Thermodynamics And Thermochemistry Result Question 27
27. The standard molar heat of formation of ethane, carbon dioxide and liquid water are $-21.1,-94.1$ and $ -68.3$ kcal respectively. Calculate the standard molar heat of combustion of ethane.
(1986,2 M)
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Answer:
Correct Answer: 27. $(-372$ $ \mathrm{kcal} / \mathrm{mol})$
Solution:
$\Delta H =\Sigma \Delta H_f^{\circ} \text { (products) }-\Sigma \Delta H_f^{\circ} \text { (reactants) } $
$ =-2 \times 94.1-3 \times 68.3-(-21.1) $
$ =-372 $ $\mathrm{kcal} / \mathrm{mol}$
BETA
