Title: Density Equations Date: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

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 /VolumeEquation: 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 / VolumeEquation: 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/DensityEquation: 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 VolumeEquation: 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 B. 2.7 g/cm3

C. 42.5 g/cm3 D. 92.5 g/cm3

Formula: Mass/Volume = DensityEquation: 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 B. 4 cm3

C. 16 cm3 D. 18 cm3

Formula: Volume = Mass/DensityEquation: 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/VolumeEquation: .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 B. 2.2 g/cm3

C. 1.02 g/cm3 D. 0.8 g/cm3

Formula: Density =Mass/VolumeEquation: 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 B. 3.3 g/cm3

C. 0.30 g/cm3 D. 0.37 g/cm3

Formula: Density= Mass / VolumeEquation: 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 B. 40,800 cm3

C. 42,000 cm3 D. 42.235 cm3

Formula: Volume= Mass / DensityEquation: 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 B. 1.02 g/cm3

C. 1.13 g/cm3 D. 1.26 g/cm3

Formula: Density =Mass/VolumeEquation: 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 B. 50 g C. 75 g D. 100 g

Formula: Mass = Volume x DensityEquation: 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 / VolumeEquation: 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/Volumedisplacement from 20mL to 35ml is = 15mLEquation: 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=3B. 10/5=2C. 6/5=1.2D. 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 B. 1 g/mL C. 2.2 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: D1.33 g/1.38 mL = 0.96 g/mL. This is less dense than water, so it will float.