Calculate the moles of C and moles of H:

$\mathrm{mol}\mathrm{C}\hspace{0.17em}=24.01\overline{)\mathrm{g}{\mathrm{CO}}_{2}}\left(\frac{1\overline{)\mathrm{mol}\hspace{0.17em}{\mathrm{CO}}_{2}}}{44.02\overline{)\mathrm{g}{\mathrm{CO}}_{2}}}\right)\left(\frac{1\mathrm{mol}\hspace{0.17em}\mathrm{C}}{1\overline{)\mathrm{mol}{\mathrm{CO}}_{2}}}\right)\phantom{\rule{0ex}{0ex}}\mathrm{mol}\mathrm{C}\hspace{0.17em}=0.55\mathrm{mol}\mathrm{C}\phantom{\rule{0ex}{0ex}}\phantom{\rule{0ex}{0ex}}\mathrm{mol}\mathrm{H}=4.917\overline{)\mathrm{g}{\mathrm{H}}_{2}\mathrm{O}}\left(\frac{1\overline{)\mathrm{mol}{\mathrm{H}}_{2}\mathrm{O}}}{18\overline{)\mathrm{g}{\mathrm{H}}_{2}\mathrm{O}}}\right)\left(\frac{2\mathrm{mol}\mathrm{H}}{1\overline{)\mathrm{mol}{\mathrm{H}}_{2}\mathrm{O}}}\right)\phantom{\rule{0ex}{0ex}}\mathrm{mol}\mathrm{H}=0.55\mathrm{mol}\mathrm{H}$

A sample of a hydrocarbon is combusted completely in O_{2}(g) to produce 24.01 g CO_{2}(g), 4.917 g H_{2}O(g), and 342 kJ of heat.

Calculate the value of ΔH_{f} per empirical-formula unit of the hydrocarbon.

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