>43</b> (14), 1419-1435 (2003).</li><li>Music, O., Allwood, J. M., Kawai, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+review+of+the+mechanics+of+metal+spinning.">A review of the mechanics of metal spinning.</a> <em style='font-style: italic'>J Mater Process Tech</em>. <b>210</b> (1), 3-23 (2010).</li><li>Razani, N. A., Jalali Aghchai, A., Mollaei Dariani, B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Flow-forming+optimization+based+on+hardness+of+flow-formed+AISI321+tube+using+response+surface+method.">Flow-forming optimization based on hardness of flow-formed AISI321 tube using response surface method.</a> <em style='font-style: italic'>Int J Adv Manuf Tech</em>. <b>70</b> (5), 1463-1471 (2014).</li><li>Abedini, A., Rash Ahmadi, S., Doniavi, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Roughness+optimization+of+flow-formed+tubes+using+the+Taguchi+method.">Roughness optimization of flow-formed tubes using the Taguchi method.</a> <em style='font-style: italic'>Int J Adv Manuf Tech</em>. <b>72</b> (5), 1009-1019 (2014).</li><li>Davidson, M. J., Balasubramanian, K., Tagore, G. R. N. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Experimental+investigation+on+flow-forming+of+AA6061+alloy-A+Taguchi+approach.">Experimental investigation on flow-forming of AA6061 alloy-A Taguchi approach.</a> <em style='font-style: italic'>J Mater Process Tech</em>. <b>200</b> (1-3), 283-287 (2008).</li><li>Cheng, Y. C., Lin, C. K., Tan, A. H., Lin, J. C., Lee, S. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Effect+of+Spinning+Deformation+Processing+on+the+Wear+and+Corrosion+Properties+of+Al-7Si-0.3Mg+Alloys.">Effect of Spinning Deformation Processing on the Wear and Corrosion Properties of Al-7Si-0.3Mg Alloys.</a> <em style='font-style: italic'>Mater Manuf Process</em>. <b>25</b> (7), 689-695 (2010).</li><li>Mori, K., Ishiguro, M., Isomura, Y. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Hot+shear+spinning+of+cast+aluminium+alloy+parts.">Hot shear spinning of cast aluminium alloy parts.</a> <em style='font-style: italic'>J Mater Process Tech</em>. <b>209</b> (7), 3621-3627 (2009).</li><li>Roy, M. J., Maijer, D. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Response+of+A356+to+warm+rotary+forming+and+subsequent+T6+heat+treatment.">Response of A356 to warm rotary forming and subsequent T6 heat treatment.</a> <em style='font-style: italic'>Mat Sci Eng A-Struct</em>. <b>611</b>, 223-233 (2014).</li><li>Roy, M. J., Maijer, D. M., Dancoine, L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Constitutive+behavior+of+as-cast+A356.">Constitutive behavior of as-cast A356.</a> <em style='font-style: italic'>Mat Sci Eng A-Struct</em>. <b>548</b>, 195-205 (2012).</li><li>Molladavoudi, H. R., Djavanroodi, F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Experimental+study+of+thickness+reduction+effects+on+mechanical+properties+and+spinning+accuracy+of+aluminum+7075-O,+during+flow+forming.">Experimental study of thickness reduction effects on mechanical properties and spinning accuracy of aluminum 7075-O, during flow forming.</a> <em style='font-style: italic'>Int J Adv Manuf Tech</em>. <b>52</b> (9), 949-957 (2011).</li><li>Smolenicki, D., Boos, J., Kuster, F., Roelofs, H., Wyen, C. F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=In-process+measurement+of+friction+coefficient+in+orthogonal+cutting.">In-process measurement of friction coefficient in orthogonal cutting.</a> <em style='font-style: italic'>CIRP Ann-Manuf Techn</em>. <b>63</b> (1), 97-100 (2014).</li><li>Xu, W., Zhao, X., Ma, H., Shan, D., Lin, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Influence+of+roller+distribution+modes+on+spinning+force+during+tube+spinning.">Influence of roller distribution modes on spinning force during tube spinning.</a> <em style='font-style: italic'>Int J Mech Sci</em>. <b>113</b>, 10-25 (2016).</li><li>Roy, M. J., Maijer, D. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Analysis+and+modelling+of+a+rotary+forming+process+for+cast+aluminium+alloy+A356.">Analysis and modelling of a rotary forming process for cast aluminium alloy A356.</a> <em style='font-style: italic'>J Mater Process Tech</em>. <b>226</b>, 188-204 (2015).</li><li>Lu, P., Zhang, Y. K., Ma, F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Finite+element+analysis+on+multi-step+rolling+process+and+controlling+quality+defect+for+steel+wheel+rim.">Finite element analysis on multi-step rolling process and controlling quality defect for steel wheel rim.</a> <em style='font-style: italic'>Adv Mech Eng</em>. <b>7</b> (7), 1-11 (2015).</li></ol>

<p class="jove_content"> 대표적인 결과는 사용 된 프로토콜 및 장치가 고온에서 알루미늄 주물을 형성 할 하이라이트 위에서 제시하고 휠을 형성하는 흐름의 처리 윈도우를 결정하기위한 플랫폼을 제공하고있다. 시연이 기술은, 봉투를 형성 모두 형성 무형의 물질이 치료 <sup class="xref">8</sup> 열 응답 방법 등의 측면을 탐구하는 데 사용할 수 있습니다. 그러나,이 장치에 현재의 처리 프로토콜에 개선의 여지가있다. </p><p class="jove_content"> 공정 조건에 대한 중요한 정보를 제공 할 것이다 롤러에 부하 및 마찰 계수를 형성하는 측정하는 프로세스 모델 개발, 기계 공구 동력계 및 tribometers <sup class="xref">(11)를</sup> <sup>포함,</sup> <sup class="xref">12을</sup> 가속화 할 상기 계측에 관한. 이 직교 가공 연구에 널리 사용되는 계측 기술이며, 수쉽게 현재 시스템에서 구현 될 수있다. 이러한 부가 계측 정확하게 모델링 노력 <sup class="xref"><sup>13,</sup></sup> <sup class="xref">14로</sup> 확인하고이 과정에서 증가 산업 관심을 지원하기 위해 유용한 데이터를 제공한다. 효과적으로 처리 중에 블랭크의 온도의 전개를 캡처하기 위해, 비접촉 측정 방법이 바람직하다. 그러나, 일반적인 적외선 - 기반 기술은 처리 중에 표면 변화 알루미늄의 저 방사율 의해 어떻게 방해된다. 이것은 설명 프로토콜 달성 일반적인 열 반응을 캡처하기 위해 사용 된 비어 시운전 계측 및 공작물 맨드릴 표면 온도를 관련시키는 기준 열전달 분석을 채우는 제공 그래서 주요한 이유이다. </p><p class="jove_content"> 그것은 주로 온도에서 시간에 민감한 재료에 대한 설명서를 형성하는 과정으로, 실행 사이에 불일치는 실행예상합니다. 알루미늄 합금으로 인해 노화 메커니즘에 100 ° C 이상의 온도에 매우 민감 미세 있습니다. 블랭크는 고온에서 어디 따라서, 프로토콜 내에서 가장 중요한 단계는 1.2 3.3-3.7이다. 조임 재 안착 클램프 형성 작업 간 재현성을 유지하기 위해 가능한 한 신속하게 실시되어야한다. </p><p class="jove_content"> 예열 단계에서 이용되는 <em>반응계 공작물 가열은</em> 매우 비효율적이고, 복사 난방을 통해 개선 될 수있다. 달성 될 수있는 맨드릴 및 공구의 움직임의 측면에서 전체적인 처리 속도는 다소 이용 선반의 능력에 의해 제한된다. 높은 형성 속도는 더 강한 재질로 형성하는 시도했다 경우 특히 더 높은 부하 용량이 더 단단한 프레임이 필요합니다. 워크 클램프 및 해제는 유압 또는 공기압 작동의 첨가로 개선 될 수있다. 즐에서 열 전달로맨드릴에 NK 크게 맨드릴 상 워크에 의해 부과 된 압력의 함수이며,이 외에 또 기존 시스템 형성 동안 공작물의 온도를 확인하기위한 모델 - 기반 접근 방식을 개선 할 수있다. </p><p class="jove_content"> 설명 된 장치 및 절차는 이러한 조건이 자료에 대한 하중을 형성하는 표준 전환 작업에 대한 이러한 접근 및 제조 시험을 수행하는 의해 매우 비용 효율적인 프로세스 남아있는 것으로 나타났습니다. 다른 제조 경로와 성형에 대한 연구는 조작이 상당히 비싼 상업 형성 장비, 멀리 수행 할 수 있습니다. 장치 및 프로토콜이 설명으로, 처리 파라미터가 사전 대규모 높은 처리량 장비 구성을 조사 할 수 있고, 저자의 기술에 고유 한 방식이다. </p><p class="jove_content"> 개발 된 프로토콜은 주조 알루미늄 합금 중 하나가 특정 변형에 적용된 바와 같이,재 자동차 바퀴 이후 다양한 용도 조사 할 수있는 다른 알루미늄 주조 합금의 무리이다. 이러한 합금의 온도 관점으로부터 거의 마찬가지의 처리 창을 가지고, 개발 된 프로토콜은 쉽게 적응 될 수있다. </p>

<p class="jove_content"> 현재 항공 우주 및 운송 부문에서 실시되는 더 도전 금속 성형 작업 중 하나는 전단 형성과 흐름 <sup class="xref"><sup>(1),</sup></sup> <sup class="xref">(2)을</sup> 형성 유도체를 포함하는 금속 회전이다. 이 과정에서, 축 대칭 공작물 최종 원하는 형상을 나타내는 맨드릴에 배치되고, 하나 이상의 충돌하는 롤러와 접촉 스펀. 공작물은 다음 소성 결합 굽힘, 숱 및 축 신장을 포함하여 다양한 응답, 변형 롤러와 굴대 사이에서 압축된다. 한정 연성을 보유 또는 형성하기 어려운 재료이며, 이것은 때때로 유동 응력 확대 연성을 감소시키는 상승 된 온도에서 수행된다. </p><p class="jove_content"> 처리 관점에서 형상 및 제조 성분의 특성을 지시 할 수있는 다양한 파라미터들이있다. 많은 연구가 집중했다다양한 변수 <sup class="xref"><sup>3,</sup></sup> <sup class="xref"><sup>4,</sup></sup> <sup class="xref">5를</sup> 최적화하기위한 통계적 기법. 변수는 공구 및 맨드릴의 형상 등의 공구 형상을 포함한다; 맨드릴 둘 회전 속도 및 공구 이송 속도를 포함한 속도를 형성하는 단계; 뿐만 아니라 재료 특성 등. 승온이 필요한 경우,업자는 여전히 음향 제품을 유지하면서 최소 온도가 필요 평가할 필요가있다. </p><p class="jove_content"> 주조 알루미늄 합금은 자동차 바퀴에 사용되는 합금 A356으로, 자동차 및 항공 다양한 애플리케이션에 사용된다. 그러나,이 합금은 연성 제한 때문에, 실온 <sup class="xref"><sup class="xref"><sup>(6,</sup> 7)에</sup></sup> 형성하기에 적합하지 않고 고온에서 형성되어야한다. 이것은 주로 온도 제어의 복잡성을 처리하는 호스트를 도입한다. 이 물질의 특성은 significa을 변경하면ntly 온도를 <sup class="xref">8로,</sup> 열 조건이 적절한 처리 윈도우 내에서 유지 될 수 있고 모니터링 될 수있는 계측 시험을 수행하는 것이 특히 중요하다. 스트레인 비율의 넓은 범위에 걸쳐 실온에서 500 ℃의 범위로서 캐스트 A356의 열 기계적 동작에 대한 상세한 데이터는 다른 곳에서 평가 될 수있다. <sup class="xref">9</sup> </p><p class="jove_content"> 개발 및 휠 제조 작업을 형성하는 흐름의 최적화를 지원하기 위해, 사용자 정의 형성하는 장비는 브리티시 컬럼비아 대학 <strong>(그림 1)에서</strong> 재료 공학과에서 개발되었다. 이 장치는 기본적으로 22 kW의 총 출력, 82 킬로와트 <strong>(도 2)의</strong> 피크 출력 프로판 토치 가열 시스템과 수동, 벨트 구동 캡스턴 선반에서 내장하고있다. 단단한 롤러 어셈블리와 함께 포함 된 열전대와 맨드릴 <strong>(그림 3)하고있다</strong>직경 330mm까지의 가공품을 형성 할 수있는 설치. 맨드릴 <strong>(도 4)을</strong> 처리하는 동안 발생하는 공작물 직경이 큰 변화를 설명 할 수있는 수동 작동 클램핑 시스템을 갖는다. 배터리는 형성 동안 맨드릴의 온도를 모니터링하고 특성화 난방 빈은 선반의 퀼에 설치되어있는 소형 무선 컴퓨터를 포함하는 데이터 수집 (DAQ) 시스템을 운영했다. 다른 흐름을 형성하는 프로세스를 적응 선반을 사용하여 합성되었지만 <sup class="xref"><sup>(4)</sup></sup> <sup class="xref">(10)는,</sup> 본 장치는 <em>인 시츄</em> 열적 가열 및 데이터 <em>수집에</em> 구현 처음이다. </p><p class="jove_content"> 공업 적 스케일 형성 작업에 대한 처리 프로토콜을 나타내는 처리 조건을 제공하기 위해 개발되었다. 계속해서 설명하면,이 프로토콜은 공구와 공작물 준비, 형성 연습, 공동 구성시험 운영을 형성 끝 ncluding. </p><p class="jove_content" fo:keep-together.within-page="1"><img alt="그림 1" src="/files/ftp_upload/55061/55061fig1.jpg" /><br /> <strong>그림 1 :</strong> <strong>실험 장치 개요.</strong> 고온에서 형성 변성 캡스턴 선반에 추가 된 원리 요소. 장비 (위)와 컴퓨터 지원 설계 묘사 (하단)에 표시된 주요 작업 방향 및 구성 요소의 사진. <a href="https://ecsource-jove-com.bdigitaluss.remotexs.co/files/ftp_upload/55061/55061fig1large.jpg" target="_blank">이 그림의 더 큰 버전을 보려면 여기를 클릭하십시오.</a> </p><p class="jove_content" fo:keep-together.within-page="1"><img alt="그림 2" src="/files/ftp_upload/55061/55061fig2.jpg" /><br /> <strong>그림 2 : 난방 시스템 세부 사항입니다.</strong> 가스 제어 솔레노이드 (상부 및 하부 좌측)를 포함하는 중앙 다기관에서 작동 디스크리트 버너 (상부 및 하부 우측)과 프로판 가열 시스템.가스압 버너 각각 이산 유량은 다른 형상을 따르도록 블랭크 따라 배치와 함께 가능해진다. <a href="https://ecsource-jove-com.bdigitaluss.remotexs.co/files/ftp_upload/55061/55061fig2large.jpg" target="_blank">이 그림의 더 큰 버전을 보려면 여기를 클릭하십시오.</a> </p><p class="jove_content" fo:keep-together.within-page="1"><img alt="그림 3" src="/files/ftp_upload/55061/55061fig3.jpg" /><br /> <strong>그림 3 :</strong> <strong>롤러 어셈블리 세부 사항을 서있다.</strong> 선반은 임의의 롤러를 유지하도록 한 동안 원래 공구 홀더는 잼 너트 조립을 통해 맨드릴의 회전 축에 대해 각도. <a href="https://ecsource-jove-com.bdigitaluss.remotexs.co/files/ftp_upload/55061/55061fig3large.jpg" target="_blank">이 그림의 더 큰 버전을 보려면 여기를 클릭하십시오.</a> </p><p class="jove_content" fo:keep-together.within-page="1"><img alt="그림 4" src="/files/ftp_upload/55061/55061fig4.jpg" /><br /> <strong>그림 4 :</strong> <strong&gt; 계장 맨드릴 및 클램프 시스템 개요. 회전 공구는 테일 스톡 (상단과 하단 왼쪽)에 라이브 센터가 지원하는 턴에있는 선반 스핀들에 직접 볼트하도록 설계되었습니다. 클램프 조립 / 작업도 묘사된다 (상단과 하단 오른쪽). <a href="https://ecsource-jove-com.bdigitaluss.remotexs.co/files/ftp_upload/55061/55061fig4large.jpg" target="_blank">이 그림의 더 큰 버전을 보려면 여기를 클릭하십시오.</a> </p>

