11. The heat of reaction is also known as:

• A) Activation energy
• B) Enthalpy change
• C) Free energy change
• D) Work done
• Answer: B

12. The heat of reaction is measured in:

• A) Joules
• B) Calories
• C) Kelvin
• D) Both A and B
• Answer: D

13. In an exothermic reaction, the heat of reaction is:

• A) Positive
• B) Negative
• C) Zero
• D) Infinite
• Answer: B

14. Which of the following reactions is typically endothermic?

• A) Combustion
• B) Photosynthesis
• C) Neutralization
• D) Respiration
• Answer: B

15. The heat of reaction is the difference between the enthalpy of:

• A) Reactants and products
• B) Products and reactants
• C) Catalyst and reactants
• D) Reactants and temperature
• Answer: B

16. Which of the following is true for an endothermic reaction?

• A) Energy is absorbed
• B) Energy is released
• C) Temperature increases
• D) Heat is not involved
• Answer: A

17. The heat of formation of a compound is:

• A) The heat change when one mole of a compound is formed from its elements
• B) The heat change during a phase change
• C) The heat required to break a bond
• D) The heat released during combustion
• Answer: A

18. The standard heat of formation is measured under which conditions?

• A) 1 atmosphere pressure and 25°C
• B) 1 atmosphere pressure and 0°C
• C) 100 kPa pressure and 100°C
• D) None of the above
• Answer: A

19. Which law relates the heat of reaction to the sum of heats of formation of reactants and products?

• A) Hess’s Law
• B) Boyle’s Law
• C) Charles’s Law
• D) Le Chatelier’s Principle
• Answer: A

20. Which of the following reactions releases the most heat?

• A) Combustion of methane
• B) Combustion of glucose
• C) Neutralization of HCl with NaOH
• D) Melting of ice
• Answer: A