Density Lab
Purpose: To learn how to measure density
Materials:
10 mL and 100 mL graduated cylinders
250 mL beaker
balance
medicine dropper
tap water
Calipers
isopropyl alcohol
aluminum
zinc
chalk
Density Blocks
Procedure:
Part 1: Liquids
1.
2.
3.
4.
Find the mass of a 10 mL graduated cylinder. Take the mass out to the
nearest hundredth of a gram.
Fill the cylinder to the 9 mL level with tap water and read the volume to
two places past the decimal
Find the mass of the cylinder and its contents and record.
Repeat steps 1-4 using isopropyl alcohol.
Part 2: Irregular Solids
1.
2.
3.
4.
Obtain a sample of aluminum and find its mass. Take the value out to the
nearest hundredth of a gram.
Fill a 100 mL graduated cylinder to 30 mL with tap water.
Drop aluminum gently into the graduated cylinder. Record the new water
level to two places past the decimal.
Repeat steps 1-4 using zinc and chalk (calcium carbonate).
Part 3: Density Blocks
1.
2.
3.
4.
5.
6.
7.
8.
Obtain one of the labeled density blocks.
Determine the mass of the block to the nearest hundredth of a gram.
Record this mass in your data table.
Using the calipers, determine the volume of the block by accurately
measuring the length, width, and height of the block in millimeters.
Convert the block’s measurements from millimeters to centimeters.
Determine the volume of the block using your knowledge of volume.
Determine the density of the block.
Determine the identity of the block using your density information.
Repeat steps 1 – 7 for 5 more blocks.
Part 4: Multiple Blocks
1.
2.
3.
4.
5.
6.
7.
8.
Obtain 4 density blocks of the same substance (look at the letters).
Record the letter of the substance in your data table
Measure the mass of one block to the nearest hundredth of a gram and
record.
Determine the volume of the one block using length, width, and height
measurements.
Measure the mass of 2 blocks to the nearest hundredth of a gram.
Record.
Place the 2 blocks next to each other and determine their volume using
the length, width, and height measurements.
Repeat steps 1 – 6 for 3 blocks.
Plot your mass and volume data for 4, 3, 2, and 1 blocks on a graph
(volume is on the x axis, mass is on the y axis).
Results and Calculations
Create a data table for all the data you have collected. It should include the
mass and volume of each substance you’ve investigated (water, isopropyl
alcohol, aluminum, zinc, chalk, and each density block).
The table below indicates the “accepted density value” for each of the
substances:
Substance
Density (g/mL)
Water
Isopropyl alcohol
Aluminum
Zinc
Calcium carbonate (chalk)
Acrylic
Brass
Copper
Oak
Pine
Polypropylene
PVC
Steel
1.00
0.79
2.70
7.13
2.83
1.1 – 1.2
8.4 – 8.8
8.96
0.60 – 0.90
0.35 – 0.50
0.91 – 0.94
1.39 – 1.42
7.9
% Error = | accepted value – experimental value |
accepted value
x
100
Post – Lab Conclusion
1)
What is the formula for calculating density?
2)
Calculate the density for each of the substances you examined in lab
today (water, alcohol, chalk, aluminum, zinc, density block) Show All
Work For Full Credit!! **Be sure to include units!!
3)
Calculate the % error of your density calculation using the accepted
density values and the following equation:
% Error = | accepted value – experimental value |
accepted value
x
100
4)
Use your percent error calculations to discuss how well (or not so well)
each part of your experiment went. Use the values to describe both the
accuracy and precision of your calculations.
5)
Using information from your graph in Part 4, determine the correct answer
to each of the following questions:
a)
As volume increases, mass (increases, decreases, remains the same)
b)
As volume decreases, mass (increases, decreases, remains the same)
c)
Calculate the slope of your line. Show your calculation. (∆y / ∆x) Include
units!!
d)
What does the slope of the line on your graph represent?
e)
Compare the slope of your line to the density of the substance you
measured. What do you notice about these values? Explain.
f)
As the mass and volume of the same pure substance increases, the
density of that substance (increases, decreases, remains the same).
Additional Density Questions
DIRECTIONS:
Solve the following problems on density and include them
with your post lab work.. Show ALL work and include the correct units in order to
receive full credit. Please write the original question, the calculation, and final
answer in your lab notebook. Please draw a box around your final answer.
1.
What is the density of 8.06 g of beeswax if it has a volume of 8.50 cm3?
2.
What is the density of a piece of concrete that has a mass of 8.76 g and a
volume of 3.07 cm3?
3.
Cobalt has a density of 8.90 g/mL. What volume would it occupy if it has a
mass of 17.8 g?
4.
Calcium chloride has a density of 2.50 g/mL. What is the volume of 7.91 g
of this substance?
5.
Limestone has a density of 2.72 g/cm3. What is the mass of 24.9 cm3 of
limestone?
6.
Ammonium magnesium chromate has a density of 1.84 g/mL. What is the
mass of 7.62 mL of this substance?