<table><tbody><tr><td>&lt;strong&gt;Reagent/Material&lt;/strong&gt;</td><td></td><td></td><td></td></tr><tr><td>High temperature grease</td><td>Dow Corning</td><td>Molycote M-77</td><td></td></tr><tr><td>High temperature lubricant</td><td>Superior Graphite</td><td>sureCOAT</td><td></td></tr><tr><td>High temperature die coat</td><td>Vesuvius/Foseco</td><td>DYCOTE 32</td><td></td></tr><tr><td>&lt;strong&gt;Name&lt;/strong&gt;</td><td>&lt;strong&gt;Company&lt;/strong&gt;</td><td>&lt;strong&gt;Catalog Number&lt;/strong&gt;</td><td>&lt;strong&gt;Comments&lt;/strong&gt;</td></tr><tr><td>&lt;strong&gt;Equipment&lt;/strong&gt;</td><td></td><td></td><td></td></tr><tr><td>Live center</td><td>Riten Industries</td><td>17124</td><td>Bell-head, spring loaded</td></tr><tr><td>Live center adapter</td><td>Riten Industries</td><td>431</td><td>Adapter for lathe</td></tr><tr><td>Impact wrench</td><td>Chicago Pneumatic</td><td>CP7749-2</td><td>1/2&quot; drive, 0-545 ft-lb</td></tr><tr><td>Torque wrench</td><td>Westward Tools</td><td>6PAG0</td><td>1/2&quot; drive, 0-250 ft-lb</td></tr><tr><td>Air-powered paint sprayer</td><td>Cambell Hausfeld</td><td>DH4200</td><td>For die coat</td></tr><tr><td>Air-powered paint sprayer</td><td>Cambell Hausfeld</td><td>DH5500</td><td>For graphite-based lubricant, high volume low pressure (HVLP) type</td></tr><tr><td>Data acquisition unit</td><td>Measurement Computing</td><td>USB-2416</td><td></td></tr><tr><td>Reed thermocouple</td><td>Omega Engineering</td><td>88108</td><td></td></tr><tr><td>Propane tank</td><td>Generic</td><td></td><td>20/40 lb, POL fitted</td></tr><tr><td>Solenoid valve</td><td>Aztec Heating</td><td>SV-S121</td><td></td></tr><tr><td>Gas regulator</td><td>Aztec Heating</td><td>67CH-743</td><td>0-30 psi</td></tr><tr><td>Burner tips</td><td>Exact</td><td>3119</td><td>Qty: 4</td></tr><tr><td>Roller bearings</td><td>SKF</td><td>32005 X/Q</td><td>Qty: 2</td></tr><tr><td>Remaining equipment designed and fabricated in-house</td><td></td><td></td><td></td></tr></tbody></table>

experimental procedure for warm spinning of cast aluminum components

<p class="jove_content"> 고성능 캐스팅 알루미늄 자동차 바퀴 갈수록 점진적으로 물성을 개선하기 위해 높은 온도에서 형성하는 유동 / 금속 방사를 통해 형성되어있다. 형상 획득 및 생성 된 물질의 특성 모두에 영향을 줄 수있는 처리 파라미터의 다양한 배열, 이러한 타입의 처리는위원회 악명 어렵다. 처리의 단순화, 경량 버전의 설계 및 전체 크기 자동차의 바퀴에 대해 구현되었다. 장치는 변형 처리 메커니즘이 유형의 반응 물질을 이해 지원하기위한 것이다. 실험 프로토콜을 형성하는 시험을 준비하고, 계속해서 수행하도록 개발되었으며 같은 주조 A356 휠 블랭크 설명한다. 열 프로파일은 기기 정보가 제공되는으로 함께 달성. 전체 규모는 빠른 속도에 훨씬 더 많은 변형을 부여하는 작업을 형성하는 비유는 설명한다. </p>

<p class="jove_content" fo:keep-together.within-page="1"> AS-cast 알루미늄 A356 공작물이 논문에 기재된 방법에 따라 형성 하였다. 공작물은 낮은 압력이 과정을 다이 캐스팅 사용하는 북미 휠 제조업체로 캐스트 휠에서 얻었다. 열전대 계측 한 공작물을 형성하지만, 프로세스의이 양태 중에 블랭크의 표면에 걸쳐 온도 분포를 캡처 예열 사이클 (프로토콜 부분 3 3.3-3.5 단계)을 시행하지 않았다. 이 응답은 <strong>그림 5에</strong> 표시됩니다. 또 3 샘플 변형의 높은 수준이 형성 패스를받은 것을 포함하여 다양한 수준으로 변형되었다. 처음 두 샘플 후자 샘플에서 수행 된 첫 번째 패스는 벽 두께가 작은 명백한 변화 공작물을 곧게 역임. 후자의 샘플 피크 두께 감소는 약 10 %이고 대부분은 제 PA 달성했다SS. 단면 블랭크로서 캐스트 및 미세 멀티 패스 샘플에서 얻은 <strong>결과는도 6에</strong> 도시되어있다. 여기서, 상기와 같은 캐스트 미세 크게 겨우 식별 할 수지상 기능과 프로세스에 의해 정제 할 수 표시됩니다. 수지상 정간 공정은으로 주조 상태에서보다 훨씬 더 균일 한 미세 조직을 생성, 부과 변형에 의해 파괴된다. 이것은 전체 연성뿐만 아니라 구성 요소의 피로 파괴 특성을 향상시킨다. 저자는 이전에 샘플 <sup class="xref"><sup>8,</sup></sup> <sup class="xref">13의</sup> 전체 집합에 미세에 공작물 형상, 벽 두께의 특정 단면 변화 관찰 결함 및 치수 변화의 자세한 내용을 설명했다. </p><p class="jove_content" fo:keep-together.within-page="1"><img alt="그림 5" src="/files/ftp_upload/55061/55061fig5.jpg" /><br /> <strong>그림 5 :</strong> <strong>굴대와 b의 전형적인 온도 프로파일</strong><html> 여윈. 블랭크 및 맨드릴의 대표적인 과도 열 응답은 가열 시스템 얻어. 수직 클램프가 예열 단계에서 강화 된 위치 선이 표시 점선과 검은 색 화살표가 형성 보여줍니다. 시스템이 냉각 동안 가열 시스템이 해제 된 경우 마지막 수직선을 보여줍니다. </p><p class="jove_content" fo:keep-together.within-page="1"><img alt="그림 6" src="/files/ftp_upload/55061/55061fig6.jpg" /><br /> <strong>그림 6 :로 캐스트 및 형성 결과.</strong> (가) 330mm (위)의 최소 내경을 갖는 빈 표면 형상을 그대로 전송할뿐만-수신은 도시 된 결과 (중간)을 제공하는 두 과정으로 변형시켰다. 대로의 캐스팅 수지상 미세이 (왼쪽 하단) 눈에 띄게 성형 수술 및 광학 현미경 <sup class="xref"><sup>(8),</sup></sup> <sup class="xref">(13)</sup> 관찰 등의 후속 T6 열처리 (오른쪽 아래)에 의해 수정된다.ig6large.jpg &quot;대상 =&quot;_ 빈 &quot;&gt;이 그림의 더 큰 버전을 보려면 여기를 클릭하십시오. </p>

Watch this Scientific Journal Video about Experimental Procedure for Warm Spinning of Cast Aluminum Components at JoVE.com

Experimental Procedure for Warm Spinning of Cast Aluminum Components

<p class="jove_content"> 맞춤형 산업 스케일 장치를 사용하는 주조 알루미늄 합금으로 형성 계측 따뜻한 회전에 대한 실험 프로토콜이 제공됩니다. 열 및 기계적 효과를 포함 실험 고려 사항은 자동차 바퀴의 본격적인 처리와 외모뿐만 아니라, 논의된다. </p>

캐스트 알루미늄 부품의 따뜻한 회전에 대한 실험 절차

High performance, cast aluminum automotive wheels are increasingly being incrementally formed via flow forming/metal spinning at elevated temperatures to ...

experimental-procedure-for-warm-spinning-of-cast-aluminum-components

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Rotation and Rigid Bodies

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9.4K 조회수.  University of Manchester.  맞춤형 산업 스케일 장치를 사용하는 주조 알루미늄 합금으로 형성 계측 따뜻한 회전에 대한 실험 프로토콜이 제공됩니다. 열 및 기계적 효과를 포함 실험 고려 사항은 자동차 바퀴의 본격적인 처리와 외모뿐만 아니라, 논의된다. 

비디오: Experimental Procedure for Warm Spinning of Cast Aluminum Components

Enthalpy of Reaction

Enthalpy of Reaction and Measurement of Heat by Calorimeter - procedure

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Source: Smaa Koraym at Johns Hopkins University, MD, USA

	Collecting Data for Calculating the Heat Capacity of a CalorimeterExpand
	This experiment will ...

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Metal Flame Emission

<p>Source: Smaa Koraym at Johns Hopkins University, MD, USA</p>
<ol class="note-items">
	<li data-note-item="1" data-parent-collapse="">Metal Flame Emission Testing<button class="expand">Expand</button>
	<p>In this lab, you will excite the electrons of six metal chloride salts with heat from a flame and measure the wavelength of light emitted by the relaxing electrons. The emitted light is in the visible spectrum, so you will see different colored flames for the different metals.</p>
	<p>At the end of the lab, you will measure the emission spectrum of a sparkler and use the data you collected from the metal salts to identify the metals in the sparkler. To help with this process, make a table in your lab notebook to record the wavelengths emitted from ambient light, the salts, and the sparkler.</p>
	<h4><strong>Table 1: Observed Wavelengths</strong></h4>
	<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
		<tbody>
			<tr>
				<td style="text-align: center;"><strong>Run #</strong></td>
				<td style="text-align: center;"><strong>Source</strong></td>
				<td style="text-align: center;"><strong>Recorded wavelength(s)</strong></td>
			</tr>
			<tr>
				<td style="text-align: center;">1</td>
				<td style="text-align: center;">Room lights</td>
				<td></td>
			</tr>
			<tr>
				<td style="text-align: center;">2</td>
				<td style="text-align: center;">NaCl</td>
				<td></td>
			</tr>
			<tr>
				<td style="text-align: center;">3</td>
				<td style="text-align: center;">LiCl</td>
				<td></td>
			</tr>
			<tr>
				<td style="text-align: center;">4</td>
				<td style="text-align: center;">KCl</td>
				<td></td>
			</tr>
			<tr>
				<td style="text-align: center;">5</td>
				<td style="text-align: center;">SrCl<sub>2</sub></td>
				<td></td>
			</tr>
			<tr>
				<td style="text-align: center;">6</td>
				<td style="text-align: center;">BaCl<sub>2</sub></td>
				<td></td>
			</tr>
			<tr>
				<td style="text-align: center;">7</td>
				<td style="text-align: center;">CuCl<sub>2</sub></td>
				<td></td>
			</tr>
			<tr>
				<td style="text-align: center;">8</td>
				<td style="text-align: center;">Sparkler</td>
				<td></td>
			</tr>
		</tbody>
	</table>
	<p><a href="https://www-jove-com.bdigitaluss.remotexs.co/CDNSource/lm/labs/48/Table_1._Observed_Wavelengths.xlsx" target="_blank">Click Here to download Table 1</a></p>
	<p>During this lab, you will hold a salt-coated applicator at the edge of a Bunsen burner flame to excite the metal salts. If the applicator catches fire, immediately quench it in a beaker of water. For excitation, you will hold a detector near the flame and the sparkler to measure the wavelengths of the emitted light. Keep a safe distance to protect yourself and the detector. As some tasks are performed simultaneously, we suggest that you work in groups of four with each student completing tasks as needed.</p>
	<ul class="lab-items">
		<li data-sub-note-item="1-4">
		<div class="lab-step">Put on a lab coat, safety glasses, and nitrile gloves.</div>
		</li>
		<li data-sub-note-item="1-5">
		<div class="lab-step">Set up the Bunsen burner in the fume hood.</div>
		</li>
		<li data-sub-note-item="1-6">
		<div class="lab-step">Fill a 400-mL beaker with tap water and bring it to the hood. Place the salts, applicators, and tap water within easy reach on one side of the Bunsen burner.</div>
		</li>
		<li data-sub-note-item="1-7">
		<div class="lab-step">Turn on the hand-held spectrophotometer and familiarize yourself with its components.</div>
		</li>
		<li data-sub-note-item="1-8">
		<div class="lab-step">Create a new experiment and configure the spectrometer to measure emission intensity. Set the sample time to 200 ms and the number of readings at a given wavelength to 1. Record the settings and the experiment name in your lab notebooks.</div>
		</li>
		<li data-sub-note-item="1-9">
		<div class="lab-step">Measure the spectrum of the room lights. Have one or two students hold the optical detector as close to the lights as possible without disconnecting the cables. Once ready, have a different student start the spectrometer. The spectrum should be clear, with minimal noise and no off-scale peaks. <strong>Note: </strong>If you have trouble, hold the probe in a nearly closed drawer or box to shield it from sunlight while pointing it at the room lights.</div>
		</li>
		<li data-sub-note-item="1-10">
		<div class="lab-step">Immediately capture the spectrum when it looks good. Confirm that you have a high-quality spectrum before saving it. Record the wavelengths of the peaks in your data table.</div>
		</li>
		<li data-sub-note-item="1-11">
		<div class="lab-step">Measure the emission spectra of the metal salts. Ignite the Bunsen burner and adjust the collar until the flame distinctly separates into an inner and outer flame.</div>
		</li>
		<li data-sub-note-item="1-12">
		<div class="lab-step">Bring the spectrometer to the hood and arrange the cables so that the detector can be held about one inch from the flame.</div>
		</li>
		<li data-sub-note-item="1-13">
		<div class="lab-step">Have one student prepare the spectrometer for the run. This student should have a clear view of the burner so they can begin acquiring data as soon as the salt enters the flame. Then, have another student hold the detector no closer than one inch from the flame. <strong>Note: </strong>Any closer risks damaging the detector. But you won&#39;t get a clear spectrum if the detector is too far away.</div>
		</li>
		<li data-sub-note-item="1-14">
		<div class="lab-step">Have a different student take one of the applicators from the beaker of water and dip it into the tube of NaCl to coat the wet cotton with the salt. Then, carefully insert the salt-coated applicator about 1 mm into the outer flame, which will change color.</div>
		</li>
		<li data-sub-note-item="1-15">
		<div class="lab-step">Start the spectrometer when the applicator enters the flame.<strong> Note: </strong>If the peak intensities are off-scale, adjust the detector position until all peaks are within detection limits. If the flame color change is hard to see, pick up more salt on the same applicator and try again until you see an intense color. If the spectrum is noisy or weak, try pointing the detector at a different part of the flame.</div>
		</li>
		<li data-sub-note-item="1-16">
		<div class="lab-step">When you see a good spectrum, capture and save it. Everyone should review the spectrum to ensure that it is of good quality. Write down the emission wavelengths in your table.</div>
		</li>
		<li data-sub-note-item="1-17">
		<div class="lab-step">Submerge the NaCl applicator in your wastewater beaker. Always use a different applicator for each salt.</div>
		</li>
		<li data-sub-note-item="1-18">
		<div class="lab-step">Follow the same procedure to test the remaining five salts, being careful to avoid cross-contamination between the salts. Once you have tested the last salt and recorded the wavelengths, set up data collection for the sparkler.</div>
		</li>
		<li data-sub-note-item="1-19">
		<div class="lab-step">At the instructor&#39;s hood, light the sparkler with the Bunsen burner and place it handle down in the Erlenmeyer flask. Remember, the sparks may be very hot. Turn off the gas to extinguish the Bunsen burner.</div>
		</li>
		<li data-sub-note-item="1-20">
		<div class="lab-step">As one student holds the detector close to the sparkler, have another student start data collection. Position the detector to get as many peaks in scale as possible without losing the less intense peaks.</div>
		</li>
		<li data-sub-note-item="1-21">
		<div class="lab-step">Capture and save the spectrum once it looks good. Remember to write down the wavelengths in your table. <strong>Note: </strong>If the sparkler is long-lived, collect a second spectrum and either choose the best one or keep them both for the analysis.</div>
		</li>
		<li data-sub-note-item="1-22">
		<div class="lab-step">Let the sparkler burn out in the hood while you send the collected data to everyone in the group and shut down the data acquisition system.</div>
		</li>
		<li data-sub-note-item="1-23">
		<div class="lab-step">Bring the copper, barium, and strontium tubes to the waste hood and thoroughly rinse the tubes with deionized water into the designated waste container.</div>
		</li>
		<li data-sub-note-item="1-24">
		<div class="lab-step">Flush the sodium, potassium, and lithium salts down the drain and rinse the remaining test tubes. Put away the test tubes and the other equipment.</div>
		</li>
		<li data-sub-note-item="1-25">
		<div class="lab-step">Once the ashes and sparkler handle have cooled, dump them in the trash.</div>
		</li>
	</ul>
	</li>
	<li data-note-item="2" data-parent-collapse="">Results<button class="expand">Expand</button>
	<ul class="lab-items">
		<li data-sub-note-item="2-1">
		<div class="lab-step">First, plot the data for each run with intensity on the y-axis and wavelength on the x-axis.</div>
		</li>
		<li data-sub-note-item="2-2">
		<div class="lab-step">Compare the sparkler spectrum to the background spectrum from the room lights. Identify which small peaks may be from the room lights.</div>
		</li>
		<li data-sub-note-item="2-3">
		<div class="lab-step">Compare the metal spectra to the sparkler spectrum. Sodium appears to be the source of the peak at about 589 nm. There are no peaks matching the lithium spectrum, but potassium matches the large peak at 770 nm.</div>
		</li>
		<li data-sub-note-item="2-4">
		<div class="lab-step">The sparkler spectrum doesn&#39;t seem to have strontium peaks. However, barium is a good match for several peaks in the sparkler spectrum. Lastly, no copper seems to be present in the sparkler. Thus, we conclude that the sparkler was burning sodium, potassium, and barium when the spectrum was acquired.</div>
		</li>
	</ul>
	</li>
</ol>

