WSU-Fall 2012; Principles of Organic Chemistry I Laboratory; Chemistry 350 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 concise but 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.
  • Strive to present the results in as concise a manner as possible. A page limit of 10 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.

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), theoretical yield, 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 non-standard 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.
  • 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.
  • 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.

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). Label all peaks on the NMR spectra. 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. For IR and Mass spectra it is not necessary to label small unidentifiable peaks especially those in the fingerprint region of the IR.

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.