5th Six Weeks Review

Roger heats a brass metal cube (specific heat = 375 J/kg·°C) to 70.0°C and places the cube into an insulated container of water (specific heat = 4182 J/kg·°C). He observes that the water temperature increases from 10.0°C to a final temperature of 18.0°C. What is the final temperature of the metal cube?

• 10.0°C

• 18.0°C

• 35.0°C

• 62.0°C

Which change will occur in a system with increasing entropy?

• Thermal energy will increase.

• Mechanical energy will increase.

• Elastic potential energy will decrease.

• Gravitational potential energy will decrease.

Which statement describes a solid compared to the other states of matter?

• The particles have the least molecular kinetic energy and lowest system disorder.

• The particles have the least molecular kinetic energy and greatest system disorder.

• The particles have the greatest molecular kinetic energy and the lowest system disorder.

• The particles have the greatest molecular kinetic energy and the greatest system disorder.

Air conditioners contain refrigerant, a substance that circulates through pipes of the

system. The refrigerant transfers large amounts of heat from the air inside a room to

the air outside by using a continuous cycle of evaporation and condensation. Which of

the following best explains why evaporation and condensation play an important role

in air conditioning?

• Substances release heat energy when they evaporate and absorb heat energy when they condense.

• Substances absorb heat energy when they evaporate and release heat energy when they condense.

• Substances release heat energy when they evaporate and when they condense.

• Substances absorb heat energy when they evaporate and when they condense.

Entropy is a measure of the amount of disorder in a system. The concept of entropy can be applied to an ice cube melting. Which statement best describes the puddle of water?

• It is at minimum entropy and minimum order.

• It is at maximum entropy and minimum order.

• It is at minimum entropy and maximum order.

• It is at maximum entropy and maximum order.

When water evaporates from Earth’s surface into the atmosphere, its molecules enter

the gas state. What subsequent change causes gas molecules to condense into the small water droplets that form clouds?

• Mass is reduced.

• Volume is increased.

• Temperature is reduced.

• Pressure is increased.

A diagram of the water cycle is shown.

Which occurs as water moves from evaporation to condensation in the water cycle?

• Energy is consumed.

• Some water disappears.

• Mass is converted to energy.

• Energy is released by water molecules.

When Dennis operates his lawnmower, he notices the engine makes a lot of noise. He also notices that the engine gets very hot. Which best describes the heat and noise generated from the lawnmower?

• a change in phase

• thermal expansion

• an increase in entropy

• mechanical advantage

Computers have devices called heat sinks designed to lower the temperature of a computer by scattering produced heat into the surrounding area. Which type of energy is kept away from a computer by a heat sink?

• electrical

• chemical

• thermal

• nuclear

When heat flows from a hot spot to a cooler spot, entropy increases. When heat is forced to flow from a cool spot to a warmer spot, entropy decreases. Marta is looking for something in her house that causes a decrease in entropy. Which of these should she choose?

• an ice cube melting

• the refrigerator

• an egg frying

• the toaster