금속 화염 방출

Source: Smaa Koraym at Johns Hopkins University, MD, USA

	Metal Flame Emission TestingExpand
	In this lab, you will excite the electrons of six metal ...

Balmer Series

<p>Source: Smaa Koraym at Johns Hopkins University, MD, USA</p>
<ol class="note-items">
	<li data-note-item="1" data-parent-collapse="">Spectral Emission Lines of Hydrogen, Helium, and Neon<button class="expand">Expand</button>
	<p>In this experiment, you will use a spectrophotometer to measure the distinct wavelengths of light emitted in the UV and visible range by electron relaxation in hydrogen, helium, and neon. Before starting the lab, make a table in your lab notebook for the elements that you will analyze, the color of the light that you observe from the lamps, and the recorded wavelengths.</p>
	<h4><strong>Table 1: Emission Wavelengths</strong></h4>
	<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
		<tbody>
			<tr>
				<td style="text-align: center;"><strong>Elements</strong></td>
				<td style="text-align: center;"><strong>Color</strong></td>
				<td style="text-align: center;"><strong>Distinct wavelengths, &#955; (nm)</strong></td>
			</tr>
			<tr>
				<td style="text-align: center;">H</td>
				<td style="text-align: center;"></td>
				<td style="text-align: center;"></td>
			</tr>
			<tr>
				<td style="text-align: center;">He</td>
				<td style="text-align: center;"></td>
				<td style="text-align: center;"></td>
			</tr>
			<tr>
				<td style="text-align: center;">Ne</td>
				<td style="text-align: center;"></td>
				<td style="text-align: center;"></td>
			</tr>
		</tbody>
	</table>
	<p><a href="https://www-jove-com.bdigitaluss.remotexs.co/CDNSource/lm/labs/54/Table_1._Emission_wavelengths.xlsx" target="_blank">Click Here to download Table 1</a></p>
	<ul class="lab-items">
		<li data-sub-note-item="1-2">
		<div class="lab-step">First, put on a lab coat, safety glasses, and nitrile gloves. We suggest students work in pairs for this experiment.</div>
		</li>
		<li data-sub-note-item="1-3">
		<div class="lab-step">Turn on a hand-held spectrophotometer and create a new file for the hydrogen emission spectrum. Configure the spectrophotometer to measure emission intensity with a sampling time of 200 ms, with no sample averaging.</div>
		</li>
		<li data-sub-note-item="1-4">
		<div class="lab-step">When the instructor calls you, bring the spectrophotometer to the hydrogen lamp. The student holding the sensor should move close to the lamp, and the other should be ready to start the spectrophotometer acquisition.</div>
		</li>
		<li data-sub-note-item="1-5">
		<div class="lab-step">When the instructor turns on the lamp, hold the sensor at the center of the lamp and start displaying the spectrum. <strong>Note: </strong>Capture the spectrum as soon as it is clear and has minimal noise, as the lamp cannot be left on for more than 30 s at a time.</div>
		</li>
		<li data-sub-note-item="1-6">
		<div class="lab-step">Save the hydrogen spectrum. Set up another experiment using the same parameters and acquire the spectrum for helium. Acquire a spectrum of neon in the same way.</div>
		</li>
		<li data-sub-note-item="1-7">
		<div class="lab-step">Export your saved data, turn off the spectrophotometer, and put it away.</div>
		</li>
	</ul>
	</li>
	<li data-note-item="2" data-parent-collapse="">Results<button class="expand">Expand</button>
	<ul class="lab-items">
		<li data-sub-note-item="2-1">
		<div class="lab-step">Set up the Rydberg formula to calculate the wavelengths of the Balmer series. <strong>Note:</strong> n<sub>initial</sub> is the number of the energy level where the excited electron starts, and n<sub>final</sub> is the energy level to which the electron relaxes. Set n<sub>final</sub> to 2.
		<h4><strong>Table 2: Frequency and Energy for Each Wavelength</strong></h4>
		<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
			<tbody>
				<tr>
					<td><strong>Rydberg constant (m<sup>-1</sup>) </strong></td>
					<td style="text-align: center;">1.098 &#215; 10<sup>7</sup></td>
				</tr>
				<tr>
					<td><strong>c (m/s)</strong></td>
					<td style="text-align: center;">2.998 &#215; 10<sup>8</sup></td>
				</tr>
				<tr>
					<td><strong>h (J&#183;s)</strong></td>
					<td style="text-align: center;">6.626 &#215; 10<sup>-34</sup></td>
				</tr>
				<tr>
					<td style="text-align: center;"><strong>ni &#8594; nf</strong></td>
					<td style="text-align: center;"><strong>&#955;<sub>calculated </sub>(nm) </strong></td>
					<td style="text-align: center;"><strong>&#955;<sub>measured</sub> (nm) </strong></td>
					<td style="text-align: center;"><strong>v (THz) </strong></td>
					<td style="text-align: center;"><strong>E (eV) </strong></td>
				</tr>
				<tr>
					<td style="text-align: center;">7 &#8594; 2</td>
					<td></td>
					<td></td>
					<td></td>
					<td></td>
				</tr>
				<tr>
					<td style="text-align: center;">6 &#8594; 2</td>
					<td></td>
					<td></td>
					<td></td>
					<td></td>
				</tr>
				<tr>
					<td style="text-align: center;">5 &#8594; 2</td>
					<td></td>
					<td></td>
					<td></td>
					<td></td>
				</tr>
				<tr>
					<td style="text-align: center;">4 &#8594; 2</td>
					<td></td>
					<td></td>
					<td></td>
					<td></td>
				</tr>
				<tr>
					<td style="text-align: center;">3 &#8594; 2</td>
					<td></td>
					<td></td>
					<td></td>
					<td></td>
				</tr>
			</tbody>
		</table>
		<a href="https://www-jove-com.bdigitaluss.remotexs.co/CDNSource/lm/labs/54/Table_2._Frequency_and_energy_for_each_wavelength.xlsx" target="_blank">Click Here to download Table 2</a></div>
		</li>
		<li data-sub-note-item="2-2">
		<div class="lab-step">Find the wavelength of light emitted by an electron relaxing from level 3 to level 2. Fill in the Rydberg constant for R<sub>H</sub> and solve for 1/&#955;. <strong>Note:</strong> The reciprocal of this value is the wavelength, which can be converted to nm.</div>
		</li>
		<li data-sub-note-item="2-3">
		<div class="lab-step">Calculate the transitions from energy levels 4, 5, 6, and 7 in the same way. <strong>Note: </strong>You should see a good match between your data and your calculations.</div>
		</li>
		<li data-sub-note-item="2-4">
		<div class="lab-step">For each wavelength, calculate the frequency in THz and the energy in eV using the following equations, where c is the speed of light and h is Planck&#39;s constant.
		<ul>
			<li><img src="https://www-jove-com.bdigitaluss.remotexs.co/CDNSource/lm/labs/54/54_Procedure_1.jpg" /></li>
			<li><img src="https://www-jove-com.bdigitaluss.remotexs.co/CDNSource/lm/labs/54/54_Procedure_2.jpg" /></li>
		</ul>
		</div>
		</li>
	</ul>
	<p>Look at the calculated energies. You should see a trend of the energy gap increasing by less with each added energy level. This is reflected in the spacing of the peaks in the hydrogen emission spectrum. Helium and neon share this energy level spacing trend.</p>
	<p>From the helium spectrum, adding even one more electron makes the spectral series harder to calculate and identify. This is even more apparent in neon, which has eight more electrons than helium.</p>
	</li>
</ol>

The Hydrogen Atom: Bohr Model and Balmer Series - Procedure

발머 시리즈

Source: Smaa Koraym at Johns Hopkins University, MD, USA

	Spectral Emission Lines of Hydrogen, Helium, and NeonExpand
	In this experiment, you will use a ...

