# Title: Density Equations Date:

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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: Formula___________ Equation___________ 2. Formula____________ 21. Formula___________ Equation__________

1. A block of ice has a volume of 19cm3. Its mass is 17. 5 g
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
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

Formula: Density = Mass /Volume Equation: 20g / 1.9cm3 = 10.5g/cm3
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
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
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

Formula: Mass/Volume = Density Equation: 67.5 g/25 cm3 = 2.7 g/cm3
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 g/cm B. 2.7 g/cm3 C g/cm D g/cm3 Formula: Mass/Volume = Density Equation: 67.5 g/25 cm3 = 2.7 g/cm3

Formula: Volume = Mass/Density Equation: 2 g/(8 g/cm3) = .25cm3
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 cm B. 4 cm3 C. 16 cm 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
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

Formula: Density =Mass/Volume
9. Calculate the density of 72,000 cm3 of salt water with a mass of 73,500 g. A. 2.4 g/cm B. 2.2 g/cm3 C g/cm D. 0.8 g/cm3 Formula: Density =Mass/Volume Equation: 73,500 g/72,000 cm3 = 1.02 g/cm3

Formula: Density= Mass / Volume
10. What is the average density of Earth's mantle if a 1,000 cm3 sample has a mass of 3,330 g? A g/cm B. 3.3 g/cm3 C g/cm D 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
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 cm B. 40,800 cm3 C. 42,000 cm D cm3 Formula: Volume= Mass / Density Equation: 42,000 g/(1.03 g/cm3) = 40,777 cm3 Round to 3 significant figures. 40,800 cm3

Formula: Density =Mass/Volume Equation: 1550 g/1230 cm3 = 1.26 g/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 g/cm B g/cm3 C g/cm D g/cm3 Formula: Density =Mass/Volume Equation: 1550 g/1230 cm3 = 1.26 g/cm3

Formula: Mass = Volume x Density Equation: 50mL x 1g/mL = 50g
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 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
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
*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= D. 4/5=0.8 *

18. A liquid is found to have a volume of 75 mL in a graduate
*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
*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 mL and a mass of grams B. a substance with a mass of grams and a volume of mL C. a substance with a volume of 3.35 mL and a mass of 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.