There will be one individual effort formal report required of every General Chemistry student in each semester. Students should review the detailed instructions for writing a formal report, as well as the formal report writing guide in their lab manual. These instructions should be referred to when working on all formal report writing exercises.
Other materials that a student may find helpful:
FORMAL LAB REPORT, General
A formal lab report is required in conjunction with some of the experiments in each chemistry course. It is your chance to demonstrate to your professor or TA how well you understand the experiment and the chemical principles involved. A formal report is different than a term paper. It should be written in a scientific style, which is not the same style used for English or philosophy papers.
The keys to effective technical writing are organization, brevity, clarity, and an appreciation of the needs of the reader. You must write clearly and be thorough, but concise. Do not ramble. The best way to avoid rambling is to first prepare an outline of the report and stick to it. Always use complete sentences. Bulleted lists are okay in a lab notebook but are unacceptable in a formal report. Formal reports must be typed. Use 1.5 line spacing, 1-inch margins, 12 pt font and 8.5x11 inch paper. Only use third person, past tense. Also, proofread well.
The general structure of a formal lab report follows that of a scientific paper. It is: Title and Author (s)
Experimental Information and Data
Results and Discussion
Results and discussion sections are combined into one single section. Different instructors may have specific formats that they want you to follow. You should always defer to the instructions given to you by your course. Presented here are general guidelines for writing formal lab reports and scientific papers.
Before writing your first report, visit the library and examine several journal articles. Pay close attention to the style of the prose and the contents of each particular section. Several common journals to investigate are:
The Journal of the American Chemical Society
The Journal of Physical Chemistry
Initialed and dated laboratory notebook pages of the experiment must be submitted. While report sheets may be a joint effort, formal reports must be individually written. A schedule of reports and dates on which they are due is given in the course laboratory schedule. We highly recommend that reports be completed prior to the day of submission to allow time to proofread, and thus avoiding loss of points due to last minute problems. Lost data or the inability to print reports is not acceptable excuses for incomplete or missing reports. You will be informed when notebook pages will be collected before the report is due.
FORMAL LAB REPORT - Title and Author(s)
State the title of the experiment, your name, the date and your laboratory section number, if applicable. Also state the name of your lab partner(s). This information should be at the top of the first page.
FORMAL LAB REPORT – Introduction
The Introduction states the purpose of the study and introduces the reader with new ideas and topics. It also provides any background necessary to acquaint the reader with the problem being addressed, as well as providing the reader with references to previous relevant work.
Although a portion of a formal report, it is sometimes easier to view this section as a short essay, one in which the writer describes the importance of his work, and the possible application of his work to other areas of interest to the reader. As in an essay, the Introduction begins with a broad description of the principles being discussed in the report, and funnels down, becoming more specific along the way, to a statement of the specific objective of the study. It should acquaint the reader with the main topics and ideas discussed in the experiment, and should include definitions of key terms that are new.
In your Introduction, you will need to choose the relevant facts from your textbook, lab manual or other materials available to you, organize them in your own words, and present them in a logical order that highlights and supports the proposed experiment. Definitions of significant terms should be included. In general, your introduction should be two to three paragraphs long, concluding with the statement(s) of purpose.
FORMAL LAB REPORT - Experimental Information
Here you must give a concise description of what occurred in lab with sufficient detail to allow the reader to repeat the study. However unlike the audience for a laboratory text book, the audience for a formal report does not need to be told to wash the beakers or to insure there are no air bubbles in the buret tips. It is essential, therefore, that the writer be careful not to insult the intelligence of the audience when writing the Experimental section.
Another difference between formal Experimental sections and laboratory text books is that laboratory texts are generally written in second person past tense, i.e., “Open the lab drawer and take out your notebook.” Formal Experimental sections, on the other hand, are written in the third person, past tense, i.e., “The KHP solution was titrated with NaOH until a slight pink color permeated the solution.”
Preparing for this, it may help to summarize the procedure into a bulleted list of about five main procedural steps and then to convert the list to complete sentences. Be sure to mention any significant deviations from the procedure as stated in the lab manual.
In this section you should state significant information: amounts of starting materials and products, reagents used and their concentrations, instruments used, including their make and model, and significant observations of chemical reactions. Give a synopsis of what went on.
In general, remember that the audience would like to know what was done, not what to do. In a report you must write in complete sentences. Write in the third person past tense. One final note, be forewarned that step-by-step cookbook instructions are unacceptable in formal lab reports.