Temperature Dependence

<p>Source: Smaa Koraym at Johns Hopkins University, MD, USA</p>
<ol class="note-items">
	<li data-note-item="1" data-parent-collapse="">Temperature Dependent Decomposition of Hydrogen Peroxide<button class="expand">Expand</button>
	<p><em>We suggest that students work in pairs for this experiment. Equipment controls may vary.</em></p>
	<p>In this lab, you&#39;ll perform a decomposition reaction where a single compound breaks down into two or more simpler products. You will observe the decomposition of hydrogen peroxide into water and oxygen. This decomposition happens very slowly, so you will use iron (III) nitrate as a catalyst to lower the activation energy.</p>
	<p>During this process, iron undergoes a redox reaction and then returns to its starting oxidation state. You will be able to see this as a color change in your solution during the reaction. You&#39;ll perform the same reaction at four different temperatures and track the rate of the reaction by recording the pressure inside the flask. This way you can measure how quickly oxygen was produced in each experiment. You&#39;ll use this to calculate the reaction&#39;s activation energy.</p>
	<p><strong>Table 1. Estimate the apparent activation energy for the decompostion of hydrogen peroxide</strong></p>
	<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
		<tbody>
			<tr>
				<td><strong>Trial&#160;</strong></td>
				<td><strong>Temperature (&#8451;)</strong></td>
				<td><strong>&#916;P (kPa/s)</strong></td>
				<td><strong>1/T&#160;</strong></td>
				<td><strong>ln (&#916;P)</strong></td>
			</tr>
			<tr>
				<td>1</td>
				<td></td>
				<td></td>
				<td></td>
				<td></td>
			</tr>
			<tr>
				<td>2</td>
				<td></td>
				<td></td>
				<td></td>
				<td></td>
			</tr>
			<tr>
				<td>3</td>
				<td></td>
				<td></td>
				<td></td>
				<td></td>
			</tr>
			<tr>
				<td>4</td>
				<td></td>
				<td></td>
				<td></td>
				<td></td>
			</tr>
		</tbody>
	</table>
	<p><a href="/CDNSource/labs/51/Table_1._Estimate_the_apparent_activation_energy_of.xlsx" target="_blank">Click Here to download Table 1</a> &#160;</p>
	<ul class="lab-items">
		<li data-sub-note-item="1-1">
		<div class="lab-step">Before starting this experiment, put on a lab coat, safety glasses, and nitrile gloves.</div>
		</li>
		<li data-sub-note-item="1-2">
		<div class="lab-step">Ensure that your hot plate is off and then place a 600-mL beaker on the hot plate.</div>
		</li>
		<li data-sub-note-item="1-3">
		<div class="lab-step">Connect vacuum tubing to the barbed sidearm of a 125-mL B&#252;chner filter flask, and carefully clamp the filter flask in the 600-mL beaker so that the sidearm is just above the top of the beaker.</div>
		</li>
		<li data-sub-note-item="1-4">
		<div class="lab-step">Fill a 400-mL beaker with deionized water., and pour the water into the 600-mL beaker until the water level is about 2&#8211;3 cm below the side arm.<br />
		<strong>NOTE</strong>: Make sure that the water is not able to get into the flask or vacuum line.</div>
		</li>
		<li data-sub-note-item="1-5">
		<div class="lab-step">Immerse the thermometer in the water, clamping it in place so that the end is in contact with the outer wall of the flask. Ensure that you can read the current temperature, as well as the 40, 60, and 80 &#176;C marks.</div>
		</li>
		<li data-sub-note-item="1-6">
		<div class="lab-step">Make sure that each hole of the 2-hole adapter is fitted with a tapered locking adapter. Check that all the adapters are firmly seated, since any air that escapes around them will affect your data.</div>
		</li>
		<li data-sub-note-item="1-7">
		<div class="lab-step">Lock a 2-way stopcock into one of the stopper adapters. Then, lock one end of the flexible tubing into the second adapter with the other end into the connector of the gas pressure sensor.</div>
		</li>
		<li data-sub-note-item="1-8">
		<div class="lab-step">Turn on the data acquisition device for the gas pressure sensor and ensure that the pressure is displayed in kPa.</div>
		</li>
		<li data-sub-note-item="1-9">
		<div class="lab-step">Set the acquisition rate to two samples per second and the duration to 300 s. Then, display the pressure in real-time.</div>
		</li>
		<li data-sub-note-item="1-10">
		<div class="lab-step">Label a 400-mL beaker as &#8216;waste&#8217;, a 50-mL beaker as &#8216;0.5 M Fe(NO<sub>3</sub>)<sub>3</sub>&#8217;, and a 100-mL beaker as &#8216;3% w/w hydrogen peroxide&#8217;.</div>
		</li>
		<li data-sub-note-item="1-12">
		<div class="lab-step">Place a few paper towels on the work surface as a clean area for glassware that you will reuse. Keep a supply of paper towels on hand for later.</div>
		</li>
		<li data-sub-note-item="1-13">
		<div class="lab-step">Then, bring the 50-mL and 100-mL beakers to the stock solution area. Pour about 30 mL of 0.5 M Fe(NO<sub>3</sub>)<sub>3</sub> in the 50-mL beaker and 100 mL of 3% w/w hydrogen peroxide in the 100-mL beaker.</div>
		</li>
		<li data-sub-note-item="1-14">
		<div class="lab-step">Back at your workspace, setup a 20-mL volumetric pipette and fill it to the mark with 3% w/w hydrogen peroxide. Dispense the hydrogen peroxide into the filter flask and set the volumetric pipette aside.</div>
		</li>
		<li data-sub-note-item="1-15">
		<div class="lab-step">Adjust the thermometer as needed so that it contacts the flask below the hydrogen peroxide solution level.</div>
		</li>
		<li data-sub-note-item="1-16">
		<div class="lab-step">Fit the rubber stopper into the mouth of the filter flask, being careful not to loosen the connections to the sensor and the 2-way stopcock.</div>
		</li>
		<li data-sub-note-item="1-17">
		<div class="lab-step">Check that the 2-way stop is closed. Open the vacuum line and monitor the pressure as it decreases. This will seal the stopper in the flask. Once the pressure reaches 10 kPa, close the vacuum.</div>
		</li>
		<li data-sub-note-item="1-18">
		<div class="lab-step">Monitor the pressure for at least 1 min to confirm there are no slow leaks.<br />
		<strong>NOTE</strong>: If the pressure immediately starts rapidly increasing, there is a leak in your setup, so tighten the connections and try again until the pressure holds at 10 kPa when the vacuum line is closed.</div>
		</li>
		<li data-sub-note-item="1-19">
		<div class="lab-step">Draw 5 mL of 0.5 M Fe(NO<sub>3</sub>)<sub>3</sub> into a 20-mL syringe. Expel all air from the syringe so that it only contains the solution.</div>
		</li>
		<li data-sub-note-item="1-20">
		<div class="lab-step">Lock the syringe into the top of the 2-way stopcock. You are now ready to start the room temperature trial, so record the water temperature in your lab notebook.</div>
		</li>
		<li data-sub-note-item="1-21">
		<div class="lab-step">Start acquiring gas pressure data. Allow the device to record data for about 15 s, then open the stopcock and quickly close it once all of the Fe(NO<sub>3</sub>)<sub>3</sub> has entered the flask. The observed increase in pressure is from the evolution of oxygen gas produced by the decomposition of hydrogen peroxide.</div>
		</li>
		<li data-sub-note-item="1-22">
		<div class="lab-step">Once the data collection finishes, save your data. Then, disconnect the syringe and open the stopcock to vent the flask.</div>
		</li>
		<li data-sub-note-item="1-23">
		<div class="lab-step">Take out the rubber stopper, carefully remove the thermometer from the clamp and the flask from the beaker, and disconnect the vacuum tubing from the filter flask.</div>
		</li>
		<li data-sub-note-item="1-24">
		<div class="lab-step">Empty the flask into the waste beaker. Try not to get liquid in the side arm. Dry the outside of the flask with paper towels.</div>
		</li>
		<li data-sub-note-item="1-25">
		<div class="lab-step">Rinse the interior of the flask with deionized water and pour the rinse into the waste beaker. If any liquid gets into the side arm, remove it with paper towels.</div>
		</li>
		<li data-sub-note-item="1-26">
		<div class="lab-step">Reconnect the flask to the vacuum line and clamp it in the 600-mL beaker in contact with the thermometer.</div>
		</li>
		<li data-sub-note-item="1-27">
		<div class="lab-step">Turn on the hotplate and heat the water around the flask until the thermometer reads 80 &#176;C. Then, turn off the heat.</div>
		</li>
		<li data-sub-note-item="1-28">
		<div class="lab-step">Then, add 20 mL of 3% w/w hydrogen peroxide to the flask.</div>
		</li>
		<li data-sub-note-item="1-29">
		<div class="lab-step">Dry the stopper with paper towels. Do this after each trial to ensure that the stopper has a snug fit in the neck of the beaker and fit the stopper in the flask.</div>
		</li>
		<li data-sub-note-item="1-30">
		<div class="lab-step">Check that the stopcock is closed and evacuate the flask to about 10 kPa. Then, close the vacuum and confirm that there are no leaks.</div>
		</li>
		<li data-sub-note-item="1-31">
		<div class="lab-step">Draw 5 mL Fe(NO<sub>3</sub>)<sub>3</sub> solution into the syringe, expel the air from the syringe, and connect it to the stopcock.</div>
		</li>
		<li data-sub-note-item="1-32">
		<div class="lab-step">Record the temperature shown on the thermometer in your lab notebook, then, start collecting data.</div>
		</li>
		<li data-sub-note-item="1-33">
		<div class="lab-step">Wait about 15 s and introduce the Fe(NO<sub>3</sub>)<sub>3</sub> solution in the same way as before.<br />
		<strong>NOTE:</strong> As the pressure approaches 150 kPa, the stopper may pop off!</div>
		</li>
		<li data-sub-note-item="1-34">
		<div class="lab-step">After data collection finishes, save the data, vent and clean the filter flask, and set up for the third trial.</div>
		</li>
		<li data-sub-note-item="1-35">
		<div class="lab-step">Fill the 400-mL beaker with ice and add some to cool the water to about 60 &#176;C.</div>
		</li>
		<li data-sub-note-item="1-36">
		<div class="lab-step">Perform the third trial in the same way as before. Remember to dry the stopper and the inside of the flask and to record the temperature prior to data collection.</div>
		</li>
		<li data-sub-note-item="1-37">
		<div class="lab-step">After the data is collected for that trial, cool the water to about 40 &#176;C and perform the fourth trial.</div>
		</li>
		<li data-sub-note-item="1-38">
		<div class="lab-step">Once you have finished all four trials, empty the filter flask and rinse it into the waste beaker one last time.</div>
		</li>
		<li data-sub-note-item="1-39">
		<div class="lab-step">Dispose of any excess 0.5 M Fe(NO<sub>3</sub>)<sub>3</sub> and the contents of the waste beaker in a container labeled for aqueous iron waste.</div>
		</li>
		<li data-sub-note-item="1-40">
		<div class="lab-step">Then, disassemble the apparatus and pour the leftover ice, water, and hydrogen peroxide in the sink. Wash your glassware following your lab&#39;s standard protocol.</div>
		</li>
	</ul>
	</li>
	<li data-note-item="1" data-parent-collapse="">Results<button class="expand">Expand</button>
	<p>The decomposition of hydrogen peroxide with iron is a complex, multi-step process that we can&#39;t easily describe in a single equation. However, we can estimate the apparent activation energy from the rate of oxygen production and compare it to the apparent activation energy of the un-catalyzed process.</p>
	<ul class="lab-items">
		<li data-sub-note-item="2-1">
		<div class="lab-step">Find the rate of pressure change, which is directly proportional to the rate of oxygen production. For each experiment, make a plot of pressure with respect to time and find the point where the reaction started.</div>
		</li>
		<li data-sub-note-item="2-2">
		<div class="lab-step">Identify the maximum pressure attained and determine the slope between the two points.</div>
		</li>
		<li data-sub-note-item="2-3">
		<div class="lab-step">Once you&#39;ve determined the slopes and the corresponding temperatures in Kelvin for all of the temperatures, use the Arrhenius equation to estimate the apparent activation energy of this reaction.</div>
		</li>
		<li data-sub-note-item="2-4">
		<div class="lab-step">Take the reciprocal of the temperatures in Kelvin and the natural log of the rate of change in pressure. Remember that the rate constant k is essentially equal to the change in pressure.</div>
		</li>
		<li data-sub-note-item="2-5">
		<div class="lab-step">Make an Arrhenius plot and find the slope of the line.</div>
		</li>
		<li data-sub-note-item="2-6">
		<div class="lab-step">The slope is equal to the negative activation energy over the universal gas constant, so multiply the slope by the negative universal gas constant to get the apparent activation energy of the iron catalyzed decomposition reaction. You&#39;ll see a value in the range of 35&#8211;60 kJ/mol because the iron catalyst made the decomposition take less energy. The apparent activation energy of the uncatalyzed decomposition of hydrogen peroxide is around 78 &#8211; 88 kJ/mol.</div>
		</li>
	</ul>
	</li>
</ol>

Temperature Dependence and Arrhenius Equation - Procedure

온도 의존성

Source: Smaa Koraym at Johns Hopkins University, MD, USA

	Temperature Dependent Decomposition of Hydrogen PeroxideExpand
	We suggest that students work ...

Electrolytic Cells

<p>Source: Smaa Koraym at Johns Hopkins University, MD, USA</p>
<ol class="note-items">
	<li data-note-item="1" data-parent-collapse="">Electrolytic Cells<button class="expand">Expand</button>
	<p>In this experiment, you will be assembling an electrolytic cell to perform electroplating. An electrolytic cell contains an anode and cathode connected by a power source, which drives the nonspontaneous redox reaction in the cell. When the anode material is oxidized, the ions travel to the cathode, where they are reduced and plated.</p>
	<p>In the case of this experiment, the electrolytic cell contains a copper anode and a brass key for the cathode. Oxidation of the anode creates copper(2+) ions, which are then reduced on the brass key, forming a thin plating of solid copper.</p>
	<ul class="lab-items">
		<li data-sub-note-item="1-3">
		<div class="lab-step">Put on gloves, safety goggles, and a lab apron, which must be worn at all times.</div>
		</li>
		<li data-sub-note-item="1-4">
		<div class="lab-step">Obtain one 10-ohm resistor, one copper sheet electrode, one copper wire, and one piece of emery paper.</div>
		</li>
		<li data-sub-note-item="1-5">
		<div class="lab-step">Use the emery paper to polish the brass key and the copper sheet. Rinse the key and the copper electrode with water. The brass key will be the cathode, and the copper sheet will be the anode.</div>
		</li>
		<li data-sub-note-item="1-6">
		<div class="lab-step">Take one 50-mL beaker and a watch glass to the instructor&#39;s hood and obtain approximately 20 mL of acetone. Place the watch glass on top of the beaker to prevent evaporation and bring it back to your bench.</div>
		</li>
		<li data-sub-note-item="1-7">
		<div class="lab-step">Label the other 50-mL beaker as &#39;organic waste&#39;.</div>
		</li>
		<li data-sub-note-item="1-8">
		<div class="lab-step">Use a disposable pipette to rinse the copper electrode and key with acetone. Collect excess in the waste beaker. Place the key and copper electrode on a paper towel to dry.</div>
		</li>
		<li data-sub-note-item="1-9">
		<div class="lab-step">Measure the initial masses of the key and copper electrode and record their values in your lab notebook.
		<h4><strong>Table 1: Moles of Cu Transferred</strong></h4>
		<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
			<tbody>
				<tr>
					<td></td>
					<td style="text-align: center;"><strong>Mass of key (g) </strong></td>
					<td style="text-align: center;"><strong>Change in mass (g) </strong></td>
					<td style="text-align: center;"><strong>Moles Cu plated </strong></td>
					<td style="text-align: center;"><strong>Mass of Cu electrode (g) </strong></td>
					<td style="text-align: center;"><strong>Change in mass (g) </strong></td>
					<td style="text-align: center;"><strong>Moles Cu lost </strong></td>
				</tr>
				<tr>
					<td style="text-align: center;">0 min</td>
					<td></td>
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				</tr>
				<tr>
					<td style="text-align: center;">5 min</td>
					<td></td>
					<td></td>
					<td></td>
					<td></td>
					<td></td>
					<td></td>
				</tr>
				<tr>
					<td style="text-align: center;">1<sup>st</sup> 30 min</td>
					<td></td>
					<td></td>
					<td></td>
					<td></td>
					<td></td>
					<td></td>
				</tr>
				<tr>
					<td style="text-align: center;">2<sup>nd</sup> 30 min</td>
					<td></td>
					<td></td>
					<td></td>
					<td></td>
					<td></td>
					<td></td>
				</tr>
			</tbody>
		</table>
		<a href="https://www-jove-com.bdigitaluss.remotexs.co/CDNSource/lm/labs/53/Table_1._Moles_of_Cu_Transferred.xlsx" target="_blank">Click Here to download Table 1</a></div>
		</li>
		<li data-sub-note-item="1-10">
		<div class="lab-step">Set up the electrolytic cell. Use one electrical wire with alligator clips to connect the negative terminal on the battery to the current probe. Wrap the 10-ohm resistor around the other end of the current probe.</div>
		</li>
		<li data-sub-note-item="1-11">
		<div class="lab-step">Use another wire to connect the positive terminal on the battery to the copper electrode.</div>
		</li>
		<li data-sub-note-item="1-12">
		<div class="lab-step">Wrap the copper wire around the brass key and use an electrical wire to connect the resistor on the current probe to the copper wire on the brass key.</div>
		</li>
		<li data-sub-note-item="1-13">
		<div class="lab-step">Obtain about 200 mL of concentrated copper sulfate in a 250-mL beaker. The amount does not need to be exact. Bring the beaker back to your bench and set it on the stir plate. Carefully, place a magnetic stir bar in the beaker and turn the stir setting on to high.</div>
		</li>
		<li data-sub-note-item="1-14">
		<div class="lab-step">Connect the data acquisition system to the current probe and allow the data acquisition system to sense the probe. It should return a reading in amps. Change the rate to two scans per min and the duration to 5 min.</div>
		</li>
		<li data-sub-note-item="1-15">
		<div class="lab-step">Place the brass key in the beaker. Hang it off the side of the beaker so that the key is almost completely submerged but does not touch the magnetic stir bar. <strong>Note: </strong>The copper wire should not be in the solution.</div>
		</li>
		<li data-sub-note-item="1-16">
		<div class="lab-step">Place the copper electrode in the beaker, bending it so that it hangs over the edge of the beaker. Ensure that it is not touching the stir bar or the brass key.</div>
		</li>
		<li data-sub-note-item="1-17">
		<div class="lab-step">Start the scan and let it collect data for 5 min. This will act as a test run to make sure plating occurs on the brass key.</div>
		</li>
		<li data-sub-note-item="1-18">
		<div class="lab-step">After the scan ends, remove the key and copper electrode. The copper plating on the brass key should be evident. If it is not visible, check your circuit to make sure that the battery is connected in the correct orientation.</div>
		</li>
		<li data-sub-note-item="1-19">
		<div class="lab-step">Once you have completed a successful 5-min plating, disconnect the key and copper electrode from the wiring. Remove the copper wire from the key and rinse the key and copper electrode with water and then acetone. Lay them on a paper towel to dry.</div>
		</li>
		<li data-sub-note-item="1-20">
		<div class="lab-step">Measure the masses of the key and the copper electrode and record them in your lab notebook.</div>
		</li>
		<li data-sub-note-item="1-21">
		<div class="lab-step">Reconnect the key and copper electrode and place them back in the solution like before. Restart the run on the data acquisition system, making sure that the rate is set to two scans per min. With the duration set to 30 min, allow the electroplating process to run.</div>
		</li>
		<li data-sub-note-item="1-22">
		<div class="lab-step">After the scan is complete, remove the electrode and key from the solution, disconnect them from the wires, and rinse them with water and then acetone. Allow them to dry on a paper towel, then weigh them and record their masses in your notebook.</div>
		</li>
		<li data-sub-note-item="1-23">
		<div class="lab-step">Reassemble the setup and repeat the electroplating for a second 30-min trial. When the scan is complete, remove the key and copper electrode, rinse them like before, and record their mass.</div>
		</li>
		<li data-sub-note-item="1-24">
		<div class="lab-step">Save the recorded data as a text file on a flash drive.</div>
		</li>
		<li data-sub-note-item="1-25">
		<div class="lab-step">To clean up, turn the stir setting off and remove the stir bar from the solution using forceps. Dispose of the acetone in the organic waste container provided by your instructor. The copper sulfate solution can be reused for future labs, so pour the concentrated copper sulfate back into the carboy.</div>
		</li>
		<li data-sub-note-item="1-26">
		<div class="lab-step">Rinse all of your glassware with water and return it to the instructor.</div>
		</li>
	</ul>
	</li>
	<li data-note-item="2" data-parent-collapse="">Results<button class="expand">Expand</button>
	<ul class="lab-items">
		<li data-sub-note-item="2-1">
		<div class="lab-step">First, calculate the total charge Q that flowed through the system during the different trials. One coulomb is the quantity of electricity flowing through a wire carrying 1 ampere of current in 1 s, thus Q = I x t.</div>
		</li>
		<li data-sub-note-item="2-2">
		<div class="lab-step">Review the current probe data for the first 5-min electroplating trial.<strong> Note: </strong>If the current dropped to 0 or close to 0 at the end of the trial, then the electrons stopped flowing from the copper electrode to the key. Only use the values recorded before the drop in current occurred. If the current drop to 0 early in the plating process, repeat the trial.</div>
		</li>
		<li data-sub-note-item="2-3">
		<div class="lab-step">The current varies over time, so calculate the average current, I.
		<h4><strong>Table 2: Moles of Electrons Transferred</strong></h4>
		<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
			<tbody>
				<tr>
					<td style="text-align: center;"><strong>Trial</strong></td>
					<td style="text-align: center;"><strong>Time (s) </strong></td>
					<td style="text-align: center;"><strong>Current<sub>average</sub> (A) </strong></td>
					<td style="text-align: center;"><strong>Total charge (C) </strong></td>
					<td style="text-align: center;"><strong>Moles (e?) </strong></td>
				</tr>
				<tr>
					<td style="text-align: center;">5 min</td>
					<td></td>
					<td></td>
					<td></td>
					<td></td>
				</tr>
				<tr>
					<td style="text-align: center;">1<sup>st</sup> 30 min</td>
					<td></td>
					<td></td>
					<td></td>
					<td></td>
				</tr>
				<tr>
					<td style="text-align: center;">2<sup>nd</sup> 30 min</td>
					<td></td>
					<td></td>
					<td></td>
					<td></td>
				</tr>
				<tr>
					<td style="text-align: center;">Total</td>
					<td></td>
					<td></td>
					<td></td>
					<td></td>
				</tr>
			</tbody>
		</table>
		<a href="https://www-jove-com.bdigitaluss.remotexs.co/CDNSource/lm/labs/53/Table_2._Moles_of_Electrons_Transferred.xlsx" target="_blank">Click Here to download Table 2</a></div>
		</li>
		<li data-sub-note-item="2-4">
		<div class="lab-step">Use the average current over the total time to determine the total charge transferred during electroplating, Q. About 20 coulombs were transferred during the 5-min trial, and between 110 and 120 coulombs were transferred during each 30-min trial. The total charge transferred over the entire 65-min electroplating process was about 250 coulombs.</div>
		</li>
		<li data-sub-note-item="2-5">
		<div class="lab-step">Use the total charge transferred to calculate the moles of electrons plated during each trial. The moles of electrons plated equals the total charge transferred divided by the Faraday constant. The Faraday constant represents the magnitude of electric charge per mole of electrons and is determined by multiplying the charge of an electron by Avogadro&#39;s constant.</div>
		</li>
		<li data-sub-note-item="2-6">
		<div class="lab-step">Determine the moles of electrons that were transferred for the 5-min and 30-min trials.</div>
		</li>
		<li data-sub-note-item="2-7">
		<div class="lab-step">Calculate the moles of copper that were plated on the key after each trial. Similarly, determine the moles of copper lost from the copper sheet electrode.</div>
		</li>
		<li data-sub-note-item="2-8">
		<div class="lab-step">Compare the moles of copper that were lost from the electrode to the amount that was plated to the brass key. The numbers should be close.</div>
		</li>
		<li data-sub-note-item="2-9">
		<div class="lab-step">Check to see if these values match what is expected based on the number of moles of electrons that were transferred. The reduction of 1 mole of copper(2+) ions requires 2 moles of electrons to produce 1 mole of solid copper.</div>
		</li>
	</ul>
	</li>
</ol>

