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Grade 12Physical Chemistry

which of rxns are spontaneous at high temp and non spontaneous at low temperature.... wt i hv to do some rxns r given

Profile image of Nishant
11 Years agoGrade 12
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1 Answer

Profile image of Sunil Kumar FP
11 Years ago
we have ΔG=ΔH-TΔS
When ΔS is positive and ΔH is negative, a process is always spontaneous

When ΔS is positive and ΔH is positive, a process is spontaneous at high temperatures, where exothermicity plays a small role in the balance.

When ΔS is negative and ΔH is negative, a process is spontaneous at low temperatures, where exothermicity is important.

When ΔS is negative and ΔH is positive, a process is not spontaneous at any temperature, but the reverse process is spontaneous.