Advanced Placement Chemistry
LAB MANUAL
The AP Chemistry Exam includes inquiry style and laboratory skill based questions that
require students to draw from their own experiences with materials and to use critical thinking
skills that are enhanced by participation in weekly lab activities. Statistics show that high
scores on the AP Chemistry exam are directly correlated to the amount and quality of student
lab work. Therefore, when a student is absent on the day of a lab, it is very important that
arrangements to make up the lab be made as quickly as possible (before the chemicals get
thrown away). Labs will be available for make-up for only one week after they have been
performed by the class.
In the Laboratory
Students who wish to participate in lab are expected to come to the lab periods wearing
clothing that is in accordance with the Northern Highlands Safety Contract. Mandatory lab
attire includes safety goggles (provided) and closed-toe shoes for the entire duration of the
laboratory experiment and clean up procedures. Contact lenses and shorts are discouraged but
not prohibited. Also in accordance with the Safety Contract, all food and beverage products
are banned from lab. Gum chewing is not permitted during lab.
Prior to the lab period, students are expected to complete a pre-lab assignment. This
assignment entails reading the current lab assignment and setting up the lab notebook
following appropriate procedures (see below). When actually entering the laboratory, all
belongings should be placed on the window side of the room. Students may only bring their
lab notebook and a pen to the lab station. All experiments are to be performed in a standing
position to increase alertness, response-time, and measuring ability.
Grades
Laboratory grades are comprised of two separate portions. The first grade is assigned while
in the laboratory for compliance with safety regulations, proper chemical technique,
preparation for the experiment, and clean-up procedures. The second portion of the grade is
determined by the individual lab report. While experiments will be completed with a partner,
each student is graded individually for their lab performance and reports.
Additionally, a separate grade will be given for lab notebook upkeep. Lab notebook checks
can take the form of an unannounced spot check before a lab or as a formal collection and
inspection. A lab notebook check will take place at minimum once a semester.
Broken Glassware
The glassware and other equipment used in the lab should be respected at all times. In the
event of broken glassware or equipment, the teacher must be notified immediately and the
glass fragments disposed of into the broken glass container. Broken glass should NEVER be
placed in the regular trash can as that can lead to serious injury. ALWAYS use the dustpan
and broom to sweep up shards. The science department policy states that students are
responsible for paying the replacement fee for any equipment that they have broken or
damaged in the laboratory.
Lab Notebook and Reports
Students are expected to purchase an appropriate lab notebook for experiments separate from
the classroom notebook. The appropriate book is a composition notebook with a sewn
binding (NOT spiral bound). It may have either grid lines or regular paragraph lines. A
carbon copy lab notebook, while acceptable, is not necessary since your reports will not be
hand-written.
A lab report is completely separate from the lab notebook. The lab notebook is a tool used
during lab containing your methods and a record of your lab data. It is very important that
your work is original. You may not copy and paste any part of your lab report from another
source. This includes the lab sheet.
Lab Notebook Format
All students are expected to maintain an organized, yet hand written, record of their
laboratory experiences, following a traditional scientific format. Some important ground rules
for the use of the notebook include:
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Entries must be made at the time of the experiment, not afterwards.
All entries should be made in blue or black ink, NOT pencil.
Use of white out or correction tape is strictly prohibited.
The first two pages should be used for a table of contents.
All pages, front and back, should be numbered for easy reference.
No loose pages should be wedged into the notebook.
Heading, objective, procedure, safety, and data sections comprise an entry.
Every entry should end with your signature.
Basic format for each lab entry:
Page #
Date
Title
Partners
Objective: Statement about what you hope to achieve
Procedure: Outline the essential steps necessary for completion of
the experiment. Include diagrams of any unusual or new
apparatus/equipment for your reference.
Safety: Research the MSDS for each chemical used in the lab.
Provide a chemical structure and a summary of the hazards.
Data/Observations: All data should be recorded during lab into a
table. You might prepare the table before the lab period.
Your Signature
Lab Report Format
A lab report is a careful analysis of your data, written formally, including calculations and
formatted data tables. Although laboratory experiments may be completed with collaboration
of a lab group comprised of approximately three students, it is expected that each individual
complete his/her own summative lab report at the end of the experiment. A formal lab report
has several sections: heading, abstract, background information, materials and methods,
data/observations, calculations, and conclusions. These sections must come in the correct
order.
Heading: Put your name and the date the experiment was performed (not the date you are
writing the report!) in the top right corner of the lab report. Hit enter twice. Center and type
the title of the lab report. Hit enter twice, and begin the lab report.
