Unit 7 Review

A student is cooking an egg in a pan on a stovetop. What is the main method of heat transfer between the pan and the egg?

• conduction

• convection

• entropy

• radiation

NASA developed a reflective foil barrier to help shield spacecraft from heat transfer in space. These reflective barriers are now used in homes to prevent heat transfer by the same method.

What method of heat transfer is being prevented by the reflective barrier?

• conduction

• convection

• entropy

• radiation

A student is investigating the best method for heating marshmallows using an open flame. The student quickly discovers that placing the marshmallow over the flame is more effective than heating the marshmallow on the side of the flame. According to the information above, what type of heat transfer is present when the marshmallow is above the fire that is not present when the marshmallow is on the side of the fire? What method of heat transfer is being prevented by the reflective barrier?

• conduction

• convection

• entropy

• radiation

A tray filled with ice is removed from the freezer. After a short period of time, the ice begins to melt.

As the ice melts, it ―

• decreases in specific heat capacity

• decreases in temperature

• increases in entropy

• increases in temperature

A student is at home on a hot summer day when the air conditioning stops working. The student opens the door to the refrigerator and seals off the kitchen from the rest of the house.

Which best describes the change in temperature and entropy of the air molecules in the kitchen?

• Temperature and entropy decrease

• Temperature decreases and entropy increases

• Temperature increases and entropy decreases

• Temperature and entropy increase

A student is investigating the relationship between pressure, temperature, and entropy. A student manages to obtain a sample of ice, water, and water vapor that all coexist at the same temperature called the triple point.

Which will have the greatest entropy at the triple point?

• solid

• liquid

• gas

• The entropy will be equal in all states.

In the lab, a student places a 5 kg container of water on a hot plate. The heating of the water is constant. The student records the temperature and graphs it as a function of time on the graph below.

Which point on the above graph has the lowest entropy level?

• A

• B

• D

• E

In the lab, a student places a 5 kg container of water on a hot plate. The heating of the water is constant. The student records the temperature and graphs it as a function of time on the graph below.

According to the graph above, which change will likely require the most heat?

• A → B

• B → C

• C → D

• D → E

A student that just received their driver’s license decides to buy a new car. He remembers from physics class that heat engines have a thermal efficiency that can be calculated. He asks the car dealer for a car that has a high thermal efficiency rating. The car dealer says he has a car that is 100% efficient.

Which law of thermodynamics best describes why the car cannot be 100% efficient.

• The zeroth law of thermodynamics

• The first law of thermodynamics

• The second law of thermodynamics

• The third law of thermodynamics

A geothermal system works to supply heat from deep underground in order to heat or cool a structure. These systems take advantage of the relatively constant temperature underground.

Students were asked to predict the heat flow in the summer and winter. Their predictions were recorded.

According to the information given, which student's prediction best describes the movement of heat in both the summer and winter?

• Andrea

• Betty

• Carlos

• Darius