Question

The value of $△$H and $△$S for the reaction, $C_{\left(graphite\right)}+{CO}_{2\left(g\right)}\to 2{CO}_{\left(g\right)}$ are 170kJ and ${170JK}^{-1}$, respectively. This reaction will be spontaneous at:

• A. 510K
• B. 710K
• C. 910K
• D. 1119K

Answer 1

Answer: (D)

1119K

$C_{\left(graphite\right)}+C{O}_2\left(g\right)\to 2CO\left(g\right)$

The $Rn$ is spontaneous when $\Delta G⩽O$

$\Rightarrow \Delta H-T\Delta S\le O$

$\Rightarrow T\Delta S⩾\Delta H$

$\Rightarrow T⩾\frac{\Delta H}{\Delta S}$

$T⩾\frac{170\times {10}^3}{1170}$

$T⩾1000K$