Question

For a particular reaction, Δ H = 120.5 kJ / mol and Δ S = 758.2 J / ( mol⋅K). Calculate Δ G for this reaction at 298 K. Δ G = kJ / mol What can be said about the spontaneity of the reaction at 298 K? The system is at equilibrium. The system is spontaneous in the reverse direction. The system is spontaneous as written.

Answer 1

ΔG = -105.4 kJ/mol

The system is spontaneous as written.

Step-by-step explanation:

Step 1: Determine Gibbs free energy of reaction (ΔG)

We use the following expression.

ΔG = ΔH - T × ΔS

where,

• ΔH: enthalpy of reaction

• T: absolute temperature

• ΔS: entropy of reaction

ΔG = ΔH - T × ΔS

ΔG = 120.5 kJ/mol - 298 K × 0.7582 kJ/mol.K

ΔG = -105.4 kJ/mol

Step 2: Determine the spontaneity of the system.

Since ΔG < 0, the system is spontaneous as written.