Question

$S{O}_2\left(g\right)+1/2O_2\left(g\right)\rightleftharpoons S{O}_3\left(g\right)\Delta H_{298}^o=98.32kJ/mole,\Delta S_{298}^o=95.0J/K/mole$.

Find the $K_p$ for this above reaction at 298K:

• A. $K_P=9.31\times {10}^{-12}at{m}^{1/2}$
• B. $K_P=5.34\times {10}^{-13}at{m}^{1/2}$
• C. $K_P=3.7\times {10}^{-13}at{m}^{1/2}$
• D. $K_P=3.7\times {10}^{-14}at{m}^{1/2}$

Answer 1

The correct option is B $K_P=5.34\times {10}^{-13}at{m}^{1/2}$

$\Delta G^0=\Delta H^0-T\Delta S^0$

$\Delta G^0=98.32\times 1000-298\times 95.0=70010J/mol$

$\Delta G^0=-RTln{K}_P$

$70010=-8.314\times 298\times lnK$

$lnK=-28.26$

$K=5.34\times {10}^{-13}$