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Unformatted text preview: FALL 2009 Organic Chemistry 151L Laboratory GENERAL INFORMATION Organic Chemistry Laboratory Manager James A Parise, Ph.D. Office: French Family Science Center Room 1225 Phone: 660‐1615 Email: email@example.com Laboratory TA TA Email Course description Laboratory contributes 25% to a student’s overall Chem 151L grade. Credit for laboratory is only received once the lecture portion of the course has been completed. The purpose of the laboratory is to introduce students to common laboratory techniques, methods of separation and analysis, spectroscopy, and organic synthesis. It serves to prepare students for more advanced work in chemistry and related science and engineering fields. The course has been designed to compliment the lecture portion but not necessarily correspond topic‐by‐topic as the semester progresses. As such your laboratory procedures, literature references, and TA briefings will provide you with adequate background to conduct each experiment and write thoughtful post‐laboratory write‐ups. Supplies • Carbonless copy laboratory notebook ‐ available at the bookstore. • Goggles – available for $5 (cash or check made out to PLU) at the base of the large staircase in the FFSC for two weeks from Aug. 31st – Sep. 11th. They will be sold Tuesdays and Thursdays from 8:00 – 8:30AM, and Monday through Friday from 12:45 – 1:15PM. Standard and specialized goggles to be worn over glasses will be available. (Molecular Model Kits ($25) will also be sold at these times.) Goggles are also available in the bookstore. • Optional text: Fessenden, R.J., Fessenden, J.S., Feist, P. Organic Laboratory Techniques, 3rd ed.; Brooks/Cole: Pacific Grove, 2001. This text is also available on reserve at the Perkins Library. TA Name LAB POLICIES AND PROPER CONDUCT Appropriate Lab Attire Safety glasses are to be worn at all times in the laboratory. Additionally, shoes that cover the entire foot, shirts that cover the torso, chest and back with sleeves that reach at least to the elbow, and pants/shorts/skirts that reach at least to the knee are required. Within the criteria above, it is recommended that you not wear your favorite shirt, jeans or other article of clothing to lab. Even with careful lab practices, accidents do happen each semester and spilling corrosive chemicals on your clothes could ruin them. If you arrive without the proper attire, your TA will not allow you to participate in lab and you may receive a zero. Organic Chemistry 151L Laboratory Syllabus – Fall 2009 Revised 8/22/09 1 FALL 2009 Organic Chemistry 151L Laboratory Safety Your primary job, in association with your TA and lab mates, is to maintain a safe learning environment while in the laboratory. Your TA will review proper safety procedures in the event of a fire, chemical spill, chemical exposure, or other emergencies that may occur. Learn the location of the eyewash stations, safety shower, fire extinguishers, and both laboratory exit routes. Any accident, no matter how seemingly minor, should be reported to your TA. Food and drink are not permitted in lab. Academic Honesty The laboratory will be conducted according to the Duke Community Standard, and violations will be reported to the Office of Student Conduct. Reference information on academic integrity and the Duke Community Standard can be found at www.integrity.duke.edu. In this lab course students will be responsible for preparing, conducting, analyzing, and submitting their own experiments and work. ⇒ All work in the lab notebook must be completed by the individual and everything should be in the student’s own words. Each student should record his/her own data as the experiment progresses and must complete any analysis individually. ⇒ Students may discuss ideas and questions, but all written work (recording of data, observations, etc. in the lab notebook, and all work on individual reports, etc.) should be done individually, even when working in groups. While reports may contain similar raw data, everything should be presented in the student’s own words and formatting. ⇒ Honest discussion and collaborative data recording with other students or instructors, which is aimed at understanding and learning, is encouraged. However, copying another student’s data or work is a serious offense and will result in a grade of 0 and may be turned over to the Office of Student Conduct. Tardiness You are expected to attend every lab in your assigned section, to arrive on time, and should count on each lab taking the entire time period. If you arrive so late that you will not be able to contribute sufficiently, the TA will send you home. It is then your responsibility to make up the lab at a later time. Points will be deducted from your preparedness grade (see below) for tardiness. Lab Makeup Policy If you must miss your regularly scheduled lab period it is your responsibility to make it up. The experimental week starts on a Monday and ends on a Friday. You MUST make up the lab during the same experimental week that the experiment was missed. If you delay scheduling a make‐up and are therefore unable to make up the lab you will receive a zero for the lab. Follow these steps to make up a lab: 1) Choose a day and time that you are able to make up the lab. The following times are available: Monday – Friday: 1:15 – 4:15 pm Tuesday or Thursday: 8:30 – 11:30 am 2) Check the Room Schedule on the laboratory Blackboard site under Course Documents – Missed Experiment Information. If possible, find a section that meets in the lab room that you normally attend. 