alleryA reaction is found to have $\Delta H = +30\,\text{kJ mol}^{-1}$ and $\Delta S = +100\,\text{J K}^{-1}\,\text{mol}^{-1}$ at $1\,\text{atm}$. The reaction is spontaneous when:
AAt all temperatures
BAt no temperature
C$T > 300\,\text{K}$
D$T < 300\,\text{K}$
Answer & Solution
Correct answer: C. $T > 300\,\text{K}$
$\Delta G = \Delta H - T\Delta S$.
For spontaneity $\Delta G < 0$, so $T > \Delta H/\Delta S = 30{,}000 / 100 = 300\,\text{K}$.
Both $\Delta H$ and $\Delta S$ are positive, so spontaneity is favoured by higher temperature.
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