Electrolytic Cells: Construction and Electroplating - Procedure

전해 전지

Source: Smaa Koraym at Johns Hopkins University, MD, USA

	Electrolytic CellsExpand
	In this experiment, you will be assembling an electrolytic cell to ...

Basic Organic Chemistry Techniques

<p>Source: Lara Al Hariri and Ahmed Basabrain at the University of Massachusetts Amherst, MA, USA</p>
<ol class="note-items">
	<li data-note-item="1" data-parent-collapse="">Synthesis of Benzoic Acid<button class="expand">Expand</button>
	<p>In this lab, you&#39;ll learn several important techniques that you&#39;ll use throughout this class. This includes measuring the mass or volume of reactants and products, methods of heating and cooling reaction mixtures, proper selection and handling of glassware, and separating solids and liquids by vacuum filtration. First, you&#39;ll synthesize benzoic acid by protonating sodium benzoate with hydrochloric acid, or HCl, using water as the solvent. Sodium benzoate is very soluble in water, but benzoic acid is not, so you can filter the solid product out of the solution.</p>
	<p>You&#39;ll use vacuum filtration, which is used for powdery solids, to filter out the benzoic acid. Benzoic acid is less soluble in water at lower temperatures, so you&#39;ll collect more product if you cool the reaction solution before you filter it. When you do this lab, remember that HCl is toxic and a strong acid. It&#39;s always best to work with strong acids and organic solvents in a fume hood. If you spill any HCl, follow your lab&#39;s procedures for neutralizing and cleaning up strong acids.</p>
	<ul class="lab-items">
		<li data-sub-note-item="1-3">
		<div class="lab-step">Put on a lab coat, safety glasses, and nitrile gloves. Change your gloves if you get acid or organic solvent on them.</div>
		</li>
		<li data-sub-note-item="1-4">
		<div class="lab-step">Bring a clean 50-mL beaker and your lab notebook to the balance, and then tare a clean empty weighing boat on the balance.</div>
		</li>
		<li data-sub-note-item="1-5">
		<div class="lab-step">Use a clean spatula to measure out ~2 g of sodium benzoate.<strong> Note:</strong> Stay between 1.9 and 2.1 g.</div>
		</li>
		<li data-sub-note-item="1-6">
		<div class="lab-step">Dispose of any extra sodium benzoate into the appropriate waste container. Close the bottle of sodium benzoate when you&#39;re done with it.</div>
		</li>
		<li data-sub-note-item="1-7">
		<div class="lab-step">Write down the mass of sodium benzoate and pour it into your beaker. Clean the spatula with a lab wipe so that it can be used again and return to your fume hood.
		<h4><strong>Table 1: Reaction yield of benzoic acid</strong></h4>
		<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
			<tbody>
				<tr>
					<td style="text-align: center;"><strong>Mass of sodium<br />
					benzoate (g)</strong></td>
					<td style="text-align: center;"><strong>Moles of sodium<br />
					benzoate</strong></td>
					<td style="text-align: center;"><strong>Volume of<br />
					HCl (mL)</strong></td>
					<td style="text-align: center;"><strong>Moles of<br />
					HCl</strong></td>
					<td style="text-align: center;"><strong>Moles of benzoic<br />
					acid</strong></td>
					<td style="text-align: center;"><strong>Mass of benzoic<br />
					acid (g)</strong></td>
				</tr>
				<tr>
					<td></td>
					<td></td>
					<td></td>
					<td></td>
					<td></td>
					<td></td>
				</tr>
				<tr>
					<td></td>
					<td></td>
					<td></td>
					<td></td>
					<td><strong>Theoretical yield</strong></td>
					<td></td>
				</tr>
				<tr>
					<td style="text-align: center;">-</td>
					<td style="text-align: center;">-</td>
					<td style="text-align: center;">-</td>
					<td style="text-align: center;">-</td>
					<td><strong>Percent yield</strong></td>
					<td></td>
				</tr>
			</tbody>
		</table>
		<a href="https://www-jove-com.bdigitaluss.remotexs.co/CDNSource/lm/labs/56/Table_1._Reaction_yield_of_benzoic_acid.xlsx" target="_blank">Click Here to download Table 1</a></div>
		</li>
		<li data-sub-note-item="1-8">
		<div class="lab-step">Get a clean 10-mL graduated cylinder and measure 10 mL of deionized water. Pour the water into the beaker of sodium benzoate. Stir the solution with a glass rod until the sodium benzoate has completely dissolved.</div>
		</li>
		<li data-sub-note-item="1-9">
		<div class="lab-step">Obtain a clean 5-mL graduated cylinder and measure 5 mL of 3 M HCl. <strong>Note: </strong>If you pour too much, use a Pasteur pipette to transfer the excess to a small beaker labeled &#8216;acid waste&#8217;. Close the bottle and put it back when you&#39;re done.</div>
		</li>
		<li data-sub-note-item="1-10">
		<div class="lab-step">Use a clean Pasteur pipette to draw up a small amount of HCl from your graduated cylinder. Start adding the HCl to the sodium benzoate solution at a rate of about one drop every 6 seconds or 10 drops/min. Stir the solution frequently with the glass rod. This should take about 10 min. <strong>Note:</strong> As you add more HCl, you&#39;ll start to see benzoic acid precipitating from the solution.</div>
		</li>
		<li data-sub-note-item="1-11">
		<div class="lab-step">When you are done, fill a 600-mL beaker about halfway with crushed ice and add tap water to just fill the spaces between the ice to make an ice bath.</div>
		</li>
		<li data-sub-note-item="1-12">
		<div class="lab-step">Place the ice bath by a lab stand in your fume hood and use a medium clamp to hold the reaction beaker in the bath. Make sure that the surface of the solution is below the ice.</div>
		</li>
		<li data-sub-note-item="1-13">
		<div class="lab-step">Clamp a thermometer in the reaction solution.</div>
		</li>
		<li data-sub-note-item="1-14">
		<div class="lab-step">While the reaction cools, obtain 25 mL of deionized water in a 50-mL graduated cylinder. Place the graduated cylinder in a 600-mL beaker and pack ice around it to cool the water.</div>
		</li>
		<li data-sub-note-item="1-15">
		<div class="lab-step">Once the reaction solution reaches 10 &#176;C, it&#39;s ready to be filtered. Set up another lab stand and obtain a clean 250-mL filter flask. Clamp the flask upright on the lab stand.</div>
		</li>
		<li data-sub-note-item="1-16">
		<div class="lab-step">Ensure that your vacuum tubing is connected to the vacuum source, and then carefully push the free end of the tubing onto the barbed arm of the flask.</div>
		</li>
		<li data-sub-note-item="1-17">
		<div class="lab-step">Place a rubber adapter and a B&#252;chner funnel in the mouth of the flask. Confirm that the reaction solution has reached 10 &#176;C and remove the thermometer from the beaker.</div>
		</li>
		<li data-sub-note-item="1-18">
		<div class="lab-step">Obtain a piece of circular filter paper and place it in the B&#252;chner funnel so that the small holes are completely covered.</div>
		</li>
		<li data-sub-note-item="1-19">
		<div class="lab-step">Get a new Pasteur pipette, and use a few drops of cold deionized water to wet the filter paper. <strong>Note: </strong>This helps keep the filter paper in place when you pour the solution into the funnel.</div>
		</li>
		<li data-sub-note-item="1-20">
		<div class="lab-step">Open the vacuum line part way to reduce the pressure in the flask.</div>
		</li>
		<li data-sub-note-item="1-21">
		<div class="lab-step">Remove the beaker from the ice bath, stir the solution well with the glass rod until the solid is swirling around in the liquid, and then slowly pour it onto the filter paper. <strong>Note:</strong> If the liquid does not move quickly through the funnel, make sure that there are no gaps between the funnel, adapter, and flask, and then gradually open the vacuum until the liquid rapidly flows into the flask.</div>
		</li>
		<li data-sub-note-item="1-22">
		<div class="lab-step">Use a clean Pasteur pipette to rinse the inner walls of the beaker with ~10 mL of cold deionized water and pour the rinse into the funnel. Pour the rest of the cold deionized water over the benzoic acid on the filter to wash it. <strong>Note:</strong> This is an important step that removes impurities, side products, and unreacted compounds.</div>
		</li>
		<li data-sub-note-item="1-23">
		<div class="lab-step">Leave the benzoic acid in the funnel with the vacuum running until it is completely dry. <strong>Note: </strong>This usually takes ~2 h, so let&#39;s continue to the second half of the lab in the meantime.</div>
		</li>
	</ul>
	</li>
	<li data-note-item="2" data-parent-collapse="">Refluxing Tetrahydrofuran (THF) and Measuring Product Mass<button class="expand">Expand</button>
	<p>While your benzoic acid dries, you&#39;ll practice refluxing tetrahydrofuran, or THF, which has a boiling point of 66 &#176;C. THF is volatile, flammable, and an irritant, so avoid letting it touch your skin and always work with it in a fume hood. Refluxing is a technique that constantly condenses the vapor and returns it to the flask. This allows reactions to be performed at high temperatures, such as at the solvent&#39;s boiling point, without losing the solvent to evaporation.</p>
	<p>Refluxing is achieved with a special piece of glassware called a condenser, which is attached directly to your flask. The condenser is cooled with water flowing through the outer chamber. As vapor rises through the condenser, it loses heat to the cool walls, condenses, and drips back into the flask.</p>
	<p>Refluxing is usually performed in a round-bottom flask. These flasks must be heated in a heating bath or with specialized equipment, but they provide more even heating than an Erlenmeyer flask or beaker as a result. Water baths are typically used for experiments performed below 80 &#8211; 100 &#176;C.</p>
	<ul class="lab-items">
		<li data-sub-note-item="2-4">
		<div class="lab-step">Set up the glassware and equipment for reflux. Place a lab jack by your available lab stand and set a stirring hotplate on top of it. Clamp a 50-mL round-bottom flask at least 12 cm above the hotplate.</div>
		</li>
		<li data-sub-note-item="2-5">
		<div class="lab-step">Bring a 50-mL graduated cylinder to the solvent hood and measure 25 mL of THF. If you pour too much, label a small beaker &#8216;organic waste&#8217; and pipette the excess into that. Remember to cap the bottle when you&#39;re done.</div>
		</li>
		<li data-sub-note-item="2-6">
		<div class="lab-step">Carefully pour the THF into the round-bottom flask, clean up any spills with a lab wipe or paper towel, and add a small oblong stir bar to the flask.</div>
		</li>
		<li data-sub-note-item="2-7">
		<div class="lab-step">Position a medium clamp ~20 cm above the flask. Obtain a condenser and apply vacuum grease to the lower ground-glass joint.</div>
		</li>
		<li data-sub-note-item="2-8">
		<div class="lab-step">Fit the condenser into the flask and rotate them in opposite directions until the vacuum grease is evenly spread between the two ground-glass surfaces.</div>
		</li>
		<li data-sub-note-item="2-9">
		<div class="lab-step">Clamp the condenser in place and use a lab wipe to remove excess grease from the connection between the two pieces of glassware.</div>
		</li>
		<li data-sub-note-item="2-10">
		<div class="lab-step">Attach rubber tubing to each of the ports on the condenser. Place the free end of the tubing connected to the top port, which is the outlet, in the drain. Connect the free end of the tubing from the bottom port, which is the inlet, to the waterline.</div>
		</li>
		<li data-sub-note-item="2-11">
		<div class="lab-step">Fill a 250-mL beaker with ~200 mL of tap water and place this water bath on the hotplate. Use the lab jack to raise the bath until the water level is about 2/3 of the way up the spherical part of the flask. This will ensure the THF heats evenly.</div>
		</li>
		<li data-sub-note-item="2-12">
		<div class="lab-step">Secure a thermometer (range 0 &#8211; 100 &#176;C) in the bath using the thermometer clamp.</div>
		</li>
		<li data-sub-note-item="2-13">
		<div class="lab-step">Slowly open the water tap, watch the condenser for leaks as it fills, and confirm that the water is flowing into the drain.</div>
		</li>
		<li data-sub-note-item="2-14">
		<div class="lab-step">Slowly turn up the magnetic stirrer until the THF is stirring well. If the stir bar bounces around, turn down the stir motor and try again more slowly.</div>
		</li>
		<li data-sub-note-item="2-15">
		<div class="lab-step">Start heating the water bath to about 70 &#176;C until the THF starts to boil. <strong>Note: </strong>You&#39;ll see vapor condensing in the lower part of the condenser).</div>
		</li>
		<li data-sub-note-item="2-16">
		<div class="lab-step">Monitor the refluxing THF for 10 min. <strong>Note:</strong> Turn down the heat if the bath goes above 70 &#176;C or if vapor leaves the condenser.</div>
		</li>
		<li data-sub-note-item="2-17">
		<div class="lab-step">After 10 min, remove the thermometer and turn off the heat and the stir motor. Carefully lower the lab jack until the flask is clear of the water bath. Wait at least 10 more min for the setup to cool, then unplug and remove the hotplate.</div>
		</li>
		<li data-sub-note-item="2-18">
		<div class="lab-step">Turn off the water tap, unclamp the condenser, and carefully detach it from the flask. Tilt the condenser until most of the water has flowed through the outlet tubing into the drain. Then, disconnect the inlet tubing from the condenser and let the remaining water flow into the drain. Do the same for the outlet tubing.</div>
		</li>
		<li data-sub-note-item="2-19">
		<div class="lab-step">Use lab wipes to remove the vacuum grease from the condenser and the flask, then retrieve the stir bar from the flask.</div>
		</li>
		<li data-sub-note-item="2-20">
		<div class="lab-step">Bring the flask to the waste hood and empty it into the non-halogenated organic waste container. Pour any excess HCl or THF into the acid and organic wastes, respectively. Empty the ice and water baths into the sink and rinse the beakers with tap water.</div>
		</li>
		<li data-sub-note-item="2-21">
		<div class="lab-step">Clean most of your other glassware while the benzoic acid from earlier finishes drying according to your lab&#8217;s standard practices. Usually, you&#39;ll rinse your glassware both with an organic solvent, like acetone, and with detergent and deionized water. <strong>Note:</strong> Your lab may have specific procedures for glassware used with acids. If so, follow that procedure to clean the graduated cylinder used with HCl and your acid waste beaker, if applicable.</div>
		</li>
		<li data-sub-note-item="2-22">
		<div class="lab-step">Remove the reusable pipette bulbs and dispose of your pipettes in the glass waste container. Throw out used lab wipes and paper towels in the lab trash.</div>
		</li>
		<li data-sub-note-item="2-23">
		<div class="lab-step">Check on your benzoic acid. If it is dry, turn off the vacuum and break the vacuum seal by disconnecting the tubing from the filter flask. Gently place the funnel in it 250-mL beaker and bring it and your lab notebook to the balance.</div>
		</li>
		<li data-sub-note-item="2-24">
		<div class="lab-step">Tare a weighing boat and use a clean spatula to transfer the product to the weighing boat. Record the mass of your product in your lab notebook.</div>
		</li>
		<li data-sub-note-item="2-25">
		<div class="lab-step">Then, put the product in the lab trash and wipe off the spatula. Dispose of the filtrate in the aqueous waste container.</div>
		</li>
		<li data-sub-note-item="2-26">
		<div class="lab-step">Clean the rest of your glassware, throw out the filter paper and other waste in the lab trash, and put away your lab equipment. Lastly, clean the floor of your fume hood with a damp paper towel.</div>
		</li>
	</ul>
	</li>
	<li data-note-item="3" data-parent-collapse="">Results<button class="expand">Expand</button>
	<ul class="lab-items">
		<li data-sub-note-item="3-1">
		<div class="lab-step">Calculate the reaction yield for the protonation of sodium benzoate. Identify the reagent that the reaction runs out of first, which is called the limiting reagent.</div>
		</li>
		<li data-sub-note-item="3-2">
		<div class="lab-step">Calculate the number of moles of sodium benzoate and HCl that you used. <strong>Note:</strong> You used about 0.014 moles of sodium benzoate and 0.015 moles of HCl. Thus, the maximum yield of benzoic acid is equal to the starting amount of sodium benzoate in moles.</div>
		</li>
		<li data-sub-note-item="3-3">
		<div class="lab-step">Convert the mass of your benzoic acid to moles, divide that by the moles of sodium benzoate that you used, and multiply it by 100 to get the percent yield. <strong>Note:</strong> The recovered yield for this reaction is usually between 80% and 98% because a small amount of benzoic acid stays in solution. If the yield is above 100%, then it&#39;s likely that your product was still wet when you weighed it. Impurities, unreacted compounds, and products of side reactions can also affect the accuracy of yield calculations.</div>
		</li>
	</ul>
	</li>
</ol>