Abstract: While it may be helpful to write this section last, it should be placed at the start of
the lab report. It is a brief summary of what was being studied, the methods used to do so,
and the results of said experiment…kind of like the synopsis you’d find on the back of a
novel. NEVER use the 1st person voice. See the following example:
The amount of copper used to create brass 22-shell bullet casings was studied
by examining the relationship between the absorbance of electromagnetic radiation at
620 nm and concentration of copper(II) nitrate created by dissolving the brass casings
in nitric acid. A Spec 20 colorimeter was used in order to determine the absorbance
of each casing solution. The relationship between concentration and absorbance was
found to be linear, in perfect correspondence to Beer’s Law. The average percent of
copper from four trials was graphically determined to be 68.32 %.
Background Information: Briefly explain underlying principles or theories that help to
explain the processes observed in the reaction. Include any mathematical equations and
balanced chemical equations for the processes that you use in the experiment. Each time you
include an equation, reference it in the text, then on the next line label it numerically to the
left in bold. Go to the center of the line and insert the equation. Each time you include a
figure or diagram do the same as you would with an equation, only keep a separate numbering
system. See the following example:
Beer’s Law, equation 1, is a relationship between concentration and
absorbance, in which absorbance is equal to the product of the molar absorbtivity,
path length, and concentration.
Equation 1
A= bc
Molar absorptivity refers to the amount of light absorbed by the sample per
concentration mole of sample present, and path length is a measure of how much
sample is present. A colorimeter, seen in figure 1, can be used to measure absorbance.
The colorimeter essentially shines light of known wavelength and intensity and detects
how much of that light travels through the sample. The amount of transmitted light is
related to the amount of absorbed light…etc.
Figure 1
Materials and Methods: Summarize briefly what you did and used in the lab using
paragraphs and full sentences. Step by step instructions, while appropriate in a lab notebook,
are insufficient in a lab report. Bullet points should NEVER be employed! Do not write out
a separate list of materials used. Include any diagrams of complicated or novel glassware and
equipment set-up. Once again, NEVER use the 1st person voice. See the following example:
Four brass bullet casings were used to create four separate solutions of
copper (II) nitrate. A single brass bullet casing, after being massed, was dissolved
into 50 mL of concentrated nitric acid. A standard set of four copper (II) nitrate
solutions were also created in the concentrations 3.0M, 1.0M, 0.5M, and 0.1M in 50
mL volumetric flasks. A Spec 20 colorimeter was used to measure the absorbance of
each solution. The Spec20 was allowed to warm up for 30 minutes before use, and
was calibrated at a wavelength of 620 nm. A standard cuvette was used to load the
sample into the colorimeter, and the measurement was taken 3 seconds after loading.
The concentrations of the brass bullet casings were determined graphically from the
data.
Data: Include your data in tabular form; excel sheets can be inserted into word documents,
but remember to make the lines visible! Remember to use units on all measurements and to
record all observations made during the experiment. Be careful that your data is actual data,
and not the result of your calculations. If you make a graph from the data, you must still
include the data table. Graphs must be marked with a graph title and axes labels.
Calculations: Show a sample calculation for each type required. Use labels and words to
make what you are doing very clear. After the sample calculation is shown, you can use a
table to record the other values you have calculated without showing each step of the
calculation. Remember to always use the correct number of sigfigs and units!
Discussion: Your ability to write a sophisticated analysis of the experiment is an indication of
your understanding of the subject. Therefore, this section should not be fragmentary,
expansive, or excessively critical of apparatus or equipment. Be sure to mention your
calculated results in this section. Though the answer to your objective is probably shown in
the calculations section, you should use words to state the result in the conclusion. Always
consider what implications your results have. Discuss the meaning of your results. Compare
your results for accuracy and precision using statistical analysis when possible. Finally, every
lab should have a thorough error analysis section. It is not enough to simply state any
mistakes made during the lab. You must account for the affects of error on the experiment,
and explain how results might have been different if not for the error. Again, NEVER use the
1st person voice. See the following example:
The average percent of copper in the brass shell casings was determined
graphically to be 68 %. Brass, an alloy of copper and zinc, is the most malleable
alloy since its components are also quite malleable. Typically brass used in the
manufacture of ammunition contains 70.0% brass and 30.0% zinc. The results found
seem to correlate with this expectation, though a slight deviation is noticed. This
deviation from the expected value could be due to the method used to create the brass
bullet copper solution. The solution was created in a beaker, and a graduated
cylinder used to measure the nitric acid. Had a volumetric pipette and a volumetric
flask been employed, the amount of error in measurements could have been decreased
by 5%, since more significant figures could have been used in the answer.
Lab Report Submission
To submit a lab report, you should type the report in a word document. When you name the
document for saving, put the number of the lab and your last name, first initial in caps. As an
example, I would name my first lab report: 1VOLPEC
Once you have saved the document with the correct name, share the document with me on
Google Drive. I will read and comment on your lab and email you to let you know when the
comments are ready. You should save the returned copies of the lab for college admissions
directors. Some schools will only allow you to test out of the lab component of Intro Chem if
you have records of lab experience (such as a portfolio of graded lab reports and a lab
notebook).