| \[C\,\text{(graphite)+}\frac{1}{2}{{O}_{2}}\xrightarrow[{}]{{}}CO(g),\] | \[\Delta H_{1}^{o}=-110.5\,\text{kJ}\] |
| \[CO\,\text{(g)}\,\text{+}\frac{1}{2}{{O}_{2}}(g)\xrightarrow[{}]{{}}CO(g),\] | \[\Delta H_{2}^{o}=-282.9\,\text{kJ}\] |
| \[{{H}_{2}}\,\text{(g)}\,\text{+}\frac{1}{2}{{O}_{2}}(g)\xrightarrow[{}]{{}}{{H}_{2}}O(l),\] | \[\Delta H_{3}^{o}=-285.8\,\text{kJ}\] |
| \[C\,\text{(graphite)}\,+2{{H}_{2}}(g)\xrightarrow[{}]{{}}C{{H}_{4}}(g),\] | \[\Delta H_{4}^{o}=-74.8\,\text{kJ}\] |
A) - 750.69 kJ
B) - 820.79 kJ
C) - 720.79 kJ
D) - 1000.79 kJ
Correct Answer: C
Solution :
\[\Delta {{H}^{o}}=-3\Delta H_{1}^{o}+\Delta H_{2}^{o}+2\Delta H_{3}^{o}+3\Delta H_{4}^{o}\] \[=-747.4\,\text{kJ}\] \[\Delta {{H}^{o}}=\Delta U_{{}}^{o}+\Delta ng\,RT\] \[\because \]\[\Delta {{n}_{g}}=-8\] \[-747.4=\Delta {{U}^{o}}-\frac{8\times 8.314\times 400}{1000}\] \[-747.4+26.60=\Delta {{U}^{o}}\] \[\Delta {{U}^{o}}=-720.79\,\text{kJ}\]
You need to login to perform this action.
You will be redirected in
3 sec