FORMAL LAB REPORT – Data and Calculations
The first step in completing this section is to use your data and generate any tables or graphs necessary for the analysis. This should be done in your lab notebook. Data may be graphed or tabulated. Whether the results are graphed or tabulated will depend on the data and the conclusions you draw. You need to use your judgment.
Then examine your data and select the appropriate, pertinent items for your formal report. Not everything in the data tables in your notebook will necessarily go into tables in your report. In your notebook you might have recorded initial and final buret readings, but in your report you would only state the volume of titrant used, i.e., the difference between the initial and final buret volumes. Once the reliability of your data has been assessed, you may tabulate your results. Having achieved this, you can discuss and interpret your results.
Conclusions you draw from your data must be presented in a clear, concise manner. Tables and figures (graphs are considered figures) should be integrated into your text, as you would find them in your textbook or in a journal article. You should introduce data tables and figures with words using complete sentences. Refer to figures and tables sequentially as they are introduced. Figures and tables should be identified with a separate series of number.
FORMAL LAB REPORT - Results and Discussion
This section is the meat of a formal report as it is where you demonstrate your understanding of the experiment and its results. It is also the most difficult to write, should take the most time, and is generally worth the most points in your score.
Begin this section with a statement of results. When you have finished working up your data, look it over to decide what conclusions may be drawn. State your results briefly, using the past tense. Write something about each table or figure, keeping in mind that they present the data but they do not state the results. Do not simply offer the data as your results. Be sure to introduce all your results in this section.
This section will also contain error analysis. Before one can draw conclusions from data, one must assess the precision and accuracy of the results. A result is only as good as the accuracy to which it was measured. To evaluate your data you must know how reliable it is. Acquiring data on a brand-new instrument does not mean that there is no error in the data, nor are computer calculated results error free.
There is always some error in your measurements. In the discussion of each error, a discussion of its effect on the experimental outcome/results should be included. Listed below are some common sources of error, all of which should be considered in assessing your data.
- Errors in measurement: It is easy to misread an instrument, particularly when using an analog device with several scales located on a single meter. Make sure you are reading the right scale. Make sure you know what the units are when recording data from an instrument. Other common measurement errors might be misreading a buret, not zeroing a balance, or incorrectly taring a balance. It is common to take 3-5 readings and use the standard deviation of the readings to estimate the uncertainty.
- Errors in Recording or Recopying: It occasionally occurs that numbers are transposed or decimal points lost when entering data in your notebook or copying them to a table. This type of error is hard to catch unless the number is totally unreasonable or well removed from an observed trend in the other measurements. Examples might be a pH of 23 or a series of repeated measurements where four out of five readings gave values between 0.2 and 0.8, but the firth reading gave 3.9; clearly there is a problem with the fifth measurement.
- Errors in Computation: Double check your calculations. Don’t assume your answer is wrong if it did not agree with your lab partner’s or the literature. Watch your units and unit conversions! Make sure they are consistent. Once you have completed your calculations, consider if the answer is reasonable. Always evaluate your calculations, particularly your units.
Once you have assessed the reliability of your data, you can discuss and interpret your results. You should first consider whether you accomplished what was proposed in the introduction and if your results were successful. What are the significant sources of error in the experiment? At least three procedural errors should be identified. How might they be minimized in the future?
Begin the “Results and Discussion” section with your interpretation of the results, and then perhaps a comparison of them with expected values. Always try to put a positive spin on your results if possible. You must also discuss the reliability of your data, how the reported uncertainty was determined and what its primary source was.
Things may go wrong in lab. However, even if your results are questionable, it is still possible to write a good lab report. Begin by stating what should have happened, then discuss what actually happened and why the experiment went wrong. Never begin your discussion with what went wrong. It is important that you demonstrate that you understand both what should have happened and what might have gone wrong. Note also that there is a big difference between a null result and a failure to get results.
FORMAL LAB REPORT - Conclusion
The purpose of the Conclusion section is to summarize the pertinent concepts discussed in the R&D section. Always begin your Conclusion by clearly stating your results and the “goodness” or significance of your results, and relating them to ideas presented in the introduction. In other words, if the objective of the study was to determine the percent calcium carbonate in an unknown sample, you should restate the percentage, with its uncertainty, in this Conclusion section.
Important observations may go in this section as well. Discuss the significance of the results. When possible, compare your results with literature values. Discuss significant errors and suggest improvements to the procedure or possible ideas for additional experiments that could further support your conclusion.