3) Download and fill out the “Lab Make‐up Form” available in the same folder on Blackboard. 4) Report to the lab room, introduce yourself to the TA and ask that they sign your make up form. Organic Chemistry 151L Laboratory Syllabus – Fall 2009 Revised 8/22/09 2 FALL 2009 Organic Chemistry 151L Laboratory 5) Take the quiz and ask the TA to grade and return it to you before you leave the lab. 6) After you have completed lab staple the graded quiz and your lab notebook pages from the previous experiment to your lab make‐up form and bring to Dr. Parise in 1225. Slide it under the door if no one is there. 7) One week after you made up the lab turn in all associated assignments to either your TA or Dr. Parise in 1225. You must include your section number and the name of your TA to receive credit. If the assignment is turned in late, penalties will apply. If you miss an experiment and are not able to schedule a makeup because of scheduling conflicts: If you are unable to make up one or two experiments: obtain a “Lab Excuse Form” available under Course Documents – Missed Experiment Info folder. Fill out the form and be sure to include the specific conflict that prevented make‐up of the missed lab. Staple your class schedule to the make‐up form and turn it in to the lab manager in room 1225. If the experiment was missed because of a legitimate reason (school related field trip, short‐term illness, family emergency, etc) the lab will be excused and the points associated with the experiment will be omitted from the total possible points. You do not need to fill out a ShortTerm Illness Form for an absence from lab. If you are unable to make‐up a third experiment (for example, if the reason for your absence was a long‐term illness or extraordinary personal reasons) you must obtain a Dean’s letter and present it to the lab manager as soon as possible to receive an excused absence. If you are unable to make‐up four or more experiments a grade of incomplete may be assigned. In this situation please contact Dr. Parise as soon as possible. If you fail to make up an unexcused absence, you will receive a grade of zero for that lab. Resources Teaching Assistant: Your TA is your primary resource for questions regarding lab, notebook keeping, etc. They will provide you with contact information. This syllabus: This document contains most of the course reference information you need regarding safety, lab makeups, notebook keeping, etc. Refer to it frequently; it has been prepared with the student’s needs in mind. Lab director: Dr. Parise is available to address concerns regarding your teaching assistant, group members, or answer questions about lab after you have consulted your TA. If you withdraw from Chem 151L late in the academic term, please contact Dr. Parise regarding possible completion of the laboratory. Peer tutoring: available as a free resource through the Peer Tutoring Office (684‐8832) Private tutoring: for a fee service offered by graduate students in the Chemistry Department: www.chem.duke.edu/undergraduates/tutors.php Academic Skills Instructional Program (ASIP): provides additional help developing appropriate study habits, time management or exam taking strategies: web.duke.edu/arc/academic_skills/index.php Organic Chemistry 151L Laboratory Syllabus – Fall 2009 Revised 8/22/09 3 FALL 2009 Organic Chemistry 151L Laboratory ASSIGNMENTS AND GRADING
Following is a description of the items that will contribute to your lab grade. Pre‐laboratory quiz (6 points each) – to cover the experiment performed the previous week and the experiment to be performed that day. Could include questions on safety, reactions, mechanisms, techniques, pre‐lab reading, spectroscopy, calculations such as limiting reagent and percent yield, etc. There will be no Pre‐Lab quiz the first lab meeting. Pre‐lab, Lab notebook pages, Post‐Lab Report (16 points/experiment) – for specific information see the Lab Reporting section of this syllabus. In‐lab performance (15 points/semester) – based on your overall performance in lab. How efficiently did you work? Did you leave your hood and glassware clean and organized? Did you handle the