# What is the standard enthalpy change of combustion of ethane?

Dec 31, 2016

Got me..........

#### Explanation:

The standard enthalpy of combustion is the enthalpy associated with the combustion of one mole of substance under standard conditions. And thus for ethane it is the enthalpy associated with the following reaction:

${C}_{2} {H}_{6} \left(g\right) + \frac{7}{2} {O}_{2} \left(g\right) \rightarrow 2 C {O}_{2} \left(g\right) + 3 {H}_{2} O \left(l\right) + \Delta$

My old notes say $\Delta {H}_{\text{combustion}}^{\circ} = - 1560 \cdot k J \cdot m o {l}^{-} 1$

But how can I have a negative energy?