Question

For a particular reaction, ΔH∘=67.7 kJ/mol and ΔS∘=126.9 J/(mol⋅K). Assuming these values change very little with temperature, at what temperature does the reaction change from nonspontaneous to spontaneous in the forward direction?T= K Is the reaction in the forward direction spontaneous at temperatures greater than or less than the calculated temperature?greater thanless than

Answer 1

When T > 533.5K, the reaction is spontaneous in the forward reaction.

When T < 533.5K, the reaction is nonspontaneous

Step-by-step explanation:

Using the equation:

ΔG = ΔH - TΔS

Where T is absolute temperature

The ΔG < 0 indicates nonspontaneus reaction, ΔG > 0 indicates spontaneous reaction.

That means:

0J/mol = 67700J/mol - T*126.9J/molK

T*126.9J/molK = 67700J/mol

T = 533.5 K

That means:

When T > 533.5K, the reaction is spontaneous in the forward reaction.

When T < 533.5K, the reaction is nonspontaneous