CHAPTER 2: THE FIRST LAW OF THERMODYNAMICS

1. What does the first law of thermodynamics state?

• a) Energy cannot be destroyed, only converted.

• b) Work and heat are unrelated to energy.

• c) Energy can be created from nothing.

• d) Temperature is constant during all processes.

2. Which of the following is NOT a mode of heat transfer?

• a) Conduction

• b) Convection

• c) Radiation

• d) Compression

3. What is the main internal energy change when water boils?

• a) Increase in potential energy

• b) Increase in kinetic energy

• c) Loss of energy as heat

• d) No change in internal energy

4. What happens to water in a rigid, sealed container when it is heated?

• a) The pressure increases.

• b) The temperature decreases.

• c) The water boils at 100°C.

• d) The volume of the container expands.

5. Which of the following equations represents the first law of thermodynamics?

• Q=mcΔT

• ΔU=Q−W

• P=F/A

• W=PΔV

6. Why does water boil at a higher temperature in a pressure cooker?

• a) Increased pressure raises the boiling point of water.

• b) The heat source is more powerful.

• c) Water molecules are lighter under pressure.

• d) The container allows heat to escape.

7. Which of the following best describes internal energy?

• a) The energy stored due to the system's motion.

• b) The sum of potential and kinetic energies at the molecular level.

• c) The energy transferred by conduction and convection only.

• d) The energy stored in a system due to chemical reactions.

8. When does a system perform work in a thermodynamic process?

• a) When heat is transferred.

• b) When there is a change in volume.

• c) When no energy transfer occurs.

• d) When the pressure remains constant.

9. In an open system, water boils and some of it turns into vapor. Why does the mass of the liquid water decrease over time?

• a) Heat is removed from the system.

• b) Water molecules escape as vapor.

• c) Volume decreases during the process.

• d) Potential energy of water decreases.

10. A copper block is rubbed against sandpaper. Which form of energy transfer is primarily responsible for the rise in its temperature?

• a) Convection

• b) Work

• c) Heat transfer

• d) Radiation