8.8 The standard enthalpy for selected organic compounds is given in this problem. For each,compute the gross and net heats of combustion. \text { (a) Propane }\left(\mathrm{C}_{3} \mathrm{H}_{4}\right) ;-103.8 \mathrm{k}

\mathrm{j} / \mathrm{mol} \text { (b) } n \text { -Butane }\left(C_{4} H_{10}\right) ;-124.7 k J / m o l