A reaction is non-spontaneous at any temperature whenDelta H is positive and Delta S is positiveDelta H is positive and Delta S is negativeDelta H is negative and Delta S is nega…

Question

asked Aug 20, 2020 231k views

1 Answer

Gcharbon · Answer 1 · 2020-08-24T23:16:21+0000

Answer:

Delta H is positive and Delta S is negative

Step-by-step explanation:

The expression for the standard change in free energy is:

$\Delta G=\Delta H-T* \Delta S$

Where,

$\Delta G$ is the change in the Gibbs free energy.

T is the absolute temperature. (T in kelvins)

$\Delta H$ is the enthalpy change of the reaction.

$\Delta S$ is the change in entropy.

For a reaction to be non spontaneous, it means that:-
$\Delta G>0$

Thus,

$\Delta H-T* \Delta S>0$

For the above conditions to satisfy,
$\Delta H$ must be positive and
$\Delta S$ must be negative.