The Laboratory Report - Organic Chemistry Laboratory | CHE 276, Lab Reports of Organic Chemistry

Download The Laboratory Report - Organic Chemistry Laboratory | CHE 276 and more Lab Reports Organic Chemistry in PDF only on Docsity! Totah rev. 8/2009 The Laboratory Report I. Format: Reports must be typed (double spaced) and must follow the format outlined below. Schemes and Figures may be handwritten, but should be neat and legible. The typical report will be from 3-4 pages long. It should be complete, but concise. Pages in excess of 5 (including tables, but excluding the Title Page and Appendices) will not be graded. Avoid excessive experimental procedure and theoretical discussion - you will lose points. To receive full credit, use proper format and follow the instructions carefully. II. Parts of the Report: A. Title Page: 1. Title 2. Experiment # 3. Identifying information (at lower right): Your name, Section #, TA, date submitted. B. Purpose: Discuss the general purpose of the experiment in two or three sentences (e.g. to investigate and compare various methods of distillation). This should be more than a simple restatement of the title. What will you learn? If you are performing a synthesis, include the balanced chemical equation. Note that the chemical equation provided in the text or handout may not be balanced! C. Results and Discussion: This is probably the most important section of the report. It is here that you will interpret your experimental data, and reach conclusions as to what that data implies. You will need to explain how you drew these conclusions clearly and logically. Be succinct. It usually works best to divide this section into multiple parts which correspond to the individual components of the experiment. For example, one synthetic step). In a sentence or two, tell what you did (e.g. reacted A with B to give C), then tell what you found. Do not include a detailed experimental account - you have already done so in your notebook. Do not include calculations. Instead, concentrate on your results. Give all the evidence you have that a particular technique or step was successful (or was not!). You will not always be told every piece of evidence that you should look for, but you should always include the following: 1. Amount of product (in grams) 2. Percent yield (indicate the limiting reagent) or recovery 3. Physical properties (color, state, etc.) 4. mp or bp (always report a range) 5. Literature value of mp/bp 6. TLC (report the Rf value and the solvent system used). Do NOT draw the plate. 7. GC (report the retention time, the # of other peaks present, and/or the % purity) 8. IR (report absorbance in cm-1; explain their significance. Identify the functional group each absorbance represents. Note absent absorbances as appropriate. Do not over interpret. Totah rev. 8/2009 Summarize your results in table format. You should include any graphs, structures, etc. that are necessary for your discussion. Do NOT include calculations. Tabulated values should be repeated in the text as appropriate for clarification. Draw specific conclusions. Did you make the compound or not? Did the distillation work or not? Is your product pure? What is the identity of your unknown? Do your results agree with your expectations? Why or why not? Be specific. Any conclusion you make must be supported with experimental evidence, either from the literature (cite references) or from your own studies. Be sure to clearly explain how you drew your conclusions. This might include a direct comparison of your theoretical expectations with the actual results you got, or a comparison of the physical and spectral properties of your product with those of the starting material. When possible, the experimental data you obtain should be compared with literature values. You can often find these values in the CRC handbook or Merck Index in the library. Discuss the yield of the product you obtained. Is it unreasonably low? Too high? Suggest possible explanations. D. Conclusions: Summarize the conclusions you reached in the Results and Discussion section. Was your experiment successful? Where appropriate, apply these conclusions to more generalized areas. For example, discuss what your specific result tells you about a general theory or class of reactions. Does your result agree with your expectation? Disagree? If a new technique was utilized, comment on it's effectiveness relative to what you were trying to accomplish. E. Appendices: You may not always have material for each appendix, but the material you do have must be labeled and appear in the following order: 1. Appendix A: Calculations For experiments which do not involve a synthetic transformation: a. Include one sample of each calculation that you do (Rf values, etc.). In each case, include the equation that you used, complete with units. For synthetic experiments: a. For each synthetic transformation, make a Table of Reagents which lists the amounts of reactants/reagents that you actually used in the reaction (in mL or grams). Convert these measurements into moles, and then into equivalents based on the limiting reagent (Note: a catalyst is never the limiting reagent). Identify the limiting reagent for each step. b. Include a complete percent yield calculation for each synthetic step of the experiment, as well as for the overall yield. Use the format specified. In each case, include the equation you used, complete with units. 2. Appendix B: Spectra (gc trace, IR, NMR, etc.) 3. Appendix C: Answers to assigned questions Will include both pre-lab (attached by TA) or post-lab questions (if any)