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(i) State hess's law. (ii) For the fol...

(i) State hess's law.
(ii) For the following reaction at 298K
`2X+Y to Z`
`DeltaH=300kJ*mol^(-1) and DeltaS=0.2kJ*K^(-1)*mol^(-1)`
At what temperature will the reaction become spontaneous considering `DeltaH and DeltaS` to be constant over the temperature range?

Text Solution

Verified by Experts

(i)
(ii) For spontaneous process, `Delta G lt0`
`therefore DeltaH-TDeltaS lt0 or, DeltaH lt T DeltaS or, (DeltaH)/(DeltaS)ltT`
or, `(300)/(0.2) lt T or, 1500 lt T`
Therefore, the given reaction becomes spontaneous above 1500 K temperature.
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