# The heat of combustion for n-heptane, C_7H_16is 4,817 kJ/mol. How much heat is released if 550 kg of this liquid burns completely?

Jun 16, 2017

Approx. $- 2.7 \times {10}^{8} \cdot k J$

#### Explanation:

We interrogate the combustion reaction of heptane.......

${C}_{7} {H}_{16} \left(l\right) + 11 {O}_{2} \left(g\right) \rightarrow 7 C {O}_{2} \left(g\right) + 8 {H}_{2} O \left(g\right)$

$\Delta {H}^{\circ} = - 4817 \cdot k J \cdot m o {l}^{-} 1$, i.e. $\Delta {H}^{\circ}$ is quoted per MOLE of REACTION as written..........

$\text{Moles of heptane combusted} = \frac{550 \cdot k g \times {10}^{3} \cdot g \cdot k {g}^{-} 1}{100.21 \cdot g \cdot m o {l}^{-} 1}$

$5488.5 \cdot m o l$.

And thus $\Delta {H}_{\text{rxn}}^{\circ} = 5488.5 \cdot \cancel{m o l} \times - 4817 \cdot k J \cdot \cancel{m o {l}^{-} 1}$

$= - 2.64 \times {10}^{8} \cdot k J$