Question
What will be the standard internal energy change for the reaction at $$298\,K?$$
$$O{F_{2\left( g \right)}} + {H_2}{O_{\left( g \right)}} \to {O_{2\left( g \right)}} + 2H{F_{\left( g \right)}};$$ $$\Delta {H^ \circ } = - 310\,kJ$$
A.
- 312.47$$\,kJ$$
B.
- 125.03$$\,kJ$$
C.
- 310$$\,kJ$$
D.
- 156$$\,kJ$$
Answer :
- 312.47$$\,kJ$$
Solution :
$$\Delta {H^ \circ } = \Delta {U^ \circ } + \Delta {n_g}RT$$
$$\Delta {H^ \circ } = - 310\,kJ,\Delta {n_g} = 3 - 2 = 1,$$ $$R = 8.314 \times {10^{ - 3}}\,kJ\,{k^{ - 1}}\,mo{l^{ - 1}},$$ $$T = 298\,K$$
$$\eqalign{
& \Delta {U^ \circ } = - 310 - \left( {1 \times 8.314 \times {{10}^{ - 3}} \times 298} \right) \cr
& \,\,\,\,\,\,\,\,\,\,\,\,\, = - 312.47\,kJ \cr} $$