Question

For a particular reaction, $ΔH=-38.3kJ$ and $ΔS=-113JK^{- 1}mol^{- 1}$ . This reaction is:

• A. spontaneous at all temperatures
• B. non-spontaneous at all temperatures
• C. spontaneous at temperatures below $66^\circ C$
• D. spontaneous at temperatures above $66^\circ C$

Answer 1

Answer: (D)

$ΔG=ΔH-TΔS$
For $ΔG=0$
$T=\frac{ΔH}{ΔS}$
$=\frac{- 38 . 3 \times 10^{3}}{113}$
$=338.9K$
$\left(65 . 78 ^\circ C\right)$