Notifications
Clear all
0
29/09/2021 12:29 pm
Topic starter
A certain reaction is non-spontaneous at 298K. The entropy change during the reaction is 121 JK–1. Is the reaction is endothermic or exothermic? The minimum value of ΔH for the reaction is
(a) endothermic, ΔH = 36.06 kJ
(b) exothermic, ΔH = -36.06 kJ
(c) endothermic, ΔH = 60.12 kJ
(d) exothermic, ΔH = -60.12 kJ
1 Answer
0
29/09/2021 12:32 pm
Correct answer: (a) endothermic, ΔH = 36.06 kJ
Explanation:
For non spontaneous reaction
ΔG = + ve
ΔG = ΔH – TΔS and
ΔS = 121 JK-1
For ΔG = +ve
ΔH has to be positive. Hence the reaction is endothermic.
The minimum value of ΔH can be obtained by putting ΔG = 0
ΔH = TΔS = 298 × 121 J
= 36.06 kJ