Question

The combustion of hexane is given by the following reaction. 2 C 6 H 14 + 19 O 2 → 12 CO 2 + 14 H 2 O The enthalpy of reaction is −4163.0 kJ/mol. How much energy (in joules) will be released if 72.78 grams of hexane is burned. (Molar mass of hexane = 86.20 g/mol).

Answer 1

Answer:

$E=3.5149kJ$

Explanation:

Hello.

In this case, for such combustion of hexane which release heat, we can compute that amount by taking into account that the reaction releases 4163.0 kJ of energy every 1 mole of hexane, it means that for 72.78 g, which in moles is:

$n_{hexane}=72.78g*\frac{1mol}{86.20g}=0.8443mol$

Thus the energy released when 0.8443 moles of hexane are released turn out:

$E=n_{hexane}\Delta _cH=0.8443mol*-4163.0\frac{kJ}{mol}*\frac{1000J}{1kJ} \\\\E=3.5149kJ$

Best regards!