Review Questions: Temperature and Heat
Answers
A) heat.
B) internal energy.
C) temperature.
D) molecular kinetic energy.
2. The internal energy that is transferred from one body to another because of a temperature difference is called
A) heat.
B) potential energy.
C) temperature.
D) molecular kinetic energy.
3. Temperature is a measure of the
A) potential energy of the molecules
B) amount of heat in a body
C) average kinetic energy of molecules
D) total energy of all molecules in a body
4. A container of hydrogen gas has the same temperature as a container of denser oxygen gas. The gas atoms having the greater average kinetic energy are the
A) hydrogen,
B) oxygen,
C) both the same,
Reasoning: Since they are at the same temperature, their average kinetic energies must be the same.
5. while the gas atoms having the greater average velocity are the
A) hydrogen.
B) oxygen.
C) both the same.
Reasoning: The atoms of hydrogen have smaller mass than oxygen. Thus their speeds have to higher in order to produce the same average kinetic energies.
6. Which of the following expands most when temperature is increased?
A) iron
B) ice water
C) helium
D) all expand the same
Reasoning: Helium expands more because it is a gas.
7. Which of the following expands most when temperature is decreased?
A) iron
B) ice water
C) helium
D) all expand the same
Reasoning: Generally, when objects are cooled, they contract.However, ice-water is the exception. It will expand as it is cooled and it freezes to a larger volume.
8. The temperature difference between the ice and steam points of water is
A) 180 oC
B) 100 K
C) 100 oF
D) 273 oC
Reasoning: Water has an ice point temperature of 273 K (means Kelvin scale), and boiling point temperature of 373 K. the difference is 100 K.
9. If the temperature of 2.0 kg of water is lowered by 10 oC, the amount of heat removed would be
A) 10 kcal
B) 20 kcal
C) 20 cal
D) 10 cal
10. When a sample of air is compressed, its temperature
A) increases.
B) decreases.
C) remains unchanged.
11. One reason for this is that a molecule of gas in the compressed air collides with others that on the average are
A) moving.
B) expanding.
C) receding.
D) approaching.
12. Which has the most thermal energy?
A) an ice cube 1 cubic inch in volume
B) a tea kettle of 1 quart volume full of boiling water
C) a bathtub filled with 20 gallons of warm water
Reasoning: The thermal energy is the sum of all internal energies of an object. There are more molecules within the bath tub and the sum of their energies is more than the tea kettle.
13. The direction in which heat is conducted between two bodies depends on
A) their temperatures
B) their pressures
C) their thermal energies
D) whether they are solid, liquid, or gas
14. When water at 4oC is heated, it expands. When water at 4oC is cooled, it
A) contracts,
B) expands,
C) neither contracts nor expands,
D) ... not enough information given.
15. which follows from the fact that
A) cooling decreases the kinetic energy of H2O molecules.
B) water has its greatest density at 4oC.
C) we do not know how the water is cooled.
Reasoning: See page 300.
16. Why is steam at 100 oC is more dangerous than water at 100 oC?
A) the steam is hotter
B) the steam has more internal energy per gram
C) the steam has a higher specific heat than water
D) the steam has less viscosity
17. In the process of evaporation
A) heavier atoms are most prone to leave the liquid,
B) there is a net gain in the number of atoms in the liquid,
C) energy is absorbed by the liquid,
D) all of these,
E) none of these
18. When a molecule collides with another that is approaching with greater momentum, its rebound speed
A) stays the same,
B) increases,
C) decreases,
19. And when a molecule collides with another that is receding, its rebound speed
A) stays the same.
B) increases.
C) decreases.
20. Does it take more heat to increase the temperature of 5 grams of ice or 5 grams of water by 6 oC?
A) ice
B) water
C)..... it takes the same amount of heat in both cases
21. How many joules are equivalent of 21 calories?
A) 4.18
B) 17
C) 25
D) 88
Reasoning: One cal = 4.18 joules. Thus, 21 cal = 21 x 4.18 = 88 joules.
22. Provided that in each case heat input is the same, boiling takes place quicker
A) at sea level.
B) in a valley.
C) in the mountains.
23. This is because
A) increased pressure on the surface of a liquid lowers its boiling point.
B) decreased pressure on the surface of a liquid lowers its boiling point.
C) water always boils quickest at sea level.
24. When a solid changes to a liquid and then to a gas, energy is
A) released,
B) absorbed,
25. And when gas changes to liquid and then to solid, energy is
A) released.
B) absorbed.