기본 유기 화학 기법

Source: Lara Al Hariri and Ahmed Basabrain at the University of Massachusetts Amherst, MA, USA

	Synthesis of Benzoic AcidExpand
	In this lab, you&#39;ll ...

Melting Points

<p>Source: Lara Al Hariri and Ahmed Basabrain at the University of Massachusetts Amherst, MA, USA</p>
<ol class="note-items">
	<li data-note-item="1" data-parent-collapse="">Determining the Melting Points of Naphthalene, Urea, and an Unknown Mixture<button class="expand">Expand</button>
	<p>In this experiment, you will measure the melting point range of two known substances, naphthalene and urea, by observing the melting phenomenon during heating. You&#39;ll then analyze a mixture of urea and an unknown substance to observe how the unknown impurity affects the melting point range.</p>
	<ul class="lab-items">
		<li data-sub-note-item="1-2">
		<div class="lab-step">Put on a lab coat, splash-proof safety glasses, and nitrile gloves.</div>
		</li>
		<li data-sub-note-item="1-3">
		<div class="lab-step">Weigh ~1 mg of naphthalene using the analytical balance, and carefully, bring it back to your bench.</div>
		</li>
		<li data-sub-note-item="1-4">
		<div class="lab-step">Transfer the naphthalene onto a watch glass, and then crush it using the metal spatula until it becomes a fine powder.</div>
		</li>
		<li data-sub-note-item="1-5">
		<div class="lab-step">Carefully pick up one capillary tube and tap the open end on the powder to force some of the solid into the tube.</div>
		</li>
		<li data-sub-note-item="1-6">
		<div class="lab-step">Obtain a long glass tube from the common bench and hold it upright over your bench. Pick up the capillary with the open end upward and then drop it through the glass tube. Allow the capillary to bounce off the benchtop to pack the solid at the bottom.</div>
		</li>
		<li data-sub-note-item="1-7">
		<div class="lab-step">Retrieve the capillary and tap its open end on the naphthalene powder again to force more of it into the capillary. Continue loading naphthalene into the capillary and dropping it through the glass tube until 1 &#8211; 2 mL of powder is packed at the bottom of the capillary.</div>
		</li>
		<li data-sub-note-item="1-8">
		<div class="lab-step">Use a rubber band to attach the capillary to a digital thermometer, with the bottom of the capillary just above the bottom of the thermometer. <strong>Note:</strong> Make sure that the rubber band is at least 8 &#8211; 9 cm above the solid in the capillary.</div>
		</li>
		<li data-sub-note-item="1-9">
		<div class="lab-step">Set up a stirring hotplate and a lab stand in a fume hood and clamp the thermometer above the hotplate.</div>
		</li>
		<li data-sub-note-item="1-10">
		<div class="lab-step">Place the provided mineral oil bath on the hotplate and add a magnetic stir bar. Start stirring the bath at a moderate speed over low heat.</div>
		</li>
		<li data-sub-note-item="1-11">
		<div class="lab-step">Lower the thermometer and capillary setup into the oil bath until the sample is about 5 cm deep in the bath. <strong>Note:</strong> Make sure that the rubber band is above the mineral oil.</div>
		</li>
		<li data-sub-note-item="1-12">
		<div class="lab-step">Increase the hotplate temperature to 60&#176;C, which is about 20&#176; below the melting point of naphthalene in the literature.<strong> Note:</strong> It will take about 10 min for the entire oil bath to reach the same temperature as the hotplate.</div>
		</li>
		<li data-sub-note-item="1-13">
		<div class="lab-step">Once the bath reaches 60&#176;C, heat it to 75&#176;C at a rate of 5&#176;C/min. When the bath is close to the melting point of naphthalene (80&#176;C), heat the bath by 1 &#8211; 2 &#176;C/min while carefully observing the solid in the capillary.</div>
		</li>
		<li data-sub-note-item="1-14">
		<div class="lab-step">At the first drop of liquid in the capillary, record the temperature of the oil bath. Keep watching the capillary tube as you slowly increase the temperature. Record the temperature when the last piece of solid melts.
		<h4><strong>Table 1: Melting Points of Naphthalene, Urea, and an Unknown Mixture</strong></h4>
		<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
			<tbody>
				<tr>
					<td></td>
					<td colspan="2" style="text-align: center;"><strong>Melting point temperature (&#176;C)</strong></td>
				</tr>
				<tr>
					<td><strong>Substance</strong></td>
					<td style="text-align: center;"><strong>Start</strong></td>
					<td style="text-align: center;"><strong>End</strong></td>
				</tr>
				<tr>
					<td>Napthalene</td>
					<td></td>
					<td></td>
				</tr>
				<tr>
					<td>Urea</td>
					<td></td>
					<td></td>
				</tr>
				<tr>
					<td>Urea + Unknown (trial 1)</td>
					<td></td>
					<td></td>
				</tr>
				<tr>
					<td>Urea + Unknown (trial 2)</td>
					<td></td>
					<td></td>
				</tr>
			</tbody>
		</table>
		<a href="https://www-jove-com.bdigitaluss.remotexs.co/CDNSource/lm/labs/66/Table_1._Melting_points_of_naphthalene,_urea,_and_an_unknown_mixture.xlsx" target="_blank">Click Here to download Table 1</a></div>
		</li>
		<li data-sub-note-item="1-15">
		<div class="lab-step">Carefully remove the capillary and thermometer from the oil bath and set them aside to cool.</div>
		</li>
		<li data-sub-note-item="1-16">
		<div class="lab-step">Weigh roughly 1 mg of urea and transfer it to a clean watch glass. Crush the urea to a powder. Load the powder into a capillary tube as before.</div>
		</li>
		<li data-sub-note-item="1-17">
		<div class="lab-step">Attach the capillary to the thermometer with the rubber band. Heat the oil bath to 110&#176;C, which is about 20&#176; below the reported melting point of 132&#176;C for urea.</div>
		</li>
		<li data-sub-note-item="1-18">
		<div class="lab-step">Insert the thermometer and capillary tube into the oil bath. Heat the bath to about 125&#176;C at 5&#176;C/min while watching the capillary.</div>
		</li>
		<li data-sub-note-item="1-19">
		<div class="lab-step">When the bath reaches 125&#176;C, heat the bath by 1 &#8211; 2&#176;C /min. Record the temperature when the first drop of liquid appears and when the last bit of solid melts.</div>
		</li>
		<li data-sub-note-item="1-20">
		<div class="lab-step">Turn off the hotplate and remove the capillary and thermometer from the oil bath to allow them to cool.</div>
		</li>
		<li data-sub-note-item="1-21">
		<div class="lab-step">Test the sample of urea mixed with an unknown impurity, which was prepared by your instructor. Perform two runs of this sample, so weigh 2 mg of the sample on the balance and transfer it to a watch glass.</div>
		</li>
		<li data-sub-note-item="1-22">
		<div class="lab-step">Crush the sample to powder and load two capillaries by tapping them on the powder and dropping them through the glass tube like before.</div>
		</li>
		<li data-sub-note-item="1-23">
		<div class="lab-step">Once the oil bath has cooled to at least 80&#176;C, turn on the stir motor and set the hotplate to 80&#176;C. Attach one of the loaded capillaries to the thermometer and clamp them in the oil bath.</div>
		</li>
		<li data-sub-note-item="1-24">
		<div class="lab-step">In the first test run, increase the temperature by 10&#176;C/min until the sample has melted to determine the rough melting point range. Record the temperature when you see the first drop of liquid form and the last drop of liquid form to determine the rough melting point range.</div>
		</li>
		<li data-sub-note-item="1-25">
		<div class="lab-step">Turn off the hotplate and allow it to cool. Once the oil bath has cooled to at least 80&#176;C, attach the second sample to the thermometer and clamp them in the bath. Turn the stir motor back on and set the hotplate to 80&#176;C.</div>
		</li>
		<li data-sub-note-item="1-26">
		<div class="lab-step">For the second test, heat the bath by 5&#176;C/min until you are close to the rough melting point range, and then continue heating by 1 &#8211; 2&#176;C/min to accurately capture the melting point range.</div>
		</li>
		<li data-sub-note-item="1-27">
		<div class="lab-step">When you have finished measuring the melting point of the urea mixed with the unknown substance, turn off the hotplate and detach the capillary tube from the thermometer. Dispose of your capillary tubes in the glass waste container.</div>
		</li>
		<li data-sub-note-item="1-28">
		<div class="lab-step">Return the mineral oil to your instructor, and clean all of your glassware using detergent and water.</div>
		</li>
	</ul>
	</li>
	<li data-note-item="2" data-parent-collapse="">Results<button class="expand">Expand</button>
	<ul class="lab-items">
		<li data-sub-note-item="2-1">
		<div class="lab-step">First, look at the melting point range of naphthalene. These differences may be caused by experimental errors, such as heating the sample too quickly, or by impurities in the sample.</div>
		</li>
		<li data-sub-note-item="2-2">
		<div class="lab-step">Next, check the results for the pure urea sample. Why is urea&#39;s melting point so much higher than naphthalene&#39;s? Looking at the structure of naphthalene, the intermolecular forces must be primarily London dispersion forces. Urea is capable of hydrogen bonding, so the intermolecular forces in solid urea are much stronger than the forces in solid naphthalene.</div>
		</li>
		<li data-sub-note-item="2-3">
		<div class="lab-step">Finally, look at the results from the urea sample with the impurity. The melting point range should be broader and lower than the range for pure urea because of freezing point depression. As expected, the melting point range obtained was 127 &#8211; 130&#176;C, which is lower than the range for pure urea.</div>
		</li>
	</ul>
	</li>
</ol>

Determination of Melting Points - Procedure

녹는 점

Source: Lara Al Hariri and Ahmed Basabrain at the University of Massachusetts Amherst, MA, USA

	Determining the Melting Points of Naphthalene, Urea, and ...

