First slide

Gibb's Helmholtz equation

Question

A chemical process involves decrease in enthalpy and decrease in entropy. If the magnitude of change in enthalpy is 1000 times the change in entropy, the process is spontaneous at

Difficult

A

1000°c
B

1273°c
C

729°c
D

427°c

Solution

$\begin{matrix} Given ΔH = - Ve and Δs = - Ve; \\ ΔG = ΔH - T ∆ S \end{matrix}$
At equilibrium, $ΔG = 0$
$\begin{array}{l} ∴ T_{eq} = \frac{ΔH}{ΔS} \\ T_{eq} = \frac{1000}{1} \\ T_{eq} = 1000 K \\ T_{eq} = 727^{o} C \\ ΔG = ΔH - TΔS \\ ΔG = - Ve - T (- Ve) \end{array}$
Process becomes spontaneous when $ΔG = - Ve$ which is only possible when temperature is below 1000K (or) 727°c.

Get Instant Solutions

When in doubt download our app. Now available Google Play Store- Doubts App

Recieve an sms with download link

Doubts App

OR

SCAN ME

Doubts App

Doubts App