Question

The factor of $\Delta G$ value is important in metallurgy. The $\Delta G$ value for the following reactions at ${800}^{o}C$ are given as:
$S_2\left(g\right)+2O_2\left(g\right)\to 2S{O}_2\left(g\right);△G=-544kJ$
$2Zn\left(s\right)+S_2\left(g\right)\to 2ZnS\left(s\right);△G=-293kJ$
$2Zn\left(s\right)+O_2\left(g\right)\to 2ZnO\left(s\right);△G=-480kJ$
The $\Delta G$ for the reaction,
$2ZnS\left(g\right)+3O_2\left(g\right)\to 2ZnO\left(g\right)+2S{O}_2\left(g\right)$ will be :

• A. $-357$ kJ
• B. $-731$ kJ
• C. $-773$ kJ
• D. $-229$ kJ

Answer 1

Answer: (B)

$-731$ kJ

$\Delta G$ of the reaction is given by:

$\Delta G_{reaction}=\Delta G_1-\Delta G_2+\Delta G_3$

$\Delta G_{reaction}=-544+293-480=-731KJ$