Boiling Points

<p>Source: Lara Al Hariri and Ahmed Basabrain at the University of Massachusetts Amherst, MA, USA</p>
<ol class="note-items">
	<li data-note-item="1" data-parent-collapse="">Boiling point determination of acetone and ethanol<button class="expand">Expand</button>
	<p>The temperature at which a pure organic substance changes from the liquid phase to the gas phase is known as the boiling point. A liquid&#39;s boiling point can be determined using the capillary method, where an inverted capillary is placed in the liquid of interest and the liquid is heated. As the temperature increases, the air in the capillary escapes and is replaced by the vapor of the liquid. The vapor pressure in the capillary increases with temperature. Once it exceeds the atmospheric pressure, the vapor escapes the capillary in a stream of bubbles. When the heat is removed, the liquid cools, and the vapor pressure in the capillary decreases. When the vapor pressure reaches the atmospheric pressure, the liquid begins to fill the capillary. The temperature at which this occurs is the boiling point.</p>
	<ul class="lab-items">
		<li data-sub-note-item="1-2">
		<div class="lab-step">Put on a lab coat, splash-proof safety glasses, and nitrile gloves. This experiment must be conducted in a hood.</div>
		</li>
		<li data-sub-note-item="1-3">
		<div class="lab-step">Attach a small test tube to the thermometer using a rubber band, and secure the thermometer in the clamp.</div>
		</li>
		<li data-sub-note-item="1-4">
		<div class="lab-step">Obtain acetone and bring it back to your hood. Using your glass pipette and a bulb, measure 1 mL of acetone and transfer it into the small test tube.</div>
		</li>
		<li data-sub-note-item="1-5">
		<div class="lab-step">Align the thermometer end so that it is level with the acetone in the test tube, keeping them close to each other. Invert a capillary tube and place it in the test tube so that the open end is facing downwards.</div>
		</li>
		<li data-sub-note-item="1-6">
		<div class="lab-step">Use a 250-mL beaker to create a water bath. Add approximately 180 mL of water to the beaker, and place it on the hotplate.</div>
		</li>
		<li data-sub-note-item="1-7">
		<div class="lab-step">Lower the thermometer and test tube into the water bath. Turn on the hotplate to the lowest setting, about 30&#176;C.</div>
		</li>
		<li data-sub-note-item="1-8">
		<div class="lab-step">Slowly increase the temperature on the hotplate by 10 &#8211; 20&#176;C every 10 min, and closely observe the liquid in the test tube. When you start to see occasional bubbles in the liquid, increase the heat setting by only 5&#176;C every 10 min.</div>
		</li>
		<li data-sub-note-item="1-9">
		<div class="lab-step">Closely observe the capillary tube inside the test tube. Report the temperature at which a rapid and continuous stream of bubbles comes out of the capillary.
		<h4><strong>Table 1: Boiling point of acetone and ethanol</strong></h4>
		<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
			<tbody>
				<tr>
					<td></td>
					<td colspan="2" style="text-align: center;"><strong>Boiling point temperature (&#176;C)</strong></td>
				</tr>
				<tr>
					<td></td>
					<td style="text-align: center;"><strong>Bubbles </strong></td>
					<td style="text-align: center;"><strong>Liquid in capillary </strong></td>
				</tr>
				<tr>
					<td>Acetone</td>
					<td></td>
					<td></td>
				</tr>
				<tr>
					<td>Ethanol</td>
					<td></td>
					<td></td>
				</tr>
			</tbody>
		</table>
		<a href="https://www-jove-com.bdigitaluss.remotexs.co/CDNSource/lm/labs/57/Table_1._Boiling_point_of_acetone_and_ethanol.xlsx" target="_blank">Click Here to download Table 1</a></div>
		</li>
		<li data-sub-note-item="1-10">
		<div class="lab-step">Turn off the heat and allow the water bath to cool. Keep observing the capillary as the production of bubbles decreases until no bubbles emerge from the capillary. The liquid will start to rise in the capillary. Record the temperature at which this occurs.</div>
		</li>
		<li data-sub-note-item="1-11">
		<div class="lab-step">Label a clean 25-mL beaker as &#8216;organic waste&#8217;. Once the water bath has cooled to about 35&#176;C, remove the thermometer and test tube from the bath. Detach the test tube from the thermometer and pour the acetone into the waste beaker.</div>
		</li>
		<li data-sub-note-item="1-12">
		<div class="lab-step">Use a clean test tube and capillary and repeat the experiment using 1 mL of ethanol.</div>
		</li>
		<li data-sub-note-item="1-13">
		<div class="lab-step">After you have measured the boiling point of ethanol, allow the water bath to cool. Once it has cooled sufficiently, remove the test tube and thermometer from the water bath, detach the test tube from the thermometer, and pour the ethanol into the organic waste beaker.</div>
		</li>
		<li data-sub-note-item="1-14">
		<div class="lab-step">Dispose of the water from the water bath down the sink and place the capillaries and test tubes in the glass disposal. Dispose of the organic waste in the container provided by your instructor.</div>
		</li>
		<li data-sub-note-item="1-15">
		<div class="lab-step">Wash all of your glassware with detergent and water.</div>
		</li>
	</ul>
	</li>
	<li data-note-item="2" data-parent-collapse="">Results<button class="expand">Expand</button>
	<p>In this experiment, we measured the boiling point of acetone to be 56&#176;C, which compares well to the reported value. Similarly, the boiling point of ethanol was measured to be 78&#176;C. Errors in the boiling point measurement can be attributed to many experimental errors, such as heating the water bath too rapidly, or poor alignment of the thermometer and sample.</p>
	<p>The boiling point of an organic substance is directly related to its structure, where stronger intramolecular forces result in a higher boiling point as molecules are able to hold onto each other and remain in the liquid phase longer. The higher boiling point for ethanol is observed due to the OH structure that causes hydrogen bonding between the molecules. Acetone has a polar CO double bond, which results in dipole-dipole forces. Since hydrogen bonding is stronger than dipole-dipole forces, ethanol has a higher boiling point.</p>
	<p>Additionally, ethanol has a lower molecular weight than acetone. However, molecular weight has less of an impact on the boiling point than the molecular structure. For example, butane is a gas at room temperature and pressure, as it has a boiling point lower than 25&#176;C. Ethanol has a slightly lower molecular mass than butane, but it is liquid at room temperature and, therefore, has a boiling point higher than room temperature. This is due to the hydrogen bonding between the ethanol molecules, which is stronger than the van der Waals forces between the butane molecules.</p>
	<ul class="lab-items">
	</ul>
	</li>
</ol>

Determination of Boiling Points by Capillary Method - Procedure

끓는점

Source: Lara Al Hariri and Ahmed Basabrain at the University of Massachusetts Amherst, MA, USA

	Boiling point determination of acetone and ethanolExpand
	...

Recrystallization

<p>Source: Lara Al Hariri and Ahmed Basabrain at the University of Massachusetts Amherst, MA, USA</p>
<ol class="note-items">
	<li data-note-item="1" data-parent-collapse="">Recrystallization of Acetanilide<button class="expand">Expand</button>
	<p>In this part of the lab, you&#39;ll purify acetanilide by recrystallization from an aqueous solution. Acetanilide is moderately soluble in boiling water, but it&#39;s much less soluble in room temperature and cold water. Aniline, a potential impurity, is much more soluble in room temperature water. Thus, you&#39;ll first make a saturated solution of acetanilide in boiling water. Then, you&#39;ll slowly cool the solution to room temperature.</p>
	<p>As the acetanilide&#39;s solubility decreases, it will slowly form flat colorless or white crystals. Water-soluble impurities will remain in solution. You will then cool the solution to further decrease the solubility of acetanilide. Finally, you&#39;ll recover the crystals with vacuum filtration and measure the melting point of your crystals.</p>
	<ul class="lab-items">
		<li data-sub-note-item="1-3">
		<div class="lab-step">Before you start the lab, put on a lab coat, safety glasses, and nitrile gloves.</div>
		</li>
		<li data-sub-note-item="1-4">
		<div class="lab-step">To begin, bring a 125-mL Erlenmeyer flask and your lab notebook to the analytical balance to obtain your acetanilide.</div>
		</li>
		<li data-sub-note-item="1-5">
		<div class="lab-step">Measure 2 g of acetanilide in a tared weighing boat and record the precise mass in your lab notebook. Add the acetanilide to the flask and bring it back to your fume hood.
		<h4><strong>Table 1: Recrystallization of acetanilide</strong></h4>
		<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
			<tbody>
				<tr>
					<td><strong>Compound</strong></td>
					<td><strong>Mass (g) </strong></td>
					<td><strong>Melting point (&#176;C) </strong></td>
				</tr>
				<tr>
					<td>Acetanilide</td>
					<td></td>
					<td></td>
				</tr>
				<tr>
					<td>Seed crystal (if used)</td>
					<td></td>
					<td></td>
				</tr>
				<tr>
					<td>Recrystallized acetanilide<br />
					(<em>subtract seed crystal if used</em>)</td>
					<td></td>
					<td></td>
				</tr>
				<tr>
					<td></td>
					<td></td>
					<td></td>
				</tr>
				<tr>
					<td><strong>Percent recovery</strong></td>
					<td></td>
					<td></td>
				</tr>
			</tbody>
		</table>
		<a href="https://www-jove-com.bdigitaluss.remotexs.co/CDNSource/lm/labs/58/Table_1._Recrystallization_of_acetanilide.xlsx" target="_blank">Click Here to download Table 1</a></div>
		</li>
		<li data-sub-note-item="1-6">
		<div class="lab-step">Then, measure 30 mL of deionized water and carefully pour it into the flask of acetanilide.</div>
		</li>
		<li data-sub-note-item="1-7">
		<div class="lab-step">Place the flask on a stirring hotplate, add a stir bar, and set the hotplate to medium heat and stirring. Let the mixture boil for 4 &#8211; 5 min to dissolve the acetanilide.</div>
		</li>
		<li data-sub-note-item="1-8">
		<div class="lab-step">If you see solid acetanilide after the solution has boiled for 5 min, measure another 10 mL of deionized water. Use a Pasteur pipette to add water dropwise until either the solid dissolves or you&#39;ve added all 10 mL.</div>
		</li>
		<li data-sub-note-item="1-9">
		<div class="lab-step">Let the solution boil for at least a minute after each milliliter before adding more water.<strong> Note:</strong> It&#39;s important to add water slowly so that you don&#39;t cool the solution too much or add more water than you need.</div>
		</li>
		<li data-sub-note-item="1-10">
		<div class="lab-step">If you still see some solid after that, those are impurities that you must remove by hot filtration. If you do not see solid, continue the lab at step 14.</div>
		</li>
		<li data-sub-note-item="1-11">
		<div class="lab-step">To perform hot filtration, place about 15 mL of deionized water and one or two boiling chips in a 50-mL beaker and start heating it on a hotplate.</div>
		</li>
		<li data-sub-note-item="1-12">
		<div class="lab-step">Clamp another 125-mL Erlenmeyer flask on a hotplate and place a wide stem or stemless glass funnel in the flask. Fold a large piece of circular filter paper in quarters, place it point down in the funnel, and open it into a cone.</div>
		</li>
		<li data-sub-note-item="1-13">
		<div class="lab-step">Once the water boils, use a pipette to wet the filter paper with hot water. Then, use tongs to pick up the flask of acetanilide solution and pour the hot liquid into the funnel, being careful not to let it overflow. <strong>Note:</strong> If the stir bar falls into the funnel, retrieve it with tweezers and rinse it with hot water.</div>
		</li>
		<li data-sub-note-item="1-14">
		<div class="lab-step">Then, rinse the inside of the first flask with a few milliliters of hot water, pour the contents into the funnel, and dissolve any crystals that form with hot water.</div>
		</li>
		<li data-sub-note-item="1-15">
		<div class="lab-step">Once the funnel is empty, use tongs to move it to the first flask. Carefully unclamp the second flask. You can now continue with the lab as usual.</div>
		</li>
		<li data-sub-note-item="1-16">
		<div class="lab-step">Once there is no visible solid in your hot acetanilide solution, turn off the heat and stir motor and use tongs to place the flask on the floor of the hood.</div>
		</li>
		<li data-sub-note-item="1-17">
		<div class="lab-step">Leave the solution undisturbed as it cools to room temperature, which usually takes at least 15 min. Moving or shaking the flask will make it harder for crystals to form.</div>
		</li>
		<li data-sub-note-item="1-18">
		<div class="lab-step">While you wait, place a small amount of the starting acetanilide material in a weighing boat and bring it to the melting point apparatus.</div>
		</li>
		<li data-sub-note-item="1-19">
		<div class="lab-step">Pack a capillary tube with the acetanilide and measure and record its melting point.</div>
		</li>
		<li data-sub-note-item="1-20">
		<div class="lab-step">Once the solution cools, look for crystals without moving the flask too much. If you don&#39;t see any, use a glass rod to gently scratch the inside of the flask under the solution. It&#39;s easier for crystals to start to form on scratched or rough surfaces.</div>
		</li>
		<li data-sub-note-item="1-21">
		<div class="lab-step">If crystals still haven&#39;t formed after 10 more min, ask your instructor for a seed crystal of high purity acetanilide. Measure and record the mass of the seed crystal, and then drop it into the room temperature acetanilide solution. Crystal growth will then occur on the seed crystal.</div>
		</li>
		<li data-sub-note-item="1-22">
		<div class="lab-step">Once you see several crystals in the flask, prepare two ice baths in 600-mL beakers. One ice bath should nearly fill the beaker, and the other should occupy about half of the beaker.</div>
		</li>
		<li data-sub-note-item="1-23">
		<div class="lab-step">Measure 5 mL of deionized water and place it in the full ice bath. Confirm that the flask is cool to the touch and that several crystals have formed before gently placing it in the half-full ice bath. Leave the flask undisturbed to improve crystal growth.</div>
		</li>
		<li data-sub-note-item="1-24">
		<div class="lab-step">Check the crystal growth progress every 15 min. Once it looks like most of your acetanilide has crystallized, or you don&#39;t see much crystal growth over a 15-min period, set up for a vacuum filtration using a 125- or 250-mL filter flask.</div>
		</li>
		<li data-sub-note-item="1-25">
		<div class="lab-step">Wet the filter paper with 1 mL of ice-cold water. Then, start the vacuum and pour the contents of the flask into the B&#252;chner funnel of the vacuum filtration setup.</div>
		</li>
		<li data-sub-note-item="1-26">
		<div class="lab-step">Scrape crystals from the flask into the funnel using a glass rod or flexible spatula and rinse the remaining crystals into the funnel with about 1 mL of cold deionized water.</div>
		</li>
		<li data-sub-note-item="1-27">
		<div class="lab-step">Then, stop the vacuum, break the seal, and pour the rest of the cold deionized water into the funnel. Gently stir the crystals with the glass rod for a few seconds to wash them, being careful not to tear the filter paper.</div>
		</li>
		<li data-sub-note-item="1-28">
		<div class="lab-step">Turn on the vacuum to drain the funnel. Then, stop the vacuum, break the seal, and empty the filtrate into a waste beaker. Turn the vacuum back on, and leave the washed crystals in the funnel while the vacuum pump pulls air through them until they are dry, which usually takes about half an hour. You&#39;ll start working on your next recrystallization while you wait.</div>
		</li>
	</ul>
	</li>
	<li data-note-item="2" data-parent-collapse="">Recrystallization of <em>trans</em>-Cinnamic Acid<button class="expand">Expand</button>
	<p>In the second half of the lab, you&#39;ll recrystallize <em>trans</em>-cinnamic acid, which we&#39;ll just call cinnamic acid. Cinnamic acid is soluble in ethanol and nearly insoluble in water. So, you&#39;ll use a mixture of 95% ethanol and 5% water so that cinnamic acid is still soluble at high temperatures but less soluble at low temperatures.</p>
	<ul class="lab-items">
		<li data-sub-note-item="2-2">
		<div class="lab-step">To get started, fill a 5- or 10-mL graduated cylinder with deionized water and bring it to your hood.</div>
		</li>
		<li data-sub-note-item="2-3">
		<div class="lab-step">Then, weigh 0.5 g of cinnamic acid, record its mass, and place it in a 25-mL Erlenmeyer flask.
		<h4><strong>Table 2: Recrystallization of<em> trans</em>-Cinnamic acid</strong></h4>
		<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
			<tbody>
				<tr>
					<td><strong>Compound</strong></td>
					<td><strong>Mass (g) </strong></td>
					<td><strong>Melting point (&#176;C) </strong></td>
				</tr>
				<tr>
					<td><em>trans</em>-Cinnamic acid</td>
					<td></td>
					<td></td>
				</tr>
				<tr>
					<td>Seed crystal (if used)</td>
					<td></td>
					<td></td>
				</tr>
				<tr>
					<td>Recrystallized<em> trans</em>-cinnamic acid<br />
					<em>(subtract seed crystal if used)</em></td>
					<td></td>
					<td></td>
				</tr>
				<tr>
					<td></td>
					<td></td>
					<td></td>
				</tr>
				<tr>
					<td><strong>Percent recovery</strong></td>
					<td></td>
					<td></td>
				</tr>
			</tbody>
		</table>
		<a href="https://www-jove-com.bdigitaluss.remotexs.co/CDNSource/lm/labs/58/Table_2._Recrystallization_of_trans-Cinnamic_acid.xlsx" target="_blank">Click Here to download Table 2</a></div>
		</li>
		<li data-sub-note-item="2-4">
		<div class="lab-step">Next, obtain 4 mL of 95% ethanol, and pour it into the flask containing cinnamic acid. Place the flask on a hotplate set to medium heat and stir the solution with a glass rod until the cinnamic acid dissolves, which usually takes 7 &#8211; 10 min.</div>
		</li>
		<li data-sub-note-item="2-5">
		<div class="lab-step">Then, turn off the heat and use a Pasteur pipette to add 5 drops of deionized water to the solution. This reduces cinnamic acid solubility. <strong>Note:</strong> If you don&#39;t see precipitation, add up to 5 more drops of water one by one. Stop adding water if you see solids starting to form.</div>
		</li>
		<li data-sub-note-item="2-6">
		<div class="lab-step">Then, remove the flask from the hotplate and let it cool to room temperature undisturbed.</div>
		</li>
		<li data-sub-note-item="2-7">
		<div class="lab-step">While you wait, get a small amount of the starting cinnamic acid and measure its melting point.</div>
		</li>
		<li data-sub-note-item="2-8">
		<div class="lab-step">Once the flask has cooled to room temperature, inspect it for crystals. If you don&#39;t see any, gently scratch the inside of the flask under the solution with the glass rod and wait for 10 min. <strong>Note:</strong> If that still doesn&#39;t work, get a seed crystal of cinnamic acid from your instructor. Remember to weigh the seed crystal and record its mass before you add it to your solution.</div>
		</li>
		<li data-sub-note-item="2-9">
		<div class="lab-step">Once the flask is cool to the touch and contains several crystals, remake the ice baths with one ice bath shallow enough that the 25-mL flask will not be completely submerged.</div>
		</li>
		<li data-sub-note-item="2-10">
		<div class="lab-step">Refill the graduated cylinder with deionized water. Place the flask of cinnamic acid crystals in the shallow ice bath and the water-filled graduated cylinder in the other ice bath. Let the crystals grow for at least 15 min.</div>
		</li>
		<li data-sub-note-item="2-11">
		<div class="lab-step">Your acetanilide crystals should be dry by now, so measure their mass and melting point while you wait for your cinnamic acid to finish crystallizing. Turn off the vacuum and break the vacuum seal.</div>
		</li>
		<li data-sub-note-item="2-12">
		<div class="lab-step">Gently place the B&#252;chner funnel in a clean beaker and bring it to the balance. Measure and record the mass of your pure acetanilide crystals. Remember to subtract the mass of the seed crystal if you used one.</div>
		</li>
		<li data-sub-note-item="2-13">
		<div class="lab-step">Then, bring your crystals to the melting point apparatus and measure and record the melting point.</div>
		</li>
		<li data-sub-note-item="2-14">
		<div class="lab-step">Now, place a clean, dry B&#252;chner funnel with a new piece of filter paper in the filter flask and check on your cinnamic acid. Once it looks like most of the cinnamic acid has crystallized, wet the filter paper with cold deionized water.</div>
		</li>
		<li data-sub-note-item="2-15">
		<div class="lab-step">Start the vacuum and pour the contents of the cinnamic acid flask into the funnel. Scrape the remaining crystals out of the flask with the glass rod and rinse the flask with about 1 mL of cold water.</div>
		</li>
		<li data-sub-note-item="2-16">
		<div class="lab-step">Now, turn off the vacuum, break the seal, and pour the rest of the cold water into the funnel. Gently stir the crystals with the glass rod to wash them, being careful not to damage the filter paper.</div>
		</li>
		<li data-sub-note-item="2-17">
		<div class="lab-step">Turn on the vacuum to drain the funnel. Leave the vacuum running until the cinnamic crystals are dry.</div>
		</li>
		<li data-sub-note-item="2-18">
		<div class="lab-step">Place the B&#252;chner funnel in a beaker and bring it to the balance. Measure and record the mass of your pure cinnamic acid crystals. Remember to subtract the mass of the seed crystal if you used one. Then, measure the melting point of your recrystallized cinnamic acid.</div>
		</li>
		<li data-sub-note-item="2-19">
		<div class="lab-step">Now, dispose of your acetanilide and cinnamic acid in the designated solid waste container. Flush the filtrate down the drain with running water and pour leftover ice and water into the sink.</div>
		</li>
		<li data-sub-note-item="2-20">
		<div class="lab-step">Clean your glassware using your usual methods and put away your other lab equipment.</div>
		</li>
		<li data-sub-note-item="2-21">
		<div class="lab-step">Lastly, discard your used pipettes in the glass waste and throw out used filter paper and other trash in the lab trash container.</div>
		</li>
	</ul>
	</li>
	<li data-note-item="3" data-parent-collapse="">Results<button class="expand">Expand</button>
	<ul class="lab-items">
		<li data-sub-note-item="3-1">
		<div class="lab-step">First, calculate the percent recovery for each compound. We expect that some of each compound stayed in solution, so these percentages will be below the reported purity of your starting material.</div>
		</li>
		<li data-sub-note-item="3-2">
		<div class="lab-step">Now, look at the differences in melting points between the starting material and the crystals. For each compound, the less pure starting material has a lower melting point and a broader range than the recrystallized compound.</div>
		</li>
		<li data-sub-note-item="3-3">
		<div class="lab-step">Lastly, compare your results to the literature values. The melting point of acetanilide is 114 &#176;C, and the melting point of <em>trans</em>-cinnamic acid is 133 &#176;C. The melting points of your crystals should span 1 &#8211; 2 &#176;C and should be at or just below those values.</div>
		</li>
	</ul>
	</li>
</ol>

