Chemistry
Formal Lab Report Format
1) Heading: Include a title of experiment, name, partner’s name, date and period.
2) Abstract: Present a brief conceptual description of your experiment. Include the problem,
methods used, and major findings.
(NOTE: The abstract section is optional at the teacher’s discretion)
3) Introduction: This is the background section for your lab report. You should discuss the specific
topic being investigated. Include information that was researched as you developed your
experimental design and a brief historical perspective.
(NOTE: The introduction section is optional at the teacher’s discretion)
4) Materials: List all materials needed. Be specific.
(NOTE: The materials section is optional at the teacher’s discretion)
5) Procedure: Summarize the procedure you will follow during the experiment. This should be
numbered in a stepwise fashion or in a flow chart format. Procedures written in narrative or
paragraph form are not acceptable. Your procedure should be detailed enough that someone
could repeat the experiment using only your instructions. Include a diagram of your lab set-up.
(NOTE: The procedure section is optional at the teacher’s discretion)
6) Data:
Include any relevant data in table format. All data collected from your lab should be present in
this section.
7) Calculations:
Graphs - Follow standard graphing protocol. Make sure to use a best-fit curve through data
points.
Calculations – Show the formula that you used, and include one sample of each type of
calculation using your data (including error analysis calculations).
 Clearly label each calculation.
 Allow adequate space between calculations.
8) Conclusion - Your conclusion will serve two purposes.
a) Results - State the results of your experiment. Include your statistical error analysis. This
should correlate with your purpose or problem.
b) Error Analysis – Discuss the possible sources of error and their affect on your results.
Suggest changes in procedure or equipment that would decrease error.
Formal lab reports may be typed. Please use a 12 pt. font and double spacing on this document. If you
choose to turn in a hand-written report, it should be written in ink and printed neatly. If it is not
legible, it will be returned and you will be asked to type it.
Determination of the Density of Aluminum
Ms L Panning
w/ Mr J Lambrecht
2/11/2010 Period 4
Abstract: (This is used by AP Chem and college level courses – not required for general chemistry.)
In this lab, the density of aluminum was determined using two different methods to measure
volume. The volume of the block of aluminum was measured by both water displacement and
l·w·h measurements. The density of aluminum was found to be 2.681g/cm3 with an error of
0.704% using the method of water displacement, and 2.683g/cm3 with an error of 0.630% using
the method of calculated volume.
Introduction
Density, the ratio of mass to volume of a substance is an intensive property that depends on
temperature. In other words, it is a value that will not vary, regardless of the amount of matter
present in a particular sample, as long as the temperature remains constant. Densities of solids
and liquids are typically measured in units of g/cm3 and g/mL respectively, while the density of
gasses are measured in units of g/L. Reported values for the densities of solids and liquids are
usually determined at 25ºC and 1 atmosphere of pressure, while gasses are measured at 0ºC and 1
atmosphere of pressure. In this experiment we will determine the density of aluminum by using
two different methods – length x width x height measurement and water displacement.
Materials:
 Aluminum block
 String
 Metric ruler
 Water displacement container
 Analytical balance
 3-100mL beakers
Procedure:
1. Find and record the mass of the block of aluminum (Three trials).
2. Measure the length, width, and height of the aluminum block (Three trials).
3. Fill the water displacement container with tap water until water runs out of the spout.
4. Place a pre-massed beaker under the spout of the displacement container, and gently lower the
aluminum by the piece of string just until the entire block is submerged.
5. Find the mass of the water that was displaced.
6. Repeat steps 4-5 for a total of three trials.
Data:
Trial 1
Mass of aluminum (g)
Length (cm)
Width (cm)
Height (cm)
Mass of empty beaker (g)
Mass of beaker with water (g)
Mass of water displaced (g)
132.336
3.86
3.54
3.61
100.855
150.210
49.355
Trial 2
132.337
3.85
3.55
3.61
98.600
147.958
49.358
Trial 3
132.335
3.86
3.56
3.60
101.005
140.370
49.365
Average
132.336
3.86
3.55
3.61
n/a
n/a
49.359
Calculations:
Volume of Aluminum = length x width x height = 3.86cm x 3.55cm x 3.61cm = 49.328 cm3
Volume of Aluminum by water displacement =
mass of water
49.355 g

 49.355mL
density of water 1.00 g / ml
Density of Aluminum (calculated volume ) =
massAl
132.336 g
g

 2.683 3
3
volumeAl 49.328cm
cm
Density of Aluminum (water displacement)=
massAl
132.336 g
g

 2.681 3
3
volumeAl 49.355cm
cm
% Error =
TrueValue  ExperimentalValue
TrueValue
 100 
2.700 2.683
2.700
 0.630%
Conclusion Results -The density of aluminum was found to be 2.681g/cm3 with an error of 0.704% using
the method of water displacement, and 2.683g/cm3 with an error of 0.630% using the method
of calculated volume.
Error Analysis – There are several possibilities for the error in this lab. The most significant
error in the calculated volume was the limited precision of the ruler that was used. A
micrometer would allow the dimensions to be measured more accurately. It was also assumed
that the block of aluminum was precisely made, that is that parallel edges were all of equal
length. Slight variations in these lengths could cause us to calculate the volume incorrectly.
In calculating the volume by water displacement, more water could have been displaced
because of the string attached, resulting in a lower calculated density.
In both calculations, the true value for the density of aluminum was taken as 2.700 g/cm3. But
by definition, these densities are measured at 0ºC. At higher room temperatures, aluminum
expands slightly. Since the room temperatures were in the neighborhood of 20ºC, it would
reason that the volume of the aluminum was larger than it would have been at 0ºC. A smaller
volume would lead to a larger calculated value for the aluminum. To avoid this problem, we
could have placed the aluminum in ice water (0ºC) for several minutes and then measured the
dimensions. We also could have displaced ice water instead of tap water. The warmer tap
water could have expanded the volume of the aluminum, thus lowering the density. It is
possible that these changes would allow us to more accurately calculate the density of the
aluminum block.