Objective: To calculate density.
- Volume of a cube or block = length x width x height
- Volume of irregular shaped object = use water
displacement
Density
density = mass/volume OR
d = m/v
d=
Example: An object has a mass of 22 g and a
volume of 11 cm3. What is the density of this
object?
Example #1
1. An object has a mass of 18.9 g and a volume of 7.0
mL. What is the density?
2. What is it? (refer to table of densities on page 17)?
3. Will it float?
Example #1: Answer
1. An object has a mass of 18.9 g and a volume of 7.0
mL. What is the density?
d = m/v = 18.9 g / 7.0 mL = 2.7 g/mL
2. What is it? (refer to table of densities on page 17)?
Aluminum
3. Will it float?
2.7 g/mL > density of water (1.0 g/mL) SINK
Example #2
1. A liquid has a mass of 4.743 g and a volume of 6.0
mL. What is the density?
2. What is it (refer to the table of densities on page
17)?
3. Will it float?
Example #2: Answer
1. A liquid has a mass of 4.743 g and a volume of 6.0
mL. What is the density?
d = m/v = 4.743 g/6.0 mL = 0.79 g/mL
2. What is it (refer to the table of densities on page
17)?
ethanol
3. Will it float?
0.79 g/mL < density of water (1.0 g/mL)  float
Example #3
What is the density of a cube with a length of
5.0 cm and a mass of 26 g?
Example #3: Answer
What is the density of a cube with a length of
5.0 cm and a mass of 26 g?
Volume = length x width x height
Volume = 5.0 cm x 5.0 cm x 5.0 cm = 125 cm3
Density = m/v = 26 g/125 cm3 = 0.21 g/cm3
Example #4
An irregularly shaped stone was lowered into a
graduated cylinder holding a volume equal to
2.0 mL. The height of the water rose to 7.0
mL. If the mass of the stone was 25 g, what
was the density?
Example #4: Answer
An irregularly shaped stone was lowered into a
graduated cylinder holding a volume equal to
2.0 mL. The height of the water rose to 7.0
mL. If the mass of the stone was 25 g, what
was the density?
Volume = 7.0 mL – 2.0 mL = 5.0 mL
Density = m/v = 25 g / 5.0 mL = 5.0 g/mL
Density Equation
• Density = Mass/Volume
d = m/v
• Mass = Density x Volume
m=dxv
• Volume = Mass/Density
v = m/d
Example #5
If the density of an object is 8.7 g/mL and the
volume is 15 mL, what is the mass of the
object?
Example #5: Answer
If the density of an object is 8.7 g/mL and the volume
is 15 mL, what is the mass of the object?
Mass = d x v
Mass = 8.7 g/mL x 15 mL
Mass = 130.5 g  130 g
Example #6
If the density of an object is 3.6 g/mL and the
mass is 60.0 g, what is the volume of the
object?
Example #6: Answer
If the density of an object is 3.6 g/mL and the mass is
60.0 g, what is the volume of the object?
Volume = m/d
Volume = (60.0 g) / (3.6 g/mL)
Volume = 16.67 mL  17 mL
Example #7
If the density of an object is 5.5 g/mL and the
mass is 1.2 kg, what is the volume of the
object?
Example #7: Answer
If the density of an object is 5.5 g/mL and the mass is
1.2 kg, what is the volume of the object?
Volume = m/d
Volume = 1200 g/(5.5 g/mL)
Volume = 218 mL  220 mL
Example #8
5.0 mL of the ethanol has a mass of 3.9 g, and
5.0 mL of benzene has a mass of 4.4 g. Which
liquid is denser?
Example #8: Answer
5.0 mL of the ethanol has a mass of 3.9 g, and 5.0 mL
of benzene has a mass of 4.4 g. Which liquid is
denser?
Ethanol
Benzene
Density = Mass/Volume
Density = Mass/Volume
Density = 3.9 g/5.0 mL
Density = 4.4 g/5.0 mL
Density = 0.78 g/mL
Density = 0.88 g/mL
Benzene is more dense.