How to Write a Lab Report for College Chemistry Courses
Many students believe that the requirements for a laboratory report change as the content changes or as their science courses become more difficult. In fact, the requirements for a lab report are the same for organic and physical chemistry as they are for genchem and even research in the professional field. Being able to write a coherent and well organized laboratory report is one of the most important skills to learn in college chemistry. Click here for a chemistry lab report template.
Here are the requirements for the chemistry lab report:
(On the Title Page)
(Title) Example: DETERMINATION OF THE CONCENTRATION OF QUININE IN TONIC WATER BY FLUORESCENCE SPECTROSCOPY
Your Name and Partner's Name Example: John Argon (Partner: Jane Antimony)
Course: Example: Instrumentation Laboratory, ChemGeeks University
Date of Experiment: May 13, 2017
A line or two about the method and theory, (very brief) leading up to the objective of the experiment. Example: Flourescence spectroscopy is based on the principle that... Because of this principle it is possible to quantitatively measure the concentration of quinine in a sample of tonic water. A couple lines on how your solutions were prepared or the experiment was set up (very, very brief!) In this experiment standard solutions of 1, 0.01, 0.001 and 0.0001ug/mL... were prepared by serial dilution in deionized water and the fluorescence spectra were obtained in a 1cm quartz cell... A line about how results were obtained and list numerical results. Absorbance was plotted against the concentration.Using the standard addition plot, the concentration of quinine in tonic water was determined to be...mg/mL (include error in measurement). Give two to three sources of error in the experiment. The sources of error in this experiment were preparation of sample and standards, instrumental noise...
(end of title page)
I. Introduction (most instructors want your sections to be numbered)
This section isn't always required for some courses. Classes that involve a substantial amount of theory or instrumental principle or complex reactions probably require one. First, state the purpose. The purpose of this experiment is to measure the concentration of quinine in a sample of tonic water...Discuss the principles of an instrument you use, state any equations used to obtain results, chemical reactions, and a schematic drawing if the apparatus is complex. The variables in equations should be identified and briefly described. References are often presented when using equations or if the procedure has been done before in a scientific journal (PChem!). The total length of the introduction varies with the complexity of an experiment, for most college courses it's between 100 and 300 words. Keep a focus on the goal of the experiment and what a reader has to know to understand how the experiment works in principle.
(The experimental section can be subdivided into subsections: Materials and Procedure.) If you are a student, it depends on the preference of your instructor.
Materials: List the apparatus components, (eg. pH meter, 50 mL buret, etc.) chemical used (note purity, grade and brand name for advanced coursework like instrumental lab or quantitative chemistry), describe your preparation of standard solutions.
Procedure: If you used a literature source for the procedure of the experiment, cite it here in the first sentence. The experimental method was similar to that described in the text (Christensen, 12th ed., Experiment 4) and describe in detail any deviations from that procedure. Otherwise simply tell the reader everything you did IN PAST TENSE. Six clean 50 mL volumetric flasks were obtained and filled to the line with...A total of five trials were performed...The solution was boiled...etc.
Before writing this section, make sure that all of your raw data has been processed and you have performed any necessary calculations, and prepared your graphs and tables. This is the most important part of the lab report: present all experimental results in detail without showing any excessive raw spreadsheet data or instrumental output. Display your tables and graphs with a descriptive title and a numbered caption (an example is shown below). Include error bars for the points on your graphs. For a linear graph, include the equation and R^2 value and remember to include least-square results. Remember to include the errors for numerical results with the proper significant figures.
Literature Sources for Laboratory Reports and Research - Spectral databases, molecular weights, m.p.'s, b.p.'s, chemical purities, organic structures.
How to Cite Sources in Chemistry - Applicable for both high school and university laboratory reports and research projects
American Chemical Society - Profession organization for those in the field of chemistry, access to research journal through your institution or a membership.
International Union of Pure and Applied Chemistry - Official chemistry organization that determines legitimacy of compound naming
Chemical and Engineering News - Magazine by the American Chemical Society for articles on the latest advances in chemistry and chemical engineering
Sigma-Aldrich Chemical Company - Chemical information, and common laboratory equipment and substances
Revisit the purpose of the experiment, discuss the main points, state the final numerical results with their respective errors and their sources. Are the errors systematic or random? Try to give specific effects of each source of error and how it can be eliminated to give more accurate results. Compare your results with those found in literature sources and databases, do they agree? If they don't, present possible reasons. Finally, state any difficulties in the experiment and propose ways that the experiment can be improved.
Sample Calculations: Put an example of all calculations you performed to get your final results here, including the propagation of errors. It is acceptable to hand-write these for most college and high school AP courses.
All the Resources You Need to Write a Laboratory Report
Figure 1: Near IR spectrum for standard CH2Cl2
A Periodic Table - links to interactive and printable periodic tables along with explanations of periodic trends