Question

For a particular reaction, ΔH = 134.1 kJ/mol and ΔS = 35.0 J/(mol·K). Calculate ΔG for this reaction at 298 K.

What can be said about the spontaneity of the reaction at 298 K?

() the system is spontaneous as written.

() The system is at equilibrium.

() The system is spontaneous in the reverse direction.

Answer 1

Answer:

The system is spontaneous in the reverse direction

Explanation:

Let's apply the thermodymanic formula for ΔG

ΔG = ΔH - T . ΔS

ΔG = 134100 J/mol - 298K . 35 J/mol.K

(be careful in the units, enthalpy is in kJ and entropy, in J)

ΔG = 123670 J/mol → 123.6 kJ/mol

ΔG = 0 ⇒ System at equilibrium

ΔG  < 0 ⇒ Spontaneous process

ΔG > 0 ⇒ Non spontaneous

In conclussion, the system is spontaneous in the reverse direction.