Experiment #3 / Unit 1
How Dense is it?
Introduction:
Density is a commonly studied property of matter. An object’s density tells
you about the concentration of matter in that object. Something that is very
dense will have a lot of matter (mass) in a small amount of space (volume). An
object with low density will have less matter in the same amount of space. A cork
will float on water because it is less dense than water. A helium-filled balloon will
float upward because it is less dense than the surrounding air. Density is
determined by taking a ratio of two common measurements: mass and volume.
The mass of a substance is divided by its volume (d = m/v) so that we have an
idea of how much “stuff” is in a certain amount of space. Usually these
measurements are taken in grams and milliliters so that the calculated density is
in g per mL (g/mL). However, other units of mass and volume are sometimes
used. In this experiment, we will determine the densities of various liquids and
solids. This will allow us to do the following:
 Learn about the important concept of density.
 Practice making correct measurements with the instruments.
 Practice using significant figures to make correct calculations with our
measurements.
Procedure:
 Remember to read to the first estimated digit on all measurements.
Concentrate on making measurements now - save calculations for later.
Calculators can go home…..instruments can’t.
A. The Density of Water
1. Mass a 125 mL Erlenmeyer flask with a balance.
2. Pour about 10.0 mL (measure and record the correct volume) of water
in a 25 mL graduated cylinder. Add this to the flask and remass the
flask. Obtain the mass by difference.
B. The Density of an Unknown Liquid
1. Obtain about 10 mL of an unknown liquid (your choice) in a small
beaker and record the letter of the unknown.
2. Mass a 125 mL Erlenmeyer flask with a #5 stopper in the top. Pour
about 10.0 mL (measure and record the correct volume) of the liquid
in a 25 mL graduated cylinder. Add this to the flask and remass the flask.
Obtain the mass by difference. Return the unknown liquid to its container.
C. The Density of a Solid
1. Mass a dry solid of your choice: lead (fishing sinker), brass, steel, rubber,
aluminum, glass (marble), vinyl plastic (grey), or polyethylene plastic (white).
Chemistry I
Cary Academy
W.G. Rushin
1
2. Fill a 100 mL graduated cylinder about half full with water. Record the
initial volume. Slide the solid into the graduated cylinder and
record the new level of the meniscus.
D. The Density of a Penny
1. Obtain 10 pennies which are a set from either pre-1982 or post-1983.
Make sure that they are clean and dry.
2. Mass the set of pennies.
3. Obtain the total volume of the pennies by water displacement.
E. The Density of Wood
1. Obtain a piece of wood and measure its mass.
2. Measure the length, width, and height (thickness) with a ruler.
F. The Thickness of Aluminum Foil
1. Obtain a rectangular piece (approx. 10 x 20 cm) of aluminum foil.
Measure the length and width in cm.
2. Fold the foil and mass on a balance.
3. The density of aluminum is 2.70 g/cm3. Using this information and your
recorded data, you will be able to calculate the thickness of the aluminum foil.
G. Is My Ring Pure Gold?
1. Make appropriate measurements.
H. Will a Bowling Ball Sink?
1. Make appropriate measurements & test your prediction.
Data and Calculations:
A. The Density of Water
Data:
 mass of empty flask
 volume of water
 mass of flask and water
Calculations:
1. Mass of water
2. Density of water
3. Find percent error for density
B. The Density of an Unknown Liquid
Data:
 mass of flask and stopper
 volume of liquid
 mass of flask, stopper, and liquid
Calculations:
1. Mass of liquid
2. Density of liquid
3. Find percent error for density
C. The Density of a Solid
Data:
 mass of solid
 initial volume
 final volume
Calculations:
1. Volume displaced by solid
2. Density of solid
3. Find percent error for density
Chemistry I
Cary Academy
W.G. Rushin
2
D. The Density of a Penny
Data:
 pre-1982 or post-1983 set?
 mass of pennies
 initial volume
 final volume
Calculations:
1. Average mass of penny
2. Total volume displaced by pennies
3. Average volume of a penny
4. Average density of a penny
5. Find percent error for density
E. The Density of Wood
Data:
 length, width, and height
 mass of block
Calculations:
1. Volume of block
2. Density of block
3. Find percent error for density
F. The Thickness of Aluminum Foil
Data:
 length and width of foil
 mass of foil
 density of foil
Calculations:
1. Thickness of foil
2. Find the radius of an aluminum atom.
Determine the thickness of the foil in
atoms. Assume the atoms are stacked.
G. Is My Ring Pure Gold?
Data:
 you decide
Calculations:
1. You decide
H. Will a Bowling Ball Sink?
Data:
 you decide
Calculations:
1. You decide
Calculations and Questions:
1. Ether floats on water and mercury sinks (See
the figure ). State where the following would
come to rest after being dropped into the
graduated cylinder:
a. a diamond (d = 3.5 g/mL)
b. a platinum ball (d = 21.4 g/mL)
c. an oak ball (d = 0.65 g/mL)
d. a piece of wax (d = 0.90 g/mL)
2. Is the ring pure gold? Using your results, explain
how you were able to reach a conclusive
decision.
3. A rectangular jade block has a mass of 146.25 g
and measures 10.00 cm by 3.00 cm by 1.50 cm.
What is the density of the jade.
4. Find the thickness of a sheet of gold foil having a mass of 2.00 g and
measuring 3.00 cm by 10.0 cm. The density of gold is 19.3 g/cm 3.
Chemistry I
Cary Academy
W.G. Rushin
3
Lab Report #1.3: (67 pts)
 title page (1 pt)
 abstract (7 pts)
 procedure sheet (1 pt)
 data and calculations (in order by sections) (23 & 27 pts respectively)
(Data shown in box format with generic headings, calculations worked
beneath each table, label calculations, show work including equations and
units, use your sig fig rules, do not need to show long divisions. Student
produced examples will be shown in class.)
 calculations and questions (#2-4 - show work) (8 pts)
Chemistry I
Cary Academy
W.G. Rushin
4