Lab Reports

You are required to use a laboratory notebook which produces a copy of your work. Generally, students buy the carbonless laboratory notebooks (50 or 100 page) sold in the Colorado bookstores. Please, write your name on the book! It's easier for a notebook to find its way home if your name is on it. (This goes for calculators, too, by the way.)

When you write your lab report, you need to calculate the amount of reagent used and the theoretical yield. For help, go to the Theoretical Yield page.

In version 1, the procedure is written out, followed by the data and observations. In version 2, the procedure and the data and observations are presented in a two-column table, so that an observation can be placed directly to the right of the corresponding step in the procedure.

The following components should be contained for each experiment, along with any additional material required by your instructor.

The Prelab includes components in yellow: title, introduction, physical data, procedure.The Prelab must be completed before you come to the laboratory period for which an experiment is scheduled.

The Write-up includes components in purple: data and observations and discussion.. A copy of your Write-up will be collected at the end of the laboratory period or the next day, as directed by your TA.

Prelab

Title and Date
Give the title of the experiment and the date on which it is done.
Introduction
In a sentence or two, state the purpose of the experiment. If the experiment is a preparative experiment, the introduction also includes the balanced equation for the reaction.

In organic chem 1, there are different types of experiments: technique and preparative. A technique experiment is one in which you are performing a technique for the first time and studying its details, for example, distillation and extraction. A preparative experiment is one in which a compound is synthesized from other reagents.
Physical Data
List the MW, melting point, boiling point, density, solubility, and hazards of all pertinent chemicals used in the experiment. For your convenience, tables of physical data for all chemicals used in this course are included in the Handbook for Organic Chemistry Lab. Or, you can find the information on the Internet (see: Hazard and Physical Data for Compounds page).

Calculate the amounts of reactants (or compounds to be purified) in moles and grams or mL (as applicable). In a preparative experiment, calculate the limiting reagent and the theoretical yield of the product. Be sure to include your calculations for these values. Refer to the Handbook for information on how to calculate yields. The physical data are most conveniently presented in tabular form, although in a preparative experiment you may put the amounts of reactants and products under the balanced equations for the reaction.
Procedure
Briefly summarize the procedure to be followed, preferably either as an outline or as a flow chart. You do not need to write out the procedure in complete sentences and do not copy directly from the Lab Manual. All you need is a brief but complete listing of what you plan to do in the lab. The first time you do a technique, such as distillation, include in the procedure section a description of how to assemble the apparatus and how to conduct the distillation. In later experiments, it will be sufficient to state only that the liquid was distilled.

Data and Observations

Your observations of the experiment as it progresses is important, new information. Write these observations (color changes, appearance of crystals, formation of an emulsion, boiling temperatures, test results, etc.) in your notebook as you do the experiment. Also record the weights of reagents and products and tare weights in this section.

In general, you do not need to re-write the Procedure section in these observations, instead, you may state that “the procedure was carried out as planned” or “the procedure was carried out as planned except . . . .” At times, however, you may have to write the procedure out partially. For instance, if you state “the solution turned green,” you will have to write out enough of the procedure so that your TA will know at what step in the reaction the solution turned green. As a guideline, consider that from the procedure and data and observations sections, any chemist should be able to duplicate your experiment. With this in mind, be thorough but include only pertinent information.

Discussion of Results

This is the section in which you interpret the data obtained in the previous section. For instance, indicate the amount of purified compound that you obtained and how the purity and identity of the compound was assessed. In a preparative experiment, state the percent yield. Include and discuss instrument printouts, such as GC traces and IR spectra. In this section, you can state whether or not the procedure was a good method for making the desired compound; if not, try to make suggestions to improve the method for future experimenters.

The Organic Chemistry Laboratory Notebook