WSU-Summer 2012; Principles of Organic Chemistry II Laboratory; Chemistry 351 with Dr. Nalli

Guidelines for Lab Reports

Learning how to effectively report experimental results is extremely important in all of the sciences. Although the customary format may vary between discipline, a scientific report should be clear, concise,  and well organized and should make effective use of tables and graphs.

General Guidelines

  • The report should be thorough, well written, and well organized. 
  • Reports should be word-processed  and double-spaced.
  • Do not ignore the need for subscripts and superscripts in chemical formulas. These are easily available in all modern word processors.
  • Bonus points will be awarded to reports that use molecule drawing software to present professional-looking rather than hand-drawn reaction graphics.
  • Strive to present the results in as concise a manner as possible. A page limit of 12 pages (not counting attachments) applies to all lab reports. (Please number the pages!)

Title Page

  • Give the number and title of the experiment, your name, course number and section, and the date submitted.

Purpose

  • Give specific information on the reaction being carried out including chemical equations showing structures of all reactants and products.

Mechanism

  • Present the accepted mechanism for the reaction carried out. Make sure to use equations/structures/curved arrows as necessary to show the mechanism properly.

Results Tables

  • Present all of the results of the experiment in table form.
    • Try to make your results tables as concise and well organized as possible.
    • Number and title your tables. The title should give fairly complete information about the data contained in the table.
  • Include the absolute yield (mass) and percent yield of any product obtained.
  • A melting point range should be reported for every crystalline solid product.
  • Include literature values for any physical constants measured. 
  • Also include summaries (i.e., peak listings) of any spectroscopic data (NMR, IR, MS) obtained. Do not include solvent peaks in these listings. Do include literature values when available.
    • Important: Only those IR absorptions diagnostic for major functional groups, and only those MS peaks used for structure assignment, should be included in the experimental section. Round off IR frequencies to the nearest 1 cm-1 and MS peaks to the nearest 1 m/z unit. Carbon NMR peak shifts should be rounded off to the nearest 0.1 ppm except when greater precision is needed to distinguish closely spaced peaks. (These guidelines are taken verbatim from the Journal of Organic Chemistry's guidelines for authors.)
  • Make sure to give units where required. (A well-organized table gives the units in the column headings rather than repeatedly throughout the table.)
  • Make sure  to observe the significant figures convention!
  • Use footnotes as necessary to fill in missing details or to give definitions of abbreviations used in the table.
  • Also use footnotes to give references for literature values.

Results and Discussion 

  • Start by presenting key results from the results tables briefly in a non-interpretive way. Point out the most important take-home points from the table and/or any trends you would like to draw attention to.
  • Go on to explain your interpretation of these results. Your main aim is to show how they support the theories presented in the background.
  • Make liberal use of structural diagrams, equations, curved arrows, images of molecular models, etc., to illustrate points being made as appropriate.
  • For puzzling results that do not seem to fit the theoretical expectations, are there valid explanations for them? Are they erroneous (due to systematic experimental error) (identify the specific reason for the systematic error if you think it is present). If you can rule out systematic error then examine how the theories could be modified to accomodate the results.
  • This section should include answers to the asigned questions. Make sure to explain all answers completely even if the question does not ask for an explanation. 
  • Above all, make sure your answers and interpretations make sense! Do not just take a stab at interpreting the results! If uncertain, do some Internet and/or library research or ask the instructor if you are on the right track.
  • For synthesis experiments always discuss:
    • Yield - Actual yield of product versus the theoretical yield (percent yields) and possible reasons for loss of yield.
    • Spectra Interpretation - Evidence for the structure of the product from NMR, IR and/or chemical tests.
    • Purity - Purity of the product as indicated by mp, bp, NMR,  etc. Identify impurities that are present if possible, explaining thoroughly the reasoning behind your conclusions.

Summary

  • Reiterate the main points from your results and discussion sections in very brief form. Ideally, you can boil down the experiment to four or five main conclusions, each stated in one or two sentences.
  • Give actual data again in this section to support each conclusion. The data can be concisely included simply by providing it in parentheses at the appropriate places within the text..
  • Comment on whether the experiment was successful or not and feel free to make suggestions as to how the experiment could have been better designed or carried out.

References

  • Give sources for all literature values as well as for any other background information cited.

Attachments

  • Calculations - An example of each non-trivial calculation, including % and theoretical yield calculations, should be shown. Do not include trivial calculations such as subtraction of tare weights.

  • Spectra - Attach printouts of all spectra obtained. Make sure the spectra are completely labeled (name, date section number, expt number and title). All peaks should always be labeled. By labeling all solvent peaks and other expected extraneous peaks (e.g., TMS, water) you make clear what they are without unnecessarily devoting lab report discussion to them.

Product Submission

  • Products are ordinarily submitted for grading and then proper disposal. Submitted products should be fully labeled with the compound name and structure, your name, experiment number, and course number.
  • Solid products should be placed in small 2"x2" zip-lock baggies.
  • Liquid products should be placed in screw-top vials (not conical vials or reaction flasks).

Team Contribution Surveys (TCSs)

  • These are made available on D2L the same day the lab report is due for each experiment. They are due within one week of the lab report submission.