Name: ______Block: ______Date: ______

IP 614

Review: Heat, Temperature, Heat Transfer

1. In a copper wire, a temperature increase is the result of which of the following?

A. an increase in the size of the copper particles

B. a decrease in the mass of the copper particles

C. an increase in the motion of the copper particles

D. a decrease in the distance between the copper particles

2. The illustration below shows a student bending a piece of wire back and forth at a single point X. The wire’s temperature rises noticeably at point X.

Which of the following best describes the source of the temperature increase?

A. Some of the wire’s mass is transformed into heat energy as the wire is bent.

B. Some of the kinetic energy is transformed into heat as the wire is bent.

C. The bending transfers potential energy to the wire, heating it.

D. The bending causes a current that heats the wire.

3. Perfume sprayed from a bottle spreads more easily in a warm room of 25°C than in a cool room of 15°C. Which of the following correctly compares perfume molecules at 25°C to those at 15°C?

A. At 25°C, they have more mass.

B. At 25°C, they are moving faster.

C. At 25°C, they have less kinetic energy.

D. At 25°C, they are decreasing in volume.

4. The diagram below represents four empty copper containers at room temperature.

An equal amount of water at 90°C is added to each copper container. Assume there is no loss of heat to the environment. Which container will have had the greatest change in temperature when the water and the container reach equilibrium?

A. 1

B. 2

C. 3

D. 4

5. Which of the following changes occurs as a solid is heated?

A. The kinetic energy of the solid decreases.

B. The average density of the solid increases.

C. The specific heat capacity of the solid decreases.

D. The average molecular speed in the solid increases.

6.

The graph below represents changes in molecular motion in a solid plastic cylinder over time

These changes in the molecules of the plastic cylinder must be accompanied by which of the following?

A. an increase in mass

B. a decrease in volume

C. an increase in temperature

D. a decrease in heat capacity

7. Two boxes, A and B, both contain the same number of nitrogen gas molecules.

The gas molecules in box A have twice the average speed of the molecules in box B. Which of the following best describes the nitrogen gas in box A?

A. The nitrogen gas in box A has a greater mass than the nitrogen gas in box B.

B. The nitrogen gas in box A has a greater density than the nitrogen gas in box B.

C. The nitrogen gas in box A has a greater temperature than the nitrogen gas in box B.

D. The nitrogen gas in box A has a greater specific gravity than the nitrogen gas in box B.

8. A party shop delivers helium-filled balloons to homes and businesses. The owners realize from experience that on hot summer days they should inflate the balloons only three-quarters full. On cold winter days they can fully inflate the balloons. Which of the following is the best hypothesis to explain this observation?

A. The helium gas is more active in the winter season.

B. Air outside the balloons leaks into the balloons.

C. As the temperature increases, the helium in the balloons expands.

D. Outdoor air pressure in the summer is less than indoor air pressure

9. The illustration below represents an experiment in which a hot object is added to a container of water at room temperature.

The water is continuously stirred while the hot object is immersed in it. Which of the following graphs best shows the temperature changes that follow?

10. Which of the following figures correctly shows the conduction of heat within the system of metal blocks?

Open Response:

1. The illustration below shows a container of water on an electric hot plate. Point A is in the water close to the hot plate, and point B is in the water near the top of the container.

The water in the container is at room temperature before the hot plate is turned on.

  1. Describe the differences in the average motion of the water molecules at point A and at point B shortly after the hot plate is turned on.
  1. The water is heated until a thermometer placed in the center of the container reaches 100°C. Compare the average motion of the water molecules at points A and B at this temperature and explain your answer.
  1. The hot plate is then turned off. Describe the average motion of the molecules at points A and B after several hours.

Short Answers:

  1. What does it mean to say that something is hot? What does it mean to say that something is cold? Is being hot the presence or absence of something? Why do you think that?
  1. What is temperature?
  1. When you touch a piece of metal and a piece of cloth (both at room temperature), which one feels warmer? Colder? Why?
  1. Imagine we could magnify an object so much that we could see the atoms and molecules.
  2. If the object were cold, what would the atoms and molecules be doing?
  1. If the object were hot, what would the molecules be doing?
  1. What kind of energy does a molecule have if it is moving?
  1. Which contains more energy: a cup of hot water at 90 or a pot of hot water at 90?
  1. If you touch something and it feels hot, is energy being transferred?
  1. If you touch something and it feels cold, is energy being transferred?
  1. Sometimes when a friend may not feel well, you may hold your hand to her forehead to see if she has a fever. Why is this not the best way to check temperature?
  1. What happens to the volume of most materials when they are heated?

Summary of Heat Transfer: Complete the following table for heat transfer mechanism and examples

Heat Transfer / Heat flows from / Heat transmitted by… / Special Features / Examples