Title: Density Equations
Objective: Practice density equations by
answering density story problems.
Helpful Info:
Mass units are grams (g)
Volume units are in (mL) , (cm3), (cc)
Formulas- Mass / Volume = Density
Mass /Density = Volume
Density x Volume = Mass
Date:
Make a chart like the one below and fill it out as
you do the story problems.
Practice Problems:
1. Formula___________
Equation___________
2. Formula____________
Equation___________
21. Formula___________
Equation__________
1. A block of ice has a volume of
19cm3. Its mass is 17.5 g. What is its
density?
Formula: Density = Mass /Volume
Equation: 17.5g/ 19cm3 = 0.9g/ cm3
2. Suppose 10 mL of water has a mass
of 10g. What is the density of the
water?
Formula: Density = Mass / Volume
Equation: 10g /10 Ml =1g/ mL
3. An old piece of silver jewelry has a
mass of 20g and a volume of 1.9 cm3
What is its density?
Formula: Density = Mass /Volume
Equation: 20g / 1.9cm3 = 10.5g/cm3
4. Steel has a density of 7.8 g/cm3 . If
the mass of a piece of steel is 234 g,
what is its volume?
Formula: Volume = Mass/Density
Equation: 234g / (7.8g) / cm3 = 30 cm3
5. The density of a certain type of
wood is 0.6 g/ cm3 . If the volume of a
piece of this wood is 300 cm3 , what is
its mass?
Formula: Mass = Density x Volume
Equation: 0.6g /cm3 x 300cm3 =180 g
6. A volcanic rock with a volume of
25 cm3 has a mass of 67.5 g.
What is the density of the rock?
A. 0.67 g/cm3
C. 42.5 g/cm3
B. 2.7 g/cm3
D. 92.5 g/cm3
Formula: Mass/Volume = Density
Equation: 67.5 g/25 cm3 = 2.7 g/cm3
7. A rock has a density of 8 g/cm3.
If the rock's mass is 2 g, what is the
rock's volume?
A. 0.25 cm3
C. 16 cm3
B. 4 cm3
D. 18 cm3
Formula: Volume = Mass/Density
Equation: 2 g/(8 g/cm3) = .25cm3
8. A student collected data about the
density of air. She found that .1 g of air
had a volume of 100 cm3. What is the
density of air?
A. .001 g/cm3 B. .01 g/cm3
C. .1 g/cm3
D. 1.0 g/cm3
Formula: Density = Mass/Volume
Equation: .1g / 100cm3 =.001g/cm3
9. Calculate the density of 72,000 cm3
of salt water with a mass of 73,500 g.
A. 2.4 g/cm3
C. 1.02 g/cm3
B. 2.2 g/cm3
D. 0.8 g/cm3
Formula: Density =Mass/Volume
Equation: 73,500 g/72,000 cm3 =
1.02 g/cm3
10. What is the average density of
Earth's mantle if a 1,000 cm3 sample
has a mass of 3,330 g?
A. 5.52 g/cm3
C. 0.30 g/cm3
B. 3.3 g/cm3
D. 0.37 g/cm3
Formula: Density= Mass / Volume
Equation: 3,300 g/1,000 cm3 = 3.3
g/cm3
11. If a sample of ocean water has a
density of 1.03 g/cm3 and a mass of
42,000.0 g, what is the volume of the
water?
A. 38,877 cm3
C. 42,000 cm3
B. 40,800 cm3
D. 42.235 cm3
Formula: Volume= Mass / Density
Equation: 42,000 g/(1.03 g/cm3) = 40,777 cm3
Round to 3 significant figures. 40,800 cm3
12. The Dead Sea contains the highest
concentration of salt in any body of
water on Earth. If 1230 cm3 of Dead Sea
water has a mass of 1550 g, what is the
density of the water?
A. 0.79 g/cm3
C. 1.13 g/cm3
B. 1.02 g/cm3
D. 1.26 g/cm3
Formula: Density =Mass/Volume
Equation: 1550 g/1230 cm3 = 1.26 g/cm3
13. A liquid has a density of 1g/mL.
If you have 50 mL of the liquid, what
would its mass be?
A. 25 g
C. 75 g
B. 50 g
D. 100 g
Formula: Mass = Volume x Density
Equation: 50mL x 1g/mL = 50g
14. A square chunk of plastic has a
length of 5 cm, width of 5 cm and height
of 5 cm.
It has a mass of 200 g.
What is its density?
A. .12 g/cm3 B. 1.0 g/cm3
C. 1.6 g/cm3 D. 2.3 g/cm3
Formula: Density= Mass / Volume
Equation: 200g /(5x5x5) =1.6 g/cm3
15. Water has a density of 1 g/mL.
What density might a typical rock
be?
A. .005 g/cm3 B. .5 g/cm3
C. 5 g/cm3
D. 50 g/cm3
Hint: Rocks are more dense than
water. The answer would have to
be more than the density of water
which is 1g/mL.
Answer: Letter ‘C’ with 5 g/cm3 is the next
most dense after water with letter ‘D’
extremely dense, not a good choice.
*16. A rock dropped in a graduated
cylinder raises the level of water from 20
to 35 mL. The rock has a mass of 45 g.
What is the density of the rock?
A. 1.3 g/cm3 B. 2.3 g/cm3
C. 3.0 g/mL D. 4.5 g/cm3
Formula: Density = Mass/Volume
displacement from 20mL to 35ml is = 15mL
Equation: 45g/ 15mL = 3.0g/mL
*17. Water has a density of
1 gram/milliliter. There are four rocks
that all have the same volume of
5 cubic centimeters. The mass for each
of these rocks is given below. Which of
the four rocks will float when placed in
water?
A. 15 grams B. 10 grams
C. 6 grams D. 4 grams
Formula: M/V=D
X/5= (<1)
Answer : A. 15/5=3
B. 10/5=2
C. 6/5=1.2
D. 4/5=0.8 *
*18. A liquid is found to have a
volume of 75 mL in a graduate.
When placed on a balance, the
liquid and graduated cylinder have a
mass of 125 g. The empty graduated
cylinder has a mass of 50 g.
What is the density of the liquid?
A. .1 g/mL
C. 2.2 g/mL
B. 1 g/mL
D. 22 g/mL
Hint: Density =M / V
125g (cylinder w/ liquid) subtract 50g (cylinder
alone)=75g
Equation: 75 /75 mL =1g/mL
*19. Water has a density of 1.0
g/mL. Which of the following
substances would float in water?
A. a substance with a volume of 418.2
mL and a mass of 423.23 grams
B. a substance with a mass of 534.23
grams and a volume of 522.3 mL
C. a substance with a volume of 3.35 mL
and a mass of 22.64 grams
D. a substance with a mass of 1.33
grams and a volume of 1.38 mL
Formula: Divide Mass by volume for
each. The answer must be less than
1.0g/mL to float, the density of water.
Equation: D
1.33 g/1.38 mL = 0.96 g/mL. This is less dense
than water, so it will float.