waste correctly? Were you wearing your goggles at all times during the experiment (1 point will be deducted each time you are found in lab without your goggles protecting your eyes)? Were your observations written directly into your notebook as you performed the experiment? Did you treat the equipment and instruments with care? Did you practice safe laboratory techniques? Preparedness (15 points/semester) – earn full credit if you arrive to lab ON TIME, prepared with your goggles and appropriate lab attire, and as a result of sufficient preparation conduct yourself in an organized and efficient manner. Balance Czar (3 points/semester) – maintain the cleanliness of the balance and balance area for one experiment. Cleanliness Czar (3 points/semester) – clean up glassware, chemicals, and equipment left out at the end of one experiment. Organize and wipe down common benches and chemical hood. May include maintaining the rotary evaporators: gather ice for cooling water and collection flasks, empty collection flasks at the end of the day, rinse traps and adaptors. Turn in notebook pages, post‐lab report, typed discussion, and spectra to your TA one week after an experiment has been performed. Deliver the assignment to your TA or the lab manager. Do NOT turn in any assignments to the Chemistry Department Office on the 3rd floor of FFSC. Late assignments will be penalized 1 point per day past the due date. Assignments will not be accepted beyond three weeks of the original due date, or the “last day to turn in assignments” (see below), whichever comes first. Check the gradebook on your lab section’s Blackboard site regularly to make sure that you have turned in all of the assignments and that the points have been entered correctly. It is your responsibility to report discrepancies to your TA as soon as they are recognized and before the “last day to report mistakes” (see below). Important dates Last day to turn in assignments for the semester: Monday, November 30. Last day to report mistakes in the online gradebook: Friday, December 4. Lab Equipment You and a lab partner will be assigned a set of glassware on the first day of laboratory. Points will be deducted from your performance grade if glassware is left dirty or is missing. Therefore, it is to your benefit to do a careful job inspecting the equipment at check‐in and cleaning up your area at the end of each lab. Organic Chemistry 151L Laboratory Syllabus – Fall 2009 Revised 8/22/09 4 FALL 2009 Organic Chemistry 151L Laboratory LAB REPORTING
Accurate record keeping is essential to many fields including chemistry. Doctors are required to take accurate, meticulous notes when speaking with patients to guarantee proper medical care; an accountant must keep a carefully detailed record of each transaction to avoid hassle with the IRS; a lawyer’s notes must be thorough and complete to avoid misinformation being presented at a trial. Likewise, the lab notebook is a permanent record of a chemist’s laboratory activities. Chemists often refer to their notebooks when applying for patents and writing scientific papers, and when formulating conclusions before moving forward with a research project. Additionally, the lab notebook is used as evidence when a company is taken to court. Because of these significant implications it is important to learn data collection techniques that prepare you for your future, regardless of your specific field of study. In chemistry 151 and 152 careful record keeping will be encouraged and enforced. Lab Reporting General Guidelines The goal when writing in your laboratory notebook should be to write clear enough and with sufficient organization and detail such that someone unfamiliar with the subject would be able to repeat your experiment exactly, using only your notebook. The following general guidelines should be followed: Write directly into your notebook – NOT on a separate sheet of paper. Inevitably, the paper will be lost or misplaced. To encourage formation of good habits your TA will sign your notebook pages before you leave lab each day. All procedural information and observations must be recorded at this time. Write in pen only, NOT pencil. Do not erase or use whiteout. Make corrections by drawing a single line through the mistake. Write neatly and leave a lot white space! If someone is to repeat your work they have to be able to read it and follow your organization. Permanently attach any graphs that are generated to the notebook with staples or tape. Your graded labs will consist of three parts: (1) a PreLab, (2) your in lab Notebook Pages, and (3) the PostLab Report. 