Writing a Formal Honors Chemistry Laboratory Report
Some laboratory work will require authoring a formal Laboratory Report. Formal reports include detailed
background information on the chemical or physical process being studied and your hypothesis, ALL
information needed to run the experiment(s), data generated in tabular and/or graphical form, sample
calculations, and detailed analysis of the data gathered. This results in conclusions generated, error
analysis performed, and a conclusion written that completes the report. This document will help you
understand what is required to write a formal Laboratory Report for this class.
Step One: Be Prepared
Never begin any experiment unless you understand the overall purpose of the experiment and the reasons
for each operation involved. This requires studying (not just reading!) an experiment before coming to the
laboratory. You will find that not only will your performance in the laboratory be better if you are well
prepared, but you will also benefit more from the experiments, which in turn will make for a better report.
Also, perform your own research on the chemical or physical phenomenon being studied. This will help
your understand why you are performing the lab and also help with the Hypothesis/Theory portion of the
report. Have questions ready to ask before the lab so you make the most of your lab experience. Make
data tables prior to the lab.
Step Two: The Lab
Now it’s time to perform the lab. This will require collecting data. Your data tables should already be in
your marble notebook. You can make drafts of your data tables on other paper first, but by the time the
lab starts, your data tables should be in your lab notebook in INK. Data should be written in the table(s)
in the same color ink. If you make a mistaake mistake, simply draw a single line through your mistake
and continue writing your lab – DO NOT ERASE. Maybe your mistake wasn’t one at all. Now you have
that original data to use instead of erased forever. In addition, record any observations you have during
the experiment. Also make sure you write down WHEN during the experiment these took place. These
should be written directly below the data tables.
Part Three: Lab Report
Formal lab reports can be of two types: Individual and Group
• Individual: The lab group performs the experiment together, but the report is written individually.
Make sure EVERYTHING is done independent of other lab partners; copied/plagiarized parts will
result in a ZERO for ALL parties (original work/idea and copied work/idea).
• Group: Each member participates in the write-up of the lab report. Group members will specify
which parts where they will take primary responsibility (place that person’s name in parentheses
directly after the title of the lab report section). But note, in this case, you should have your report
completed at least one day before it is due so each member can proofread the entire report. All
group members are responsible for a cogent lab report.
Your lab report must include the following material in the following order; each section should be labeled:
Your Name
Lab Partner’s Names
Title: Be descriptive and don’t worry if the title seems a little long. Underline the title.
Below Expectations
Salt Solution Density Lab
Meets or Exceeds Expectations
Determination of the Relationship Between the
Density and Concentration of Sodium Chloride
Solutions
Learning Objective:
This is a one-sentence description of “why” you are doing this lab. It describes its relationship to the topic
being discussed in class. This is the scientific reason for demonstrating a chemical or physical
phenomenon. Include the name of the “law”, “chemical property” or “principle” you will illustrate by
performing the assigned task.
Hypothesis:
State your hypothesis – this should be backed-up from what you learn in the Theory/Background section.
Theory/Background:
This is an elaboration or summary of the object/purpose or history of the experiment. This must include
the full wording of the “law”, “chemical property” or “principle” that you are illustrating by performing
the laboratory experiment. Equations, proportions and mathematical explanation that accompany each
law, chemical property, or principle must be included. Be precise and concise. This is where you tell me
what you know about this topic! This section is designed to enhance your research capabilities and
broaden your scope of knowledge that is available to you in the written form. You must use two credible
sources (not Wikipedia) and cite the information in MLA format in the References section. This should
be about one paragraph.
Also, many labs will demonstrate a particular type of chemical reaction that is described by a chemical
equation. If a reaction occurs between two or more chemicals, a balanced equation must be shown in this
section. Forms of all chemicals should be noted using subscripts ((s) = solid, (aq) = aqueous solution,
(g) = gas, (l) = liquid). Subscripts and superscripts must be used.
