Question

For given reaction at $288K$

$2A_{\left(g\right)}+B_{\left(g\right)}⟶2C_{\left(g\right)}$

If $\Delta U^o=-10kJ/mol$; $\Delta S^o=-45J/mol$
Then what will be value of $\Delta G^o$ for above reaction?

• A. $+560J/mol$
• B. $-25890J/mol$
• C. $2000J/mol$
• D. $8500J/mol$

Answer 1

The correct option is A $+560J/mol$

$2A\left(g\right)+B\left(g\right)\to 2C\left(g\right)$

$T=288K$

$\Delta U^o=-10kJ/mol$

$\Delta H^o=\Delta U^o+\Delta n_{gas}RT$

$=-10kJ+(-1)\times \frac{23}{3}\times \frac{288}{100}$

$=(-10-2.4)kJ$

$=-12.4kJ$

$\Delta G^o=\Delta H^o-T\Delta S^o$

$=(-12.4-\frac{288\times (-45)}{1000})kJ/mol$

$=(-12400+288\times 45)kJ/mol$

$=(12960-12400)J/mol$

$=560J/mol$