1. Prelab Work It is essential that you come to lab prepared. This will help you better understand the chemistry, run the experiments more efficiently (spend less time in lab) and score better on the quiz. Before each lab you should: 1. Read the experiment posted in the laboratory Blackboard website. (2009 Fall) ORGANIC CHEM 151 Lab (All Sections) 2. Familiarize yourself with the equipment, glassware, and techniques that will be utilized in the experiment by referring to the assigned pages in Fessenden and Fessenden available on reserve at the Perkins library circulation desk. 3. Check the lab Blackboard site for important announcements and updates or corrections to the experiment. 4. Complete the required preliminary information in your lab notebook (see below: Pre‐lab Notebook Guidelines). Prelab Notebook Guidelines The following items must be in the notebook before coming to lab: Table of Contents Entry. – Enter the title and page number of each experiment in the table of contents. Organic Chemistry 151L Laboratory Syllabus – Fall 2009 Revised 8/22/09 5 FALL 2009 Organic Chemistry 151L Laboratory
Name, course and section number, title, and date – A full title should go on the first page of the experiment and an abbreviated title on the top of every page thereafter. Your name and the date must appear on every page. Objective ‐ The purpose for running the experiment. DO NOT copy directly from the manual. These are good guidelines, but you should write in your own words the reason(s) for conducting the experiment and what you hope to learn. Include the reaction (show structures!) and mechanisms (if known) for synthetic experiments. Table of Reagents and Products – A table of reagents used and product(s) synthesized in this experiment and the relevant physical constants. The relevant information will vary depending on the exact experiment. The chemicals used in the “work‐up” need not be listed. For example, most synthetic procedures require washing with a saturated brine solution, drying with Na2SO4, etc. When a technique is central to an experiment include the chemicals being isolated or analyzed. Be sure to reference values found in the literature. For example, CRC Handbook of Chemistry and Physics; Weast, R.C., Ed.; CRC Press: Boca Raton, Florida, 1978. Separation Scheme – a flowchart detailing how you will purify/isolate the product of interest. See Appendix 1 for a few examples of separation schemes. Reference Procedure ‐ Since the procedure is usually given in detail in the lab handouts the procedural details can be referenced. For example: See Chem 151L Laboratory Handout – Experiment Name for a detailed procedure. The pre‐lab work will be graded for organization, legibility, effort, and completeness not accuracy. 2. In lab Notebook Guidelines These items will be written in the notebook during lab: Observations – What did you see, feel, hear, etc? The following should be included: ⇒ Include any and all changes or additions you made to the procedure described in the handout. ⇒ Exact measurements and data – exact reagent amounts used and exact concentrations of reagents should be included in the Table of Reagents and Products above. ⇒ Problems encountered. ⇒ Physical data such as color, temperature, pressure, etc. ⇒ Amount of time required for addition of reagent or reflux, etc. ⇒ Observations must be written directly in the notebook as you are conducting the experiment, not after the lab is complete. Failure to comply will result in a loss of all points associated with the observations. 3. PostLab Report Guidelines These items will be written in the POST‐LAB REPORT during or after lab. You may choose to work through some of the items below first in your notebook then transfer some or all of the information to the post‐lab report. However, you are only required to include information through the observations section in your notebook. Mechanism and separation scheme – graded for accuracy on the post‐lab report. Based on what you learn during your TA’s pre‐lab discussion, performing the experiment, asking questions, Organic Chemistry 151L Laboratory Syllabus – Fall 2009 Revised 8/22/09 6 FALL 2009 Organic Chemistry 151L Laboratory
reading Loudon, etc., revise your original mechanism and separation scheme (if necessary) for the post‐lab report. Calculations – Use of dimensional analysis and units are required. Pay attention to significant figures. See Appendix 2 for details on the calculations that will most commonly be encountered. Results – the report will have places for you to include important results and to tabulate spectral information. Spectroscopy – include a copy of all spectra that you are asked to analyze. Indicate peak assignments directly on the spectra. Discussion – typed, 12‐point font, double spaced, 2 page limit. This section allows the TA to see if you understood the important concepts of the experiment. Think about the results obtained and attempt to analyze them. Include the following: ⇒ Summarize briefly your findings. Use your results as evidence to tell a story that culminates in your major conclusions. Be sure to evaluate your confidence in the