Question

Given standard enthalpy of formation of $CO$ and $CO _{2}$ are $\left(-110 \,kJ\, mol ^{-1}\right)$ and $\left(-394 \,kJ\, mol ^{-1}\right)$ respectively. The heat of combustion when one mole of graphite burns is

• A. $-110 \,kJ$
• B. $-284\,kJ$
• C. $-394\,kJ$
• D. $-504\,kJ$

Answer 1

Answer: (C)

Combustion of graphite, $C + O _{2} \rightarrow CO _{2}$

$\Delta H=-394\, kJ\, mol ^{-1}=$ heat of formation of $CO _{2}$