Sample: Mg(s) + 2HCl(aq) → MgCl2(aq) + H2(g)
Procedure:
Summarize the procedure you followed in the lab in one or two paragraphs. Be more specific if you
created the procedure for the lab. Copying/Pasting the procedure will result in a zero. The procedure
should be in third person.
Below Expectations
“Measure out 10.00 mL of the 5% NaCl solution
with a pipet and a graduated cylinder, being careful
not to lose any solution. Place the graduated
cylinder on the analytical balance and determine its
mass to three decimal places. Record the mass in
the data table.”
Meets or Exceeds Expectations
“Use an analytical balance to determine the mass of
10.00 mL samples of each of the solutions of
known concentration.”
Data and Observations:
The data table(s) and observations should be transposed to the electronic document. Ensure that all data
tables are labeled with what the rows/columns represent and the unit associated with the measurement.
Label each table as “Table X.”
Data Table 1:
Meets or Exceeds Expectations
Below Expectations
5% solution = 10.012 g
10% solution = 10.180 g
15% solution = 10.230 g
Concentration (%)
5
10
15
Mass (g)
10.102
10.180
10.230
Data Table 2:
Measurement
Mass
Mass of dry test tube
25.0 g
Mass of test tube and magnesium oxide
28.3 g
Mass of magnesium oxide
3.30 g
Lists of data is not a data table.
Observations should be made in complete sentences. Observations are what you witness using your
senses and not based on calculations.
Calculations:
If there are any mathematical calculations (no matter how insignificant they may seem), that are needed to
complete the analysis of the lab data, they should appear in this section. There should be a sample
calculation for every equation used in the lab exercise. This should be done in an equation editor. These
are often equations that reflect the law, or property being examined through the lab exercise. Each sample
calculation should include the following items in the following order:
a.
b.
c.
d.
e.
A heading stating what you are going to calculate.
An equation in a familiar or basic form.
An algebraic solution of the equation for the desired variable quantity.
Substitution of known values with sample units from your data.
Numerical answer using proper units.
Sample:
a) Calculation of the number of moles of gas obtained in step #4.
b) 𝑃𝑉 = 𝑛𝑅𝑇
c) 𝑛 =
d) 𝑛 =
!"
!"
(!.! !"#)(!!)
(!.!"#$ !"#$/!"#$)(!"#!)
e) 𝑛 = 0.16 𝑚𝑜𝑙
Graphs:
Graphing the results of an experiment involving two variables helps to make the relationship of the
variables more obvious. Make the graphs large enough to show detail and accuracy. Each graph should
have a title/header that states what is being graphed. Each axis should be labeled as to the measurement
being graphed. Units for each measurement should be stated on each axis.
A trendline should be drawn through the plotted points. This may be a straight line, curve, etc., depending
upon the mathematical function that is being graphed. Examine your equation and mathematical
proportion that exists between your plotted values to determine the correct shape of your graph. Use color,
different shaped points, and a legend to enhance the clarity of your graphs. Label each graph “Figure X:”
so you can easily reference it in your analysis.
Sample:
Figure 1:
Analysis:
The analysis section of your laboratory report should contain the answers to all questions posed in the
“Questions” section of your laboratory. Number these questions and answer them using full and complete
sentences. No one-word or one-number answers will be accepted. If asked to calculate something in these
questions, they must be done using the same method as the “calculations” section of your lab report. In
addition, you may be asked to address other issues connected with the experiment, such as experimental
error and the relationship between the experiment and other aspects of science.
𝑃𝑒𝑟𝑐𝑒𝑛𝑡 𝑒𝑟𝑟𝑜𝑟 = | 𝐴𝑐𝑐𝑒𝑝𝑡𝑒𝑑 𝑣𝑎𝑙𝑢𝑒 – 𝐸𝑥𝑝𝑒𝑟𝑖𝑚𝑒𝑛𝑡𝑎𝑙 𝑣𝑎𝑙𝑢𝑒 |
𝑥 100
𝐴𝑐𝑐𝑒𝑝𝑡𝑒𝑑 𝑣𝑎𝑙𝑢𝑒
Conclusion:
One or two sentences determining whether your hypothesis was proved/disproved based upon your data.