Question

At $25^{\circ }C$, the enthalpy of the following processes are given:
$H_2(g)+O_2(g)\to 2OH(g)\Delta H^{\circ }=78kJmo{l}^{-1}$
$H_2(g)+1/2O_2(g)\to H_{2}O(g)\Delta H^{\circ }=-242kJmo{l}^{-1}$
$H_2(g)\to 2H(g)\Delta H^{\circ }=436kJmo{l}^{-1}$
$1/2O_2(g)\to O(g)\Delta H^{\circ }=249kJmo{l}^{-1}$
What would be the value of $X$ for the following reaction?______ (Nearest integer)
$H_{2}O(g)\to H(g)+OH(g)\Delta H^{\circ }=XkJmol-1$

Answer 1

Answer: 499