1. Chapter 14: Gases
© 2015 Pearson Education, Inc.

2. Molecules that make up Earth's atmosphere don't fly off into outer space because of
their relatively high speeds.
their low densities.
Earth's gravitation.
the Sun's influence.
Answer: C) Earth's gravitation.
© 2015 Pearson Education, Inc.

3. Molecules that make up Earth's atmosphere don't fly off into outer space because of
their relatively high speeds.
their low densities.
Earth's gravitation.
the Sun's influence.
Answer: C) Earth's gravitation.
© 2015 Pearson Education, Inc.

4. Atmospheric pressure is caused by the atmosphere's
density.
weight.
temperature.
response to solar energy.
Answer: B) weight.
© 2015 Pearson Education, Inc.

5. Atmospheric pressure is caused by the atmosphere's
density.
weight.
temperature.
response to solar energy.
Answer: B) weight.
© 2015 Pearson Education, Inc.

6. The higher one goes in the atmosphere, the less the
atmospheric pressure.
density of air.
Both of these.
None of these.
Answer: C) Both of these.
© 2015 Pearson Education, Inc.

7. The higher one goes in the atmosphere, the less the
atmospheric pressure.
density of air.
Both of these.
None of these.
Answer: C) Both of these.
© 2015 Pearson Education, Inc.

8. Pulling apart a pair of evacuated Magdeburg hemispheres would be easier
at high altitudes.
at low altitudes.
beneath the surface of a lake.
None of these makes a difference.
Answer: A) at high altitudes.
© 2015 Pearson Education, Inc.

9. Pulling apart a pair of evacuated Magdeburg hemispheres would be easier
at high altitudes.
at low altitudes.
beneath the surface of a lake.
None of these makes a difference.
Explanation: Atmospheric pressure is what one pulls against, which is less at high altitudes. So the task of pulling the hemispheres apart is easier there. Beneath the surface of a lake you contend with both water pressure and atmospheric pressure, so the task there is even greater.
Answer: A) at high altitudes.
© 2015 Pearson Education, Inc.

10. The weight of a 1-square-meter column of air extending from sea level to the "top" of the atmosphere weighs about
100 N.
10,000 N.
100,000 N.
100,000,000 N.
Answer: C) 100,000 N.
© 2015 Pearson Education, Inc.

11. The weight of a 1-square-meter column of air extending from sea level to the "top" of the atmosphere weighs about
100 N.
10,000 N.
100,000 N.
100,000,000 N.
Explanation: Atmospheric pressure at sea level is roughly 105 N/m2, about 101 kPa. So over each square meter is some 101,000 N of air.
Answer: C) 100,000 N.
© 2015 Pearson Education, Inc.

12. Consider two tubes 30 km tall
Consider two tubes 30 km tall. One is filled with air and the other is partially filled with water. The weight of fluid in each will be the same when the level of water in the water tube is
10.3 m high.
76 cm high.
760 mm high.
None of these.
Answer: A) 10.3 m high.
© 2015 Pearson Education, Inc.

13. Consider two tubes 30 km tall
Consider two tubes 30 km tall. One is filled with air and the other is partially filled with water. The weight of fluid in each will be the same when the level of water in the water tube is
10.3 m high.
76 cm high.
760 mm high.
None of these.
Answer: A) 10.3 m high.
© 2015 Pearson Education, Inc.

14. A barometer can be used to measure
atmospheric pressure.
altitude.
Both of these.
None of these.
Answer: C) Both of these.
© 2015 Pearson Education, Inc.

15. A barometer can be used to measure
atmospheric pressure.
altitude.
Both of these.
None of these.
Explanation: A barometer used to measure altitude is called an aneroid barometer.
Answer: C) Both of these.
© 2015 Pearson Education, Inc.

16. A simple barometer will be tallest if it uses
mercury.
water.
gasoline (which is less dense than water).
any of these liquids, for the height would be the same at sea level.
Answer: C) gasoline (which is less dense than water).
© 2015 Pearson Education, Inc.

17. A simple barometer will be tallest if it uses
mercury.
water.
gasoline (which is less dense than water).
any of these liquids, for the height would be the same at sea level.
Explanation: Of these liquids, least-density gasoline would be tallest, an equal-diameter column of which would have to weigh as much as 76 cm of mercury or 10.3 m of water.
Answer: C) gasoline (which is less dense than water).
© 2015 Pearson Education, Inc.

18. Liquid pumps operate due to differences in
pressure.
densities of fluids.
viscosities of fluids.
energies.
Answer: A) pressure.
© 2015 Pearson Education, Inc.

19. Liquid pumps operate due to differences in
pressure.
densities of fluids.
viscosities of fluids.
energies.
Answer: A) pressure.
© 2015 Pearson Education, Inc.

20. An old-fashioned farm water pump would work best
in low-lying regions.
in mountainous regions.
if on the Moon.
on freezing cold-days.
Answer: A) in low-lying regions.
© 2015 Pearson Education, Inc.

21. An old-fashioned farm water pump would work best
in low-lying regions.
in mountainous regions.
if on the Moon.
on freezing cold-days.
Explanation: Such pumps operate by way of atmospheric pressure and are therefore best suited to low-lying regions where atmospheric pressure is greater.
Answer: A) in low-lying regions.
© 2015 Pearson Education, Inc.

