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.
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