Analyzing Energy Profiles for Enthalpy and Activation Energy

Steps:

• Locate energy levels of reactants and products on each diagram.
• Compute ΔH for reaction 1: ΔH₁ = E_products₁ - E_reactants.
• Compute ΔH for reaction 2: ΔH₂ = E_products₂ - E_reactants.
• Compare |ΔH₂| and |ΔH₁|; larger difference indicates greater enthalpy change magnitude.

Why D is correct:

• Enthalpy change (ΔH) is the net energy difference between products and reactants; the diagram shows a larger vertical gap for reaction 2.

Why the others are wrong:

• A: Diagrams likely show one exothermic (products lower) and one endothermic (products higher).
• B: Both may be exothermic or one endothermic, but not exclusively reaction 1.
• C: Activation energy is the peak height from reactants; reaction 1's barrier appears equal or larger.

Final answer: D