Gibbs-Helmoholtz equation relates the free energy change to the enthalpy and entropy changes of the process as `(DeltaG)_(PT) = DeltaH - T DeltaS` The magnitude of `DeltaH` does not change much with the change in temperature but the enrgy factor `T DeltaS` changes appreciably. Thus, spontaneity of a process depends very much on temperature. For the reaction at `298K, 2A +B rarr C` `Deltah = 100 kcal` and `DeltaS = 0.020 kcla K^(-1)`. If `DeltaH` and `DeltaS` are assumed to be constant over the temperature range, at what temperature will the reaction become spontaneous?A. `1000 K`B. `3500 K`C. `5000 K`D. `1500K`

Gibbs-Helmoholtz equation relates the free energy change to the enthal

1.	Gibbs-Helmoholtz equation relates the free energy change to the enthalpy and entropy changes of the process as `(DeltaG)_(PT) = DeltaH - T DeltaS` The magnitude of `DeltaH` does not change much with the change in temperature but the enrgy factor `T DeltaS` changes appreciably. Thus, spontaneity of a process depends very much on temperature. For the reaction at `298K, 2A +B rarr C` `Deltah = 100 kcal` and `DeltaS = 0.020 kcla K^(-1)`. If `DeltaH` and `DeltaS` are assumed to be constant over the temperature range, at what temperature will the reaction become spontaneous?A. `1000 K`B. `3500 K`C. `5000 K`D. `1500K`
Answer» `DeltaG = DeltaH - T DeltaS` For spontaneous process, `DeltaG =- ve` or `DeltaH lt T DeltaS` `:. T gt (DeltaH)/(DeltaS) = (100K cal)/(0.02 Kcal K^(-1)) = 5000K`

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