1. Chapter 1 Measurements 1.7 Density
Copyright © by Pearson Education, Inc.
Publishing as Benjamin Cummings

2. Density Density Compares the mass of an object to its volume.
Is the mass of a substance divided by its volume.
Density expression
Density = mass = g or g = g/cm3
volume mL cm3
Note: 1 mL = 1 cm3

3. Densities of Common Substances

4. Learning Check
Osmium is a very dense metal. What is its density in g/cm3 if 50.0 g of osmium has a volume of 2.22 cm3?
1) g/cm3
2) g/cm3
3) g/cm3

5. Solution Given: mass = 50.0 g volume = 22.2 cm3
Plan: Place the mass and volume of the osmium metal
in the density expression.
D = mass = g
volume cm3
calculator = g/cm3
final answer (2) = g/cm3

6. Volume by Displacement
A solid completely submerged in water displaces its own volume of water.
The volume of the solid is calculated from the volume difference.
45.0 mL mL
= 9.5 mL = 9.5 cm3
Copyright © by Pearson Education, Inc.
Publishing as Benjamin Cummings

7. Density Using Volume Displacement
The density of the zinc object is
then calculated from its mass
and volume.
mass = g = 7.2 g/cm3 volume cm3
Copyright © by Pearson Education, Inc.
Publishing as Benjamin Cummings

8. Learning Check
What is the density (g/cm3) of 48.0 g of a metal if the level of water in a graduated cylinder rises from 25.0 mL to 33.0 mL after the metal is added?
1) g/cm3 2) 6.0 g/cm3 3) 380 g/cm3
33.0 mL
25.0 mL
object

9. Solution Given: 48.0 g Volume of water = 25.0 mL
Volume of water + metal = 33.0 mL
Need: Density (g/mL)
Plan: Calculate the volume difference. Change to cm3,
and place in density expression.
33.0 mL mL = mL
8.0 mL x 1 cm3 = cm3
1 mL
Set up Problem:
Density = g = g = 6.0 g/cm3
8.0 cm cm3

10. Sink or Float
Ice floats in water because the density of ice is less than the density of water.
Aluminum sinks because its density is greater than the density of water.
Copyright © by Pearson Education, Inc.
Publishing as Benjamin Cummings

11. Learning Check
Which diagram correctly represents the liquid layers in the cylinder? Karo (K) syrup (1.4 g/mL), vegetable (V) oil (0.91 g/mL,) water (W) (1.0 g/mL) K W V V W K V W K

12. Solution vegetable oil 0.91 g/mL V W K 1) water 1.0 g/mL
Karo syrup 1.4 g/mL V W K

13. Density as a Conversion Factor
Density can be written as an equality.
For a substance with a density of 3.8 g/mL, the equality is
3.8 g = 1 mL
From this equality, two conversion factors can be written for density.
Conversion 3.8 g and mL
factors 1 mL g

14. Learning Check
The density of octane, a component of gasoline, is g/mL. What is the mass, in kg, of 875 mL of octane?
1) kg
2) 614 kg
3) kg

15. Solution 1) 0.614 kg Given: D = 0.702 g/mL V= 875 mL
Unit plan: mL  g  kg
Equalities: density g = 1 mL
and 1 kg = 1000 g
Setup: 875 mL x g x 1 kg = kg
1 mL g
density metric
factor factor

16. Learning Check
If olive oil has a density of 0.92 g/mL, how many liters of olive oil are in 285 g of olive oil?
1) L
2) L
3) 310 L

17. Solution 2) 0.31 L Given: D = 0.92 g/mL mass = 285 g
Need: volume in liters
Plan: g  mL  L
Equalities: 1 mL = 0.92 g and 1 L = 1000 mL
Set Up Problem:
285 g x 1 mL x L = L
0.92 g mL
density metric
factor factor

18. Learning Check
A group of students collected 125 empty aluminum cans to take to the recycling center. If 21 cans make 1.0 lb aluminum, how many liters of aluminum (D=2.70 g/cm3) are obtained from the cans?
1) 1.0 L 2) 2.0 L 3) 4.0 L

19. Solution 1) 1.0 L 125 cans x 1.0 lb x 454 g x 1 cm3 x 1 mL x 1 L
21 cans lb g 1 cm mL
= 1.0 L

20. Learning Check 1 2 3 25 g of aluminum 2.70 g/mL 45 g of gold 19.3 g/mL
Which of the following samples of metals will displace the greatest volume of water?
25 g of aluminum
2.70 g/mL
45 g of gold
19.3 g/mL
75 g of lead
11.3 g/mL

21. Solution 25 g of aluminum 1) 2.70 g/mL
Plan: Calculate the volume for each metal and select
the metal sample with the greatest volume.
1) 25g x 1 mL = mL aluminum g
2) 45 g x 1 mL = mL gold g
3) 75 g x 1 mL = mL lead g