Physical Science II
Heat Review
Name ____________________
Period____________________
Conceptual Questions
1. What two things help determine how much the temperature of an object will change?
The mass of the material and the specific heat capacity of the material.
2. Explain the kinetic theory of matter?
The kinetic theory of matter explains that all materials in the universe are made up of
microscopic particles that are constantly in motion.
3. How does the kinetic theory of matter help us understand temperature?
The faster particles in an object move the more energy the object has and the higher its
temperature will be.
4. What generally happens to a material as you remove heat from it?
The material will contract (shrink). Also, its temperature will decrease.
5. Which way does heat always transfer?
Heat always flows from higher temperature objects to lower temperature objects.
6. What does it mean if a group of objects are in thermal equilibrium?
The objects would all have the same temperature.
7. What happens to water if you cool it from 4°C to 0°C?
As water cools in this temperature range the liquid will actually expand and become less dense.
8. What is the difference between internal energy and temperature?
Internal energy is the total energy an object has, while temperature is a measurement of the
average kinetic energy of an object. Therefore, it is possible for two objects to have different
internal energies, but have the same temperature.
9. If you place a hot metal sample into a cup of cool water, the temperature of the metal drops
greatly, but the temperature of the water only increases slightly. What causes this to occur?
The metal has a lower specific heat capacity than the water, so it takes less energy to change the
temperature of the metal than to change the temperature of the water.
10. Which material will have a greater internal energy?
a. A 2kg mass of copper at 20°C.
b. A 2kg mass of copper at 25°C.
Material (b) will have the greater internal energy, because both have the same mass, but
the temperature of (b) is higher. Higher temperature means the particles move faster and
have more energy.
11. Which material will have a greater internal energy?
a. A 1kg block of ice at -10°C.
b. A 0.5kg block of ice at -10°C.
Material (a) will have more internal energy because the temperature is the same, but the
mass of (a) is larger. More mass means more particles and more energy.
12. Why does the water of a lake start freezing at the surface?
The water at the top of the lake is colder and less dense than the water near the bottom. Thus
the water at the top starts to freeze first.
13. Theoretically, what happens when the temperature of a substance reaches zero Kelvin?
At zero Kelvin, the temperature of a material is at its lowest and theoretically, all molecular
activity would stop completely.
14. What is the boiling point of water on the Celsius scale and also on the Fahrenheit scale?
100°C and 212°F
15. What is the freezing point of water on the Celsius scale and also on the Fahrenheit scale?
0°C and 32°F
16. What type of energy flows between two objects at different temperatures?
Heat Energy
17. Why does the deck of a pool become very hot in the summer sun, but the water remains relatively
cool?
The pool deck is made from materials with a low specific heat capacity, so its takes less energy
to change the temperature of the pool deck.
18. What does the specific heat of a material measure?
Specific heat measures how much energy it takes to change the temperature of 1kg of a
substance by 1°C. The lower the specific heat, the easier it is to change the temperature of a
substance.
19. List two examples of heat being transferred by radiation.
The warming of the Earth by the sun’s rays. The heating of food using a microwave oven.
20. List two examples of heat being transferred by conduction.
When holding a cold drinking glass, your hand will transfer heat into that glass. When you place
a spoon into a pot of hot soup, the soup will transfer heat into the spoon.
21. List two examples of heat being transferred by convection.
The mixing of warm air and cold air when you turn a heater on in a room. When you dump a
warm bucket of water into a bathtub filled with cold water, the warm water will slowly mix with
the cold water.
22. What is the name given to the study of heat and heat energy?
Thermodynamics
23. If you continue to add heat to a metal rod, what will happen to the rod (besides increasing its
temperature).
The rod will expand (its length will increase).
24. Which temperature scale is used by most of the world and serves as the basic scale of the
International System of Units (SI Units)?
The Celsius scale.
25. Which temperature scale is used solely by the scientific community?
The Kelvin Scale
Problem Solving
1. Convert the temperature of 65°F to temperatures measured in degrees Celsius and in Kelvin.
𝟓
𝟓
°𝑪 = 𝟗 (°𝑭 − 𝟑𝟐)
°𝑪 = 𝟗 (𝟔𝟓 − 𝟑𝟐)
