1. Mrs. O’Rourke September, 2006
Density Review
Mrs. O’Rourke
September, 2006

2. Question #1 Density of different items:
Gasoline—0.7 g/ml
Water—1.0 g/ml
Aluminum—2.7 g/cm3
Iron—7.3 g/cm3
Silver—10.5 g/cm3
Lead—11.3 g/cm3
Gold 19.3 g/cm3
Mercury, a metallic liquid element, has a density of 11.3 g/ml. If you placed the metals listed to the left in mercury, draw and label a graduated cylinder that shows what would happen?

3. Question #1 Answer
The column should show that all would float, except gold. The lead could be shown as suspended in the mercury.

4. Question #2 Which of the following would float on pure water?
A. A substance with a mass of 1.33 g and a volume of 1.38 mL.
B. A substance with a volume of 3.35 mL and a mass of g.
C. A substance with a volume of mL and a mass of g.
D. A substance with a mass of g and a volume of mL.

5. Question #2 Answer
Both A and C would float on water.

6. Question #3 Mass is equal to ????, while volume is equal to ?????
A. Density/volume; mass/density
B. Density/volume; mass X density
C. Density X volume; mass X density
D. Density X volume; mass/density

7. Question #3 Answer
D; mass is equal to density X volume; volume is equal to mass/density.

8. Question #4
Alicia has a pure gold coin that has a mass of g. Gold has a density of 19.3 g/cm3. What is the volume of the coin?

9. Question #4 Answer
6.23 cm3

10. Question #5
When water freezes it expands it’s volume by 7%. What is the density of ice?
0.30 g/mL
1.7 g/mL
1.07 g/mL
0.93 g/mL

11. Question #5 Answer
0.93 g/mL

12. Question #6 Density of different items:
Gasoline—0.7 g/ml
Water—1.0 g/ml
Aluminum—2.7 g/cm3
Iron—7.3 g/cm3
Silver—10.5 g/cm3
Lead—11.3 g/cm3
Gold 19.3 g/cm3
Keshia has 3.0 cm3 of gold, lead, silver, iron, and aluminum. Which of the following is false?
A. All of the samples have different masses
B. The aluminum has the smallest mass
C. The gold has the greatest volume
D. The silver has a mass of 31.5 grams.

13. Question #6 Answer
C; They all have the same volume: 3cm3. Gold would have the most mass.

14. Question #7
Jose has a 10 cm3 sample of silver while Alicia has a 30 cm3 of silver. Which of the following is false?
A. Alicia’s sample has 3 times the volume of Jose’s sample.
B. Alicia’s sample has 3 times the density of Jose’s sample.
C. Alicia’s sample has 3 times the mass of Jose’s sample.
D. Jose’s sample has 1/3 the mass of Alicia’s.

15. Question #7 Answer
B; density of an object does not change when you ONLY cut it into smaller pieces. You must heat it, cool it, add a solute to the solvent, or increase or decrease the pressure on the substance to change the density.

16. Question #8 If you heat a sample of gas, the density of the gas:
A. Remains the same
B. Decreases
C. Increases
D. Impossible to tell

17. Question #8 Answer
B; when you heat a gas, the volume expands due to the increase of the speed of the molecules. The mass would stay the same, volume would increase, so density would decrease.

18. Question #9
An object has these dimensions: The length is 5 cm, the width is 2 cm, and the height is 10 cm. What is the volume?
If the object has a mass of 65 grams, what is its density?

19. Question #9 Answer
100 cm3; 5 cm X 2 cm X 10 cm
.65 g/cm3; 65g/100cm3

20. Question #10
Your teacher gives you a little block of metal which is exactly 1 centimeter square. It is small, but has a mass of 4.5 grams. What is its density?