Recrystallization of Acetanilide and trans-Cinnamic Acid - Procedure

재결정화

Source: Lara Al Hariri and Ahmed Basabrain at the University of Massachusetts Amherst, MA, USA

	Recrystallization of AcetanilideExpand
	In this part of ...

Simple Distillation

<p>Source: Lara Al Hariri and Ahmed Basabrain at the University of Massachusetts Amherst, MA, USA</p>
<ol class="note-items">
	<li data-note-item="1" data-parent-collapse="">Simple Distillation<button class="expand">Expand</button>
	<p>In this lab, you will use simple distillation to separate a mixture of cyclohexane and toluene.</p>
	<ul class="lab-items">
		<li data-sub-note-item="1-2">
		<div class="lab-step">Before you start the lab, put on the appropriate personal protective equipment, including a lab coat, safety goggles, and gloves. This experiment must be conducted in a hood.</div>
		</li>
		<li data-sub-note-item="1-3">
		<div class="lab-step">Assemble the distillation apparatus. Refer to the example set up that has been prepared by your instructor.</div>
		</li>
		<li data-sub-note-item="1-4">
		<div class="lab-step">Then, set up the two stands next to each other in the hood. Place the magnetic stirrer on the base of one of the stands.</div>
		</li>
		<li data-sub-note-item="1-5">
		<div class="lab-step">Set the heating mantle on top of the magnetic stirrer, and then plug it into the temperature controller.</div>
		</li>
		<li data-sub-note-item="1-6">
		<div class="lab-step">Add 5 &#8211; 10 mL of sand to the heating mantle. This will allow more homogeneous heating of the round-bottom flask. Clamp the round-bottom flask to the stand above the heating mantle.</div>
		</li>
		<li data-sub-note-item="1-7">
		<div class="lab-step">Now, obtain cyclohexane and toluene from your instructor. Measure 2 mL of cyclohexane using a volumetric pipette and dispense it into the round-bottom flask.</div>
		</li>
		<li data-sub-note-item="1-8">
		<div class="lab-step">Then, use a clean volumetric pipette to measure 2 mL of toluene and add it to the flask.</div>
		</li>
		<li data-sub-note-item="1-9">
		<div class="lab-step">Carefully insert a thermometer into an adapter by gently pushing and twisting it through the top.</div>
		</li>
		<li data-sub-note-item="1-10">
		<div class="lab-step">Lightly grease the adapter with vacuum grease and insert it into the distilling head. Make sure that the thermometer bulb is below the bend of the distilling head. Then, lightly grease the joints of the distilling head.</div>
		</li>
		<li data-sub-note-item="1-11">
		<div class="lab-step">Add a stir bar to the round-bottom flask and insert the distilling head into the round-bottom flask.</div>
		</li>
		<li data-sub-note-item="1-12">
		<div class="lab-step">Now, clamp the condenser to the second stand with it oriented diagonally toward the side joint of the distilling head.</div>
		</li>
		<li data-sub-note-item="1-13">
		<div class="lab-step">Connect one piece of tubing to the tap water faucet in the hood, and attach the other end to the inlet port of the condenser, which is located farthest from the distilling head.</div>
		</li>
		<li data-sub-note-item="1-14">
		<div class="lab-step">Attach the second tubing to the outlet port, which is located closest to the distilling head, and place the other end of the tubing into the drain.</div>
		</li>
		<li data-sub-note-item="1-15">
		<div class="lab-step">Connect the condenser to the distilling head. Then, lightly grease the joint of the condenser and attach the connecting tube. Place a 10-mL graduated cylinder below the outlet of the tube.</div>
		</li>
		<li data-sub-note-item="1-16">
		<div class="lab-step">Gently lower the setup until the round-bottom flask is seated in the sand in the heating mantle.</div>
		</li>
		<li data-sub-note-item="1-17">
		<div class="lab-step">Double-check all of the connections on your setup to make sure that they are tight and oriented correctly. Secure each joint with a plastic clip.</div>
		</li>
		<li data-sub-note-item="1-18">
		<div class="lab-step">Now, slowly turn on the flow of water to the condenser. <strong>Note:</strong> Be careful not to turn on the water too quickly. If the water pressure is high, the tubing may pop off the condenser.</div>
		</li>
		<li data-sub-note-item="1-19">
		<div class="lab-step">Turn the magnetic stirrer to the lowest setting, and set the temperature controller to heat the mantle to just above 90 &#176;C.</div>
		</li>
		<li data-sub-note-item="1-20">
		<div class="lab-step">Once bubbles start forming in the liquid mixture, adjust the heat until the distillation rate is about 2 drops/min. You should also see drops forming on the thermometer bulb.</div>
		</li>
		<li data-sub-note-item="1-21">
		<div class="lab-step">Record the temperature after every 2 drops that fall into the graduated cylinder or every minute.
		<h4><strong>Table 1: Distillation of toluene and cyclohexane</strong></h4>
		<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
			<tbody>
				<tr>
					<td><strong>Time (min) </strong></td>
					<td><strong>Distilled volume (mL) </strong></td>
					<td><strong>Temperature (&#176;C) </strong></td>
				</tr>
				<tr>
					<td style="text-align: center;">1</td>
					<td style="text-align: center;"></td>
					<td style="text-align: center;"></td>
				</tr>
				<tr>
					<td style="text-align: center;">2</td>
					<td style="text-align: center;"></td>
					<td style="text-align: center;"></td>
				</tr>
				<tr>
					<td style="text-align: center;">3</td>
					<td style="text-align: center;"></td>
					<td style="text-align: center;"></td>
				</tr>
				<tr>
					<td style="text-align: center;">4</td>
					<td style="text-align: center;"></td>
					<td style="text-align: center;"></td>
				</tr>
				<tr>
					<td style="text-align: center;">5</td>
					<td style="text-align: center;"></td>
					<td style="text-align: center;"></td>
				</tr>
				<tr>
					<td style="text-align: center;">6</td>
					<td style="text-align: center;"></td>
					<td style="text-align: center;"></td>
				</tr>
				<tr>
					<td style="text-align: center;">7</td>
					<td style="text-align: center;"></td>
					<td style="text-align: center;"></td>
				</tr>
				<tr>
					<td style="text-align: center;">8</td>
					<td style="text-align: center;"></td>
					<td style="text-align: center;"></td>
				</tr>
				<tr>
					<td style="text-align: center;">9</td>
					<td style="text-align: center;"></td>
					<td style="text-align: center;"></td>
				</tr>
				<tr>
					<td style="text-align: center;">10</td>
					<td style="text-align: center;"></td>
					<td style="text-align: center;"></td>
				</tr>
				<tr>
					<td style="text-align: center;">11</td>
					<td style="text-align: center;"></td>
					<td style="text-align: center;"></td>
				</tr>
				<tr>
					<td style="text-align: center;">12</td>
					<td style="text-align: center;"></td>
					<td style="text-align: center;"></td>
				</tr>
				<tr>
					<td style="text-align: center;">13</td>
					<td style="text-align: center;"></td>
					<td style="text-align: center;"></td>
				</tr>
				<tr>
					<td style="text-align: center;">14</td>
					<td style="text-align: center;"></td>
					<td style="text-align: center;"></td>
				</tr>
				<tr>
					<td style="text-align: center;">15</td>
					<td style="text-align: center;"></td>
					<td style="text-align: center;"></td>
				</tr>
			</tbody>
		</table>
		<a href="https://www-jove-com.bdigitaluss.remotexs.co/CDNSource/lm/labs/60/Table_1._Distillation_of_toluene_and_cyclohexane.xlsx" target="_blank">Click Here to download Table 1</a></div>
		</li>
		<li data-sub-note-item="1-22">
		<div class="lab-step">When there is about 0.5 mL of the mixture remaining in the flask, which will look like a thin layer of liquid, turn off the heat and gently lift the glassware setup from the heating mantle. <strong>Note:</strong> Never heat the mixture until the flask is dry as this may cause an explosion.</div>
		</li>
		<li data-sub-note-item="1-23">
		<div class="lab-step">Remove the stir plate with the heating mantle and set it aside.</div>
		</li>
		<li data-sub-note-item="1-24">
		<div class="lab-step">Then, turn off the water to the condenser and allow the setup to cool completely. When it is cool, carefully disassemble the glassware.</div>
		</li>
		<li data-sub-note-item="1-25">
		<div class="lab-step">Dispose of all solutions in the non-halogenated organic waste container. Clean your glassware with acetone followed by detergent and deionized water.</div>
		</li>
	</ul>
	</li>
	<li data-note-item="2" data-parent-collapse="">Results<button class="expand">Expand</button>
	<ul class="lab-items">
		<li data-sub-note-item="2-1">
		<div class="lab-step">Plot the dew point temperature versus the distilled volume during the experiment. We see that drops start to fall into the collection vessel at ~ 81 &#176;C, which is the boiling point of cyclohexane. As the distillation progresses, the temperature increases to almost 111 &#176;C, which is the boiling point of toluene.</div>
		</li>
		<li data-sub-note-item="2-2">
		<div class="lab-step">Early in the distillation, the vapor is rich in cyclohexane. As the second milliliter is distilled, the temperature increases by ~ 20 &#176;C, which tells us that the amount of toluene in the vapor is increasing significantly. The temperature stabilizes as it approaches 111 &#176;C, which tells us that the vapor is rich in toluene towards the end of the distillation.</div>
		</li>
		<li data-sub-note-item="2-3">
		<div class="lab-step">Look at a boiling point diagram for cyclohexane and toluene, with the mole percent of cyclohexane and toluene on the x-axis and the temperature on the y-axis. The solid line denotes the bubble point, and the dashed line denotes the dew point.</div>
		</li>
		<li data-sub-note-item="2-4">
		<div class="lab-step">Use the dew point curve to determine the composition of the vapor throughout the distillation. For example, after 0.5 mL has been distilled, the condensing vapor is about 84 &#176;C. This corresponds to 95% cyclohexane on the dew point curve.</div>
		</li>
		<li data-sub-note-item="2-5">
		<div class="lab-step">Once you know the composition of the vapor at each point, estimate the composition of the boiling mixture throughout the distillation. At room temperature, cyclohexane and toluene have nearly the same number of moles per milliliter, so think of the percentages in terms of volume.</div>
		</li>
		<li data-sub-note-item="2-6">
		<div class="lab-step">To determine how much of each liquid was distilled in each step, apply each percentage to the volume of liquid distilled since the previous measurement. This tells us that we distilled 1.9 mL of cyclohexane and 1.1 mL of toluene from our mixture of 2 mL of each liquid. Thus, our distillate was 63% cyclohexane and 37% toluene, and our remaining liquid mixture was 10% cyclohexane and 90% toluene.</div>
		</li>
	</ul>
	</li>
</ol>

Simple Distillation: Separation of a Mixture of Cyclohexane and Toluene - Procedure

간단한 증류

Source: Lara Al Hariri and Ahmed Basabrain at the University of Massachusetts Amherst, MA, USA

	Simple DistillationExpand
	In this lab, you will use ...