Question

Standard enthalpy and standard entropy changes for the oxidation of ammonia at 298 K are −382.64 kJ mol⁻¹ and −145.6 JK⁻¹ mol⁻¹, respectively. Standard Gibb's energy change for the same reaction at 298 K is ______.

Options

• −22.1 kJ mol⁻¹

• −339.3 kJ mol⁻¹

• −439.3 kJ mol⁻¹

• −523.2 kJ mol⁻¹

Answer 1

Standard enthalpy and standard entropy changes for the oxidation of ammonia at 298 K are −382.64 kJ mol⁻¹ and −145.6 JK⁻¹ mol⁻¹, respectively. Standard Gibb's energy change for the same reaction at 298 K is −339.3 kJ mol⁻¹.

Explanation:

ΔG = ΔH − TΔS

= −382.64 + (298 × 145.6 × 10⁻³)

= −339.3 kJ mol⁻¹