21. Question #10 Answer
4.5 g/cm3; 4.5g/1cm3

22. Question #11
A piece of metal has a mass of 3 grams and has a density of 2.70 g/cm3. What is its volume?

23. Question #11 Answer
1.11 cm3

24. Question #12
A piece of foil has a volume of 0.90 cubic centimeters. If the foil is 30 centimeters by 18 centimeters, what is its height.

25. Question #12 Answer cm
30 X 18 X = .90

26. Question #13
A piece of aluminum foil has a mass of 1.60 grams. It is 30 cm by 10 cm. If we assume that the density of the foil is 2.70 g/cm3, what is the thickness of the foil?

27. Question #13 Answer
or .002

28. Question #14
A furniture maker wants to determine if two pieces of wood are of the same type. He knows that the two woods have different densities. The first piece is 30 X 14 X 2.5 cm and has a mass of 350 grams. The second piece is 15 X15 X 10 cm and has a mass of 900 grams. Are they different types of wood?

29. Question #14 Answer
yes; the density of the first piece is .33 g/cm3, the density of the second piece is 1.2 g/cm3.

30. Question #15
When salt is added to water the density increases. Marine biologists use this characteristic to measure the salinity in sea water. A biologist knows that the density of the water must be between 1.05 and 1.08 g/cm3. She finds that 80 mL has a mass of 83.2 grams. Is this water within the limits?

31. Question #15 Answer
No, It is only 1.04 g/mL, so the salinity level is too low.

32. Question #16
28.5g of iron shot is added to a graduated cylinder containing mL of water. The water level rises to the mL mark. What is the density of iron?

33. Question #16 Answer
or 7.92 g/cm3

34. Question #17
A piece of wood that measures 3 X 6 X 4 cm has a mass of 80 grams. What is the density of the wood?
Would it float in water?

35. Question #17 Answer
1.11 g/cm3
No, it will not float. It is more dense than water.

36. Question #18
A cup of gold colored beads was measured to have a mass of 425 grams. By water displacement the volume of the beads was calculated to be 48.0 cm3. Given the following densities, identify the metal:
Gold: g/cm3
Copper: g/cm3
Bronze: g/cm3

37. Question #18 Answer
copper

38. Question #19
Lynn threw a plastic ball into his pool for his dog to fetch. The mass of the ball was 125 grams. What must the volume be to have a density of 0.50 g/cm3. (He wants it to float, of course!)
After throwing the ball into the pool, it sprang a leak and began to fill up with water. How many mL of water can the ball absorb before the ball sinks?

39. Question #19 Answer The ball must have a volume of 250 cm3.
When the ball has absorbed 126 mL it will sink

40. Question #20
What is the mass of a cylinder of lead that is 2.50 cm in diameter and 5.50 cm long? The density is 11.4 g/cm3.

41. Question #20 Answer
or g

42. Question #21
An ice cube measuring 5.80 cm by 5.80 cm has a density of g/mL. What is the mass of the ice cube?

43. Question #21 Answer
or g

44. Question #22
Gasoline is non-polar liquid that will float on water grams of gasoline is spilled into a puddle of water. If the density of gasoline is g/mL, what volume of gasoline was spilled?

45. Question #22 Answer mL

46. Question #23
A little aluminum boat (mass of 14.50g) has a volume of cm3. The boat is placed in a small bucket of water and carefully filled with pennies. If each penny has a mass of 2.50g, how many pennies can be added to the boat before it sinks?

47. Question #23 Answer 175 pennies
Mass to volume must be greater than mL would need to have just over 450 g to sink. We have 14.5 g – 14.5 = 435.5g
435.5/2.5 (gram per penny) = So you must add 175 pennies to sink your boat.

48. Question #24
A sample of the mineral pyrite has a mass of 150g and a volume of 30 cm3. What is the density of pyrite?
If I cut my sample of pyrite in half; what would its new mass, volume, and density be?

49. Question #24 Answer The density of pyrite would be 5 g/cm3.
If the sample were cut in half, the mass and volume would as be cut in half; however, the density would not change. New mass: 75g. New volume: 15 cm3.