22. When you squeeze an air-filled party balloon you reduce its
volume.
mass.
weight.
All of these.
Answer: A) volume.
© 2015 Pearson Education, Inc.

23. When you squeeze an air-filled party balloon you reduce its
volume.
mass.
weight.
All of these.
Answer: A) volume.
© 2015 Pearson Education, Inc.

24. When you squeeze an air-filled party balloon you increase its
volume.
mass.
weight.
density.
Answer: D) density.
© 2015 Pearson Education, Inc.

25. When you squeeze an air-filled party balloon you increase its
volume.
mass.
weight.
density.
Answer: D) density.
© 2015 Pearson Education, Inc.

26. Consider a steel tank used for storing gas
Consider a steel tank used for storing gas. If you pump enough helium into the tank, it
may float like a balloon.
will bear down with less force on the floor.
Both of these.
None of these.
Answer: D) None of these.
© 2015 Pearson Education, Inc.

27. Consider a steel tank used for storing gas
Consider a steel tank used for storing gas. If you pump enough helium into the tank, it
may float like a balloon.
will bear down with less force on the floor.
Both of these.
None of these.
Explanation: A helium-filled balloon is able to float only because its volume increases enough to displace its own weight of surrounding air. The steel tank has a fixed volume. The more helium pumped into it, the heavier it becomes.
Answer: D) None of these.
© 2015 Pearson Education, Inc.

28. A helium-filled balloon hovers in air
A helium-filled balloon hovers in air. The pressure of the atmosphere against the bottom of the balloon must be
greater than pressure against the top.
equal to the pressure on top.
less than the pressure on top.
None of these.
Answer: A) greater than pressure against the top.
© 2015 Pearson Education, Inc.

29. A helium-filled balloon hovers in air
A helium-filled balloon hovers in air. The pressure of the atmosphere against the bottom of the balloon must be
greater than pressure against the top.
equal to the pressure on top.
less than the pressure on top.
None of these.
Answer: A) greater than pressure against the top.
© 2015 Pearson Education, Inc.

30. If a hot-air balloon hovers at a fixed altitude, the net weight of the balloon must be
slightly less than the weight of displaced air.
equal to the weight of displaced air.
slightly greater than the weight of displaced air.
None of these.
Answer: B) equal to the weight of displaced air.
© 2015 Pearson Education, Inc.

31. If a hot-air balloon hovers at a fixed altitude, the net weight of the balloon must be
slightly less than the weight of displaced air.
equal to the weight of displaced air.
slightly greater than the weight of displaced air.
None of these.
Answer: B) equal to the weight of displaced air.
© 2015 Pearson Education, Inc.

32. When wind flows from a valley and over the tops of hills, the speed of the wind is greater
in the valley.
on top of the hills.
on the downside of the hills.
nowhere in particular, for air speed isn't affected by hills.
Answer: B) on top of the hills.
© 2015 Pearson Education, Inc.

33. When wind flows from a valley and over the tops of hills, the speed of the wind is greater
in the valley.
on top of the hills.
on the downside of the hills.
nowhere in particular, for air speed isn't affected by hills.
Explanation: The principle of continuity tells us that where an air path is narrower, as on top of a hill, air speed must increase.
Answer: B) on top of the hills.
© 2015 Pearson Education, Inc.

34. As water in a confined pipe speeds up, the pressure it exerts against the inner walls of the pipe
increases.
decreases.
remains constant if flow rate is constant.
None of these.
Answer: B) decreases.
© 2015 Pearson Education, Inc.

35. As water in a confined pipe speeds up, the pressure it exerts against the inner walls of the pipe
increases.
decreases.
remains constant if flow rate is constant.
None of these.
Explanation:
Straight Bernoulli!
Answer: B) decreases.
© 2015 Pearson Education, Inc.

36. Compared with the pressure within the water coming from a fire hose, the water pressure that can knock over a shed is
less.
the same.
more.
nonexistent.
Answer: C) more.
© 2015 Pearson Education, Inc.

37. Compared with the pressure within the water coming from a fire hose, the water pressure that can knock over a shed is
less.
the same.
more.
nonexistent.
Explanation: Distinguish between the pressure in the water and the pressure water can exert of something that reduces its momentum.
Answer: C) more.
© 2015 Pearson Education, Inc.

38. If air speed is greater along the top surface of a bird's wings, pressure of the moving air there is
unaffected.
less.
more.
turbulent.
Answer: B) less.
© 2015 Pearson Education, Inc.

39. If air speed is greater along the top surface of a bird's wings, pressure of the moving air there is
unaffected.
less.
more.
turbulent.
Explanation: Straight Bernoulli!
Answer: B) less.
© 2015 Pearson Education, Inc.

40. The main difference between hot gases and a plasma involves
interatomic spacing.
fluid pressure.
minute quantities of antimatter.
electrical conduction.
Answer: D) electrical conduction.
© 2015 Pearson Education, Inc.

41. The main difference between hot gases and a plasma involves
interatomic spacing.
fluid pressure.
minute quantities of antimatter.
electrical conduction.
Explanation: A property of a plasma is that it can conduct electricity.
Answer: D) electrical conduction.
© 2015 Pearson Education, Inc.