Question

For the reaction $X_2{O}_4\left(l\right)\to 2X{O}_2\left(g\right)$, $\Delta U=2.1Kcal,$ and $\Delta S=20cal{K}^{-1}$ at 300 K. Hence, $\Delta G$ is:

• A. $2.7Kcal$
• B. $-2.7Kcal$
• C. $9.3Kcal$
• D. $-9.3Kcal$

Answer 1

The correct option is B $-2.7Kcal$

As we know,

$\Delta H=\Delta U+\Delta n_{g}RT$

$=2.1\times 2\times 0.002\times 300=3.3Kcal$

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

$=3.3\times -300\times \left(0.02\right)=-2.7Kcal$

Hence, the correct option is $\text{B}$