Which of the following statements is true regarding the energy diagram provided?

i. The reaction is endothermic.
ii. The activation energy is +10 kJ.
iii. The reaction releases energy.
iv. The enthalpy of the reaction is –25 kJ.

• A. I only
• B. II and IV
• C. I and III
• D. II, III and IV

Answer: (D)

Verified step by step guidance

1. Examine the energy diagram provided. The y-axis represents Gibbs Free Energy, and the x-axis represents the reaction coordinate.
2. Identify the initial and final energy levels on the diagram. The initial energy level is around 40 kJ, and the final energy level is around 15 kJ.
3. Calculate the change in Gibbs Free Energy (ΔG) by subtracting the final energy from the initial energy: ΔG = Final Energy - Initial Energy. This will help determine if the reaction is endothermic or exothermic.
4. Determine the activation energy by identifying the peak of the energy curve. The activation energy is the difference between the peak energy and the initial energy level.
5. Analyze the statements: i. The reaction is endothermic (ΔG > 0), ii. The activation energy is +10 kJ, iii. The reaction releases energy (ΔG < 0), iv. The enthalpy of the reaction is –25 kJ. Compare these with your findings from the diagram.