MQ Heat Transfer
Answer the questions 1-5 using the picture:
Metal
Bar
32°
C
71°
C
1. In which direction is energy flowing? [Equilibrium]
a. Beaker B to the metal bar to Beaker A
b. Beaker A to the metal bar to Beaker B
c. The metal bar to Beaker A
d. Energy is not flowing
2. Based on the picture above, approximately what temperature will
equilibrium be? [Equilibrium]
a. Greater than 71°C because both beakers will receive more energy
b. Between 32°C and 71°C because A will get warmer and B will get colder
c. Less than 32°C because both beakers will lose thermal energy
d. Impossible to predict temperature because there are too many
variables
3. Which correctly describes what happens when equilibrium is reached?
[Equilibrium]
a. Beaker A will be 71°C and Beaker B will be 32°C
b. Beaker A and Beaker B will be the same temperature and the metal bar
will be colder than the two beakers
c. Beaker A, Beaker B, and the metal bar will all be the same
temperature
d. Equilibrium will never be established
4. After 20 minutes, equilibrium is established. The temperature of Beaker A
is 51°C. What must be the temperature of Beaker B? [Equilibrium]
a. 32°C
c. 47°C
b. 71°C
d. 51°C
5. Which best describes what is happening to Beaker A? [Equilibrium]
a. Beaker A transfers thermal energy to B and becomes colder
b. Beaker A transfers thermal energy to B and becomes warmer
c. Beaker A receives thermal energy from B and becomes colder
d. Beaker A receives thermal energy from B and becomes warmer
6. You put a hot pocket in the microwave. The hot pocket gets steaming hot.
When you bite the hot pocket, it burns your tongue. Which best represents
the sequence of thermal energy transfers? [Thermal.Energy]
a. Radiation, conduction
c. Convection, conduction
b. Radiation, convection
d. Conduction, radiation
7. You have a warm cup of hot chocolate. When you touch the cup, it warms
your hands. Then you hold the cup up to your face, and the steam warms
your face. Which best represents the sequence of thermal energy transfers?
[Thermal.Energy]
a.
b.
c.
d.
Conduction, radiation
Convection, conduction
Radiation, convection
Conduction, convection
8. What do molecules do when they are heated?
a. The molecules contract because they are losing energy
b. The molecules expand because they are gaining energy
c. The molecules will move slower and get closer together because they are
losing energy.
d. The molecules will move faster and spread out because they are gaining
energy.
9. What would happen to any object if the temperature decreases from 99ºF to
22ºF?
a. The object will expand because the molecules are gaining energy and
moving faster
b. The object will expand because the molecules are losing energy and
moving slower
c. The object will contract because the molecules are gaining energy and
moving faster
d. The object will contract because the molecules are losing energy and
moving slower
10.
What would happen to any object if the temperature increases from 12ºC to
56ºC?
a. The object expands because the molecules are gaining energy and moving
faster
b. The object contracts because the molecules are gaining energy and moving
slower
c. The molecules expand because they are gaining energy
d. The molecules contract because they are gaining energy
11.
A spaghetti jar has been sitting in the refrigerator for a whole day. Which
of the following best explains why the jar is difficult to open?
a. The lid has contracted because the molecules are gaining energy
b. The lid has contracted because the molecules are moving slow
c. The lid has contracted because the molecules got smaller
d. The lid has expanded because the molecules are moving faster
12. A rock is sitting outside on a hot sunny day. The sun heats the rock.
When you touch the rock, it warms your hand. What is the sequence of thermal
energy transfers?
13. You want to make mashed potatoes. The stove heats the pot of water. The
boiling water cooks your potatoes. What is the sequence of thermal energy
transfers?