The standard heats of combustion \(\left(\Delta H^{\circ}\right)\) per mole of
1,3-butadiene, \(\mathrm{C}_{4} \mathrm{H}_{6}(\mathrm{g}) ;\) butane,
\(\mathrm{C}_{4} \mathrm{H}_{10}(\mathrm{g}) ;\) and
\(\mathrm{H}_{2}(\mathrm{g})\)
are \(-2540.2,-2877.6,\) and \(-285.8 \mathrm{kJ},\) respectively. Use
these data to calculate the heat of hydrogenation of 1,3-butadiene to butane.
$$\mathrm{C}_{4} \mathrm{H}_{6}(\mathrm{g})+2 \mathrm{H}_{2}(\mathrm{g})
\longrightarrow \mathrm{C}_{4} \mathrm{H}_{10}(\mathrm{g}) \quad \Delta
H^{\circ}=?$$
[Hint: Write equations for the combustion reactions. In each combustion, the
products are \(\mathrm{CO}_{2}(\mathrm{g})\) and \(\left.\mathrm{H}_{2}
\mathrm{O}(1) .\right]\)