results. Important note: any organic chemist can tell you that following a written, published procedure is no guarantee that you will actually get the product you set out to make. Therefore, treat all products isolated or synthesized as unknowns. Prove to the reader the true identity of the product(s). ⇒ Do your data agree with the accepted (literature) values? Always be sure to include the literature value and reference the source. Note: even though you have tabulated this information in the Table of Results it is still appropriate to rewrite it here and discuss its relevance. ⇒ Include a spectral analysis. Identify absorbances, resonances, fragmentations, etc. that give specific information about the structure of the product (and that suggest whether or not you have re‐isolated the starting material). For example, if you attempted to oxidize an alcohol to a ketone it would be important to point out that the alcohol peak at 3300 cm‐1 present in the staring material disappeared from the IR spectra and a carbonyl stretch at 1710 cm‐1 was now present. ⇒ What were the sources of error? Be specific ‐ do NOT state “human error”. Try to concentrate on errors specific to the experiment – for example by‐product formation, moisture sensitive starting materials, solubility problems, etc. This can be brief – a sentence or two. ⇒ What would you do differently if you were to repeat the experiment? Are there any additional experiments that could have made the results more clear? Organic Chemistry 151L Laboratory Syllabus – Fall 2009 Revised 8/22/09 7 FALL 2009 Organic Chemistry 151L Laboratory APPENDIX 1. SEPARATION SCHEMES
Generic Example of a Separation Scheme Mixture at end of a reaction (e.g. product + byproducts + unreacted starting materials +solvent + other impurities) or beginning of isolation experiment (all ingredients in a tablet of ibuprofen) An OPERATION that results in some kind of separation. Examples: extraction (aqeous/organic layers) filtration (solid/filrate), distillation (forerun and main fraction), etc. Product + some impurities (make sure you specify what the impurities are!) Another operation resulting in further purification. Some of the impurities (again, specify) Pure product impurities (specify) A separation scheme may have only one "Y" (e.g. a single distillation) or several "Y's" e.g. a basic wash followed by a neutral wash followed by a distillation. It is essential that you know why each operation is performed and what impurities are removed. Organic Chemistry 151L Laboratory Syllabus – Fall 2009 Revised 8/22/09 8 FALL 2009 Organic Chemistry 151L Laboratory Appendix 2. Common calculations required in organic chemistry In a synthesis experiment (one in which your goal is to prepare a pure compound from a set of reagents), you will always calculate a percent yield. This number reflects how much product you actually obtained (actual yield) compared to how much product is possible assuming the reaction went to 100% completion (theoretical yield). The actual and percent yields can be expressed as a measurement of mass (g), volume (mL), or moles (mol) – as long as they are the same (so that the units cancel and the result is a percentage – this is a good reminder to always keep track of your units!) percent yield = actual yield × 100% theoretical yield € Calculating theoretical yield. The theoretical yield is based on the stoichiometry of the reaction and therefore having a balanced chemical equation is essential. Let’s look at an example. Consider the reaction acetic acid with 3‐methyl‐1‐butanol to form isopentyl acetate (shown below): O H3C OH CH3 H3C CH CH2 CH2 OH 3-methyl-1-butanol 88.15 10.0 g O H+ H3C CH3 O CH2 CH2 CH CH3 acetic acid MW (g/mol) 60.05 isopentyl acetate 130.19 8.6 g One mole of acetic acid reacts with one mole of 3‐methyl‐1‐butanol to form one mole of isopentyl acetate. Therefore the stoichiometry is 1:1:1 (this is, of course, the simplest case). The next step is to determine which of the reagents is the limiting reagent. The limiting reagent is present in the least molar amount and therefore limits the amount of product that can be formed. A tasty example follows: let’s say we want to make s’mores. A s’more is made of one graham cracker, one chocolate square, and one marshmallow. If we have 12 graham crackers, 10 chocolate squares and 15 marshmallows the number of s’mores we can make is 10 – limited by the number of chocolate squares, the limiting reagent. Back to chemistry… Notice carefully that we have to compare MOLES of reagents, not grams, not milliliters, only moles in order to determine which is limiting. Therefore we have to convert the amounts used/obtained in our table above from grams and milliliters to moles. Amount used/obtained 8.0 mL Organic Chemistry 151L Laboratory Syllabus – Fall 2009 Revised 8/22/09 9 ...
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