The Laboratory Report for AP Chem
Each lab will be graded for the quality of the laboratory work that you have done. All labs will be worth 20-25
points. Sometimes you will work with a lab partner and other times you will work individually. In either case,
your lab write-up must be your own work. (You may discuss with peers, but you must write up the lab
separately.) It is important to keep all of your lab work because you may need to show your work to the
Chemistry Department at a college in order to obtain credit for the laboratory part of your Advanced Placement
Chemistry course.
General Guidelines for your report
o You will use your own notebook paper to write-up your labs. I suggest using a spiral notebook so that
the pages will stay together until you are ready to hand in the lab. (Make sure the pages rip out easily
from the spiral notebook.) We will provide graph paper when needed. Another option is to use a graph
paper spiral notebook—these are great for making data charts and graphs.
o Write in ink most of the time. If you make a mistake, just draw a line through your error and continue.
It is expected that some errors will occur. You cannot produce a perfect, error-free lab report. You may
use pencil for calculations if you wish.
o Do not use the first person or include personal comments.
o Spread out your writing. Take up as much room as you need. Write legibly.
o Once you have completed the lab, you will carefully rip out the notebook pages you used, attach any
separate handouts/graphs and hand the lab report in.
Laboratory Reports:
These labs can be complicated. It is vital that you are prepared when you come in on lab day. Before coming into
lab, you are expected to have…
o carefully read the lab instructions.
o written out the title, purpose and procedure
o completed the Advance Study Assignment (ASA) or Pre-Lab questions.
Your title, purpose, procedure, and ASA will be checked (or collected) at the start of the lab. Completed lab
reports will typically be collected at the close of the lab on lab day.
Include the following information in you laboratory reports: [20-25 pts total]
1. Title of the lab, lab partner(s), and date you performed the experiment.
2. Purpose: Give a brief statement of what you are attempting to do and the basic laboratory method you are
using. (Two to three sentences only)
3. Procedure: This should be an easy to follow bulleted or numbered list of the steps taken in the experiment.
This should include all of the major steps taken, but please do not include the lengthy details such as
quantities and helpful hints that are given in the lab manual. (Think of this as a procedural overview.
Generally, its length should be about a ½ page.)
4. Advance Study Assignment (ASA) or Pre-lab questions: Answer the questions completely. You must
show all work needed for calculations and every number written must have units.
5. Data/observations: Record all data directly either on the graph paper or on data tables that may be
provided. Organize your data in a neat, orderly form. Label all data very clearly. Use correct significant digits
and always include proper units. Use tables where appropriate.
6. Calculations and graphs: Show how calculations are carried out. (Give the equation used, how your values
are substituted into it and give the calculated values.) Calculated values should have proper significant digits
and units. Include percent error calculations if possible. If graphs are included in the lab, the following
instructions must be followed:
o Give a descriptive title for graph
o Vertical and horizontal axes should have labels and units clearly marked. Use a ruler to draw the axes.
(The controlled or independent variable is conventionally placed on the horizontal axis. The dependent
variable is graphed on the vertical axis. )
o The scales chosen should reflect the precision of the measurements. (If the temperature is given as 45.7°C
then you should be able to plot the value that closely.) Each axis can have a different scale but each axis scale
must be evenly spaced out.
o Do not label every division on the axes with a number—only label major divisions. All numbers on the
axes must have a corresponding hash mark.
o There should be an obvious small point on the graph for each experimental value. It is not necessary to
include the coordinates of each point. (However, there must be a data table with the specific experimental data.)
o If a linear relationship is represented, a smooth, best-fit line should be drawn. (Do NOT draw a line
connecting one point to the next. Instead draw a line that lies as close as possible to most of the points.)
7. Discussion of Theory: This section should include such information as: What theory was demonstrated in
this experiment? How was the purpose of the experiment fulfilled? Make sure you include a description of
all lab techniques, scientific terms and scientific concepts involved in this lab.
8. Experimental Sources of Error:
o Discuss your accuracy in this experiment. To do so, state percent errors if calculated and state whether
your experimental values were too high or too low?
o Discuss the precision in this experiment (What measurement limits your precision.)
o State systematic errors, weaknesses or limitations in the lab design. For each error, describe how the
error would affect the final results and how one could change the procedure to minimize the error.
Systematic errors refer to those aspects that would require a redesign of the lab, rather than simply redoing the lab.
Random errors such spilling, careless measurement, dirty glassware..etc exist in all experiments and should not be
mentioned as sources of error unless they cause a significant fault. Calculation mistakes are NOT experimental errors,
so double-check your calculations.
9. Post Lab Questions: For some labs, you may be given additional questions to answer or there may be
additional questions listed in the lab manual. Answer those here. Answer in such a way that the meaning of
the questions is obvious from your answer.