°𝑪 = 𝟏𝟖. 𝟑𝟑°
𝑲 = °𝑪 + 𝟐𝟕𝟑
𝑲 = 𝟏𝟖. 𝟑𝟑° + 𝟐𝟕𝟑
𝑲 = 𝟐𝟗𝟏. 𝟑𝟑
2. Convert the temperature of 300K to temperatures measured in degrees Celsius and Fahrenheit.
°𝑪 = 𝑲 − 𝟐𝟕𝟑
𝟗
°𝑭 = 𝟓 𝑪 + 𝟑𝟐
°𝑪 = 𝟑𝟎𝟎 − 𝟐𝟕𝟑
𝟗
°𝑭 = 𝟓 (−𝟐𝟕) + 𝟑𝟐
°𝑪 = −𝟐𝟕°
°𝑭 = −𝟏𝟔. 𝟔
3. Convert the temperature of 70°C to temperatures measured in Kelvin and degrees Fahrenheit.
𝑲 = °𝑪 + 𝟐𝟕𝟑
𝟗
𝟓
°𝑭 = 𝑪 + 𝟑𝟐
𝑲 = 𝟕𝟎° + 𝟐𝟕𝟑
𝑲 = 𝟑𝟒𝟑
𝟗
𝟓
°𝑭 = (𝟕𝟎) + 𝟑𝟐
°𝑭 = 𝟏𝟓𝟖°
4. How much heat is absorbed by 0.050kg of silver when it is heated from 10°C to 80°C?
𝑸 = 𝒎𝑪∆𝑻
𝑱
𝑸 = (𝟎. 𝟎𝟓𝟎𝒌𝒈)(𝟐𝟑𝟒 𝒌𝒈°𝑪)(𝟖𝟎°𝑪 − 𝟏𝟎°𝑪)
𝑸 = 𝟖𝟏𝟗𝑱
5. What is the specific heat of 0.040kg of an unknown substance that needs 837.2J of heat to
change its temperature from 5°C to 10°C? Also what is the identity of this unknown material?
𝑸 = 𝒎𝑪∆𝑻
𝟖𝟑𝟕. 𝟐𝑱 = (𝟎. 𝟎𝟒𝟎𝒌𝒈)(𝑪)(𝟏𝟎°𝑪 − 𝟓°𝑪)
𝑱
𝑪 = 𝟒𝟏𝟖𝟔 𝒌𝒈°𝑪
6. What is the temperature change of 0.025kg of gold if 51.6J of heat are added to it?
Water
𝑱
𝑸 = 𝒎𝑪∆𝑻
𝟓𝟏. 𝟔𝑱 = (𝟎. 𝟎𝟐𝟓𝒌𝒈)(𝟏𝟐𝟗 𝒌𝒈°𝑪)(∆𝑻)
∆𝑻 = 𝟏𝟔°𝑪
7. If 27,090J of heat are removed from a block of copper in order to decrease its temperature by
35°C, what mass of copper was being cooled?
𝑸 = 𝒎𝑪∆𝑻
−𝟐𝟕, 𝟎𝟗𝟎𝑱 = (𝒎)(𝟑𝟖𝟕
𝑱
)(−𝟑𝟓°𝑪)
𝒌𝒈°𝑪
𝒎 = 𝟐𝒌𝒈
8. A calorimeter containing 0.300kg of water is initially at a temperature of 20°C. An unknown
metal sample with a mass of 0.080kg, initially at a temperature of 105.5°C is placed into the
calorimeter containing the water. After a few seconds, the calorimeter water and the metal
reach a final temperature of 22.0°C.
a. How much heat is gained by the water?
𝑸 = 𝒎𝑪∆𝑻
𝑱
𝑸 = (𝟎. 𝟑𝟎𝟎𝒌𝒈)(𝟒𝟏𝟖𝟔 𝒌𝒈°𝑪)(𝟐𝟐°𝑪 − 𝟐𝟎°𝑪)
𝑸 = 𝟐𝟓𝟏𝟏. 𝟔𝑱
b. Assume that the heat gained by the water is the same as the heat lost by the metal. What is
the specific heat of the metal sample?
𝑸 = 𝒎𝑪∆𝑻
−𝟐𝟓𝟏𝟏. 𝟔𝑱 = (𝟎. 𝟎𝟖𝟎𝒌𝒈)(𝑪)(𝟐𝟐°𝑪 − 𝟏𝟎𝟓. 𝟓°𝑪)
𝑱
𝑪 = 𝟑𝟕𝟓. 𝟗𝟖 𝒌𝒈°𝑪
c. What is the identity of the metal sample?
Brass
9. A calorimeter containing 0.400kg of water is initially at a temperature of 15°C. An unknown
metal sample with a mass of 0.100kg, initially at a temperature of 126.6°C is placed into the
calorimeter containing the water. After a few seconds, the calorimeter water and the metal
reach a final temperature of 20.0°C.
a. What is the identity of the metal sample?
Find the heat gained by the water.
𝑸 = 𝒎𝑪∆𝑻
𝑸 = (𝟎. 𝟒𝟎𝟎𝒌𝒈)(𝟒𝟏𝟖𝟔
𝑱
)(𝟐𝟎°𝑪 − 𝟏𝟓°𝑪)
𝒌𝒈°𝑪
𝑸 = 𝟖𝟑𝟕𝟐𝑱
Find specific heat of metal.
𝑸 = 𝒎𝑪∆𝑻
−𝟖𝟑𝟕𝟐𝑱 = (𝟎. 𝟏𝟎𝟎𝒌𝒈)(𝑪)(𝟐𝟎°𝑪 − 𝟏𝟐𝟔. 𝟔°𝑪)
Identify the material.
Granite.
𝑱
𝑪 = 𝟕𝟖𝟓. 𝟒 𝒌𝒈°𝑪