Then make a concluding statement(s) and relate your conclusion to the ideas presented in the introduction. Note: Stating that “overall the experiment went well” or that “I learned how to use a piece of equipment” are not strong conclusions.
The conclusion is not to be a lengthy discourse. One paragraph (about four to seven sentences) is the amount to be presented in conclusion.
FORMAL LAB REPORT – References
Always cite any literature and websites used in preparing your lab report. “Verbal Communications” may also be cited as such. The specific format used to cite references varies from journal to journal. You should always reference the lab manual. You may have others if you cite literature values or refer to your textbook for clarification of ideas.
Generally, all citations include the author’s last name and first initial, an abbreviated form of the journal title, the volume number, the first page number of the article and the year published. In citing a scientific paper, the title need not be given. In citing a book, begin with the author’s name, followed by the title of the book, the publisher, where published and the specific edition.
N. E. Triggs, M. Zahedi, J. W. Nibler, P. A. DeBarber and J. J. Valentini, J. Chem. Phys., 96, 1822 (1992).
J. A. Halstead, N. Triggs, A. L. Chu, and R. Reeves in Gas Phase Chemiluminescence and Chem-ionization, A. Fontijn (ed.), p. 307-334, North-Holland, (1985).
FORMAL LAB REPORT - Formatting Guidelines for lab reports
Clarity and Style
Observe the rules of good grammar, spelling, and punctuation. It is expected you will write in complete sentences. Proofread your report before you turn it in. There is no bigger turn off when grading a report than to find sloppy grammar and incorrect spelling. It sets the tone “expect the worst” and it will surely be reflected in your grade.
Reports must be typed and the use of a word-processor is encouraged. Use 1-inch margins, 12-point font for text and 1.5-line spacing. Choose a font that is easy to read.
Equations are presented as part of the sentence structure of the text and are numbered for future reference. All symbols are defined where first used. In formal reports, the first time an equation is presented, it is identified by a number. Each use of that equation is then referenced by that number, whether in the section introduced or in later sections. Sample calculations and results in any section may refer to equations previously introduced, or new equations may be presented. Equations are not grouped together, but are presented only when needed during the course of discussion.
A very useful tool for inserting equations into your documents is the equation editor available in many word processor packages.
"The molarity of HCl was calculated from Equation 1, where M and V are molarity and volume (mL) respectively. The mean molarity of HCl for the three trials was 0.0985 M, and the standard deviation, calculated with Equation 2, was ± 0.0002 M."
One figure that is often used in Chemistry is a graph. The type of graph you compose will depend on your data. Chemists most commonly use an x-y scatter plot with the dependent variable on the y-axis and the independent variable on the x-axis. All axes should be labeled – the reader does not necessarily know what you are plotting. And be sure to include the units for each axis, for example, “time (secs)” or “Fe3+ concentration (moles/liter)”. (You will be penalized if you leave axes labels out.) Pay attention to your axes’ scales and make sure your data fills the graph. The same data can look very different depending on how it is scaled. Always consider whether it is important to show that your data passes through the origin, or if it s more important that your data fills the scale.
Generally on an x-y scatter plot, you do not connect the dots, but simply draw the best straight line or curve through the data. If you plot more than one set of data on the same axis, you must include a legend to identify each series. Error bars are also important and helpful in judging the significance of the data. Usually these are only included for the dependent variable.
Figures (graphs) should be at least one-half of a page in size and regression statistics also included if calculated. They need to be numbered sequentially and include a relevant title. Ex: Figure 1. Density of Metal, Volume (mL) vs. Mass (g)
Tables are used when graphs are inappropriate and the data cannot be introduced in a single sentence of text. Each table should have a title at the top and a table number by which it can be cited in the text. Arrange your data by column rather than by row. It is much easier to read down than across. Do not include a column containing all the same numbers. Footnotes are frequently used to convey specifics about a subset of data within the table. Uncertainties in results should be presented with the data in the table. Tables are sequentially numbered, independent of Figures.
Well-known abbreviations, such as mL, M.W., etc., may be used without explanation. Otherwise, spell out the words the first time they are used, followed by the abbreviation in parenthesis, and use the abbreviation thereafter:
“Potassium hydrogen phthalate (KHP) was used as the primary standard.”
Many quantities have accepted symbols, i.e., pressure (P) or temperature (T). It is often convenient or efficient to define symbols for calculated or measured values.