Question

ΔH for the reaction is − 110 kJ, and ΔS is + 40 JK⁻¹ at 400 K. The free energy change for the reaction is ______.

Options

• − 110 kJ

• − 8 kJ

• − 126 kJ

• + 8 kJ

Answer 1

ΔH for the reaction is − 110 kJ, and ΔS is + 40 JK⁻¹ at 400 K. The free energy change for the reaction is 126 kJ.

Explanation:

ΔH = − 110 kJ, T = 400 K

ΔS = + 40 JK⁻¹ = 0.04 kJK⁻¹

ΔG = ΔH − TΔS

= − 110 − 400 × 0.04

= − 110 − 16

∴ ΔG = − 126 kJ