MCAS Heat and Heat Transfer 1

1.

1 point

A container of water with an initial temperature of 90°C is placed in a room where the temperature is 20°C. Which of the following statements describes what happens to the water over the next several hours?

The thermal energy of the water decreases, and its temperature decreases to 5°C.

The thermal energy of the water decreases, and its temperature decreases to 20°C.

The thermal energy of the water remains constant, and its temperature decreases to 55°C.

The thermal energy of the water remains constant, and its temperature decreases to 70°C.

2.

1 point

Which of the following statements describes an advantage of using a wooden spoon instead of a metal spoon to stir a pot of hot soup?

A wooden spoon radiates heat faster than a metal spoon.

A wooden spoon has a lower specific heat than a metal spoon.

A wooden spoon does not conduct heat to its handle as quickly as a metal spoon.

A wooden spoon lowers the boiling point of the soup, but a metal spoon does not.

3.

1 point

The graph below shows the temperature of a sample of water as it is heated at a constant rate.

Which of the following conclusions is best supported by the information in the graph?

The water boils between points X and Y and condenses between points Y and Z.

The average kinetic energy of the water molecules increases between points X and Y and stays the same between points Y and Z.

The water evaporates between points X and Y and the average kinetic energy of the water molecules increases between points Y and Z.

The average kinetic energy of the water molecules remains the same between points X and Y and the water boils between points Y and Z.

4.

1 point

Sunlight heats a dark rock. A snake then moves onto the rock in order to increase its body temperature.
Which of the following sequences represents how heat energy is transferred from the Sun to the rock to the snake?

radiation then conduction

radiation then convection

conduction then radiation

convection then radiation

5.

1 point

Thermal energy is added to a sample of 15°C water. Which of the following quantities must increase?

the water’s mass

the water’s salinity

the water’s specific heat

the water’s temperature

6.

1 point

A student slowly heats a beaker of a liquid on a hot plate. The liquid has a boiling point of 78°C. The student makes the graph shown below from the data she records as the liquid is heating.

Which of the following statements best describes what happens to the molecules of liquid between 5 and 10 minutes of heating?

The mass of the molecules increases.

The molecules undergo a chemical change.

The molecules absorb energy to change phase.

The average kinetic energy of the molecules decreases.

7.

1 point

Which of the following statements best explains how heat flows by conduction?

A large mass of air begins to move faster.

Energy is transferred by electromagnetic waves.

Energy is transferred from molecule to molecule.

A large mass of warm air rises, replacing the cooler air above.

8.

1 point

Which of the following substances has the lowest average molecular kinetic energy?

nitrogen at 75°C

quartz at 25°C

steel at 50°C

water at 10°C

9.

1 point

Calorimeters are instruments used to measure heat. The diagrams below show a calorimeter before a metal sample is added and after the sample is added.

Which of the following statements describes the flow of heat energy after the metal sample is added?

Heat energy flows from the stirrer to the thermometer.

Heat energy flows from the water to the metal sample.

Heat energy flows from the metal sample to the water.

Heat energy flows from the insulation to the thermometer.

10.

1 point

What method of heat transfer allows the Sun’s heat energy to reach Earth through the vacuum of space?

condensation

conduction

convection

radiation

11.

1 point

An iron bar is placed in a flame, as shown below, and is heated until the end glows.

The other end of the iron bar soon becomes hot, too. Which of the following statements best describes what happens?

A convective flow of energy is set up inside the iron bar.

Energy is conducted from atom to atom along the length of the iron bar.

Radiation moves through the iron bar and is absorbed by the end not in the flame.

Air heated by the flame radiates down the iron bar and heats the end not in the flame.

12.

1 point

A cup of tea with a temperature of 80°C is placed on a table in a 20°C room. What happens to the thermal energy and molecular motion of the tea when it is left on the table?

The thermal energy increases and the molecules move faster.

The thermal energy decreases and the molecules move faster.

The thermal energy increases and the molecules move more slowly.

The thermal energy decreases and the molecules move more slowly.

13.

1 point

A small body of water contains 2,000 kg of water. The specific heat of water is 4,180 J/kg • °C.
If the temperature of the water changes from 25°C to 20°C, approximately how much heat moves from the water to the surroundings?

8,400,000 J

42,000,000 J

168,000,000 J

210,000,000 J

14.

1 point

A sealed glass jar containing 200 mL of cold water is lowered into a large beaker containing 200 mL of hot water. Which of the following graphs shows how the temperature of each water sample will most likely change over time?

15.

1 point

Popcorn is made by heating corn kernels. Different methods may be used to heat the kernels.
Which of the following methods uses radiation as the primary means of transferring energy to the corn kernels?

heating corn kernels in a hot air popper

heating corn kernels in a microwave oven

heating corn kernels in a foil pan on a hot plate

heating corn kernels in oil in a pot on an electric stove