One of the ways to destroy chlorinated hydrocarbons in waste streams is to add a fuel $($here toluene waste$)$ and burn the mixture. In a test of the combustion apparatus, $1200lb$ of a liquid mixture composed of $0\mathrm{.}0487\%$ hexachloroethane $(C_{2}C{l}_6),0\mathrm{.}0503\%$ tetrachloroethane $(C_{2}C{l}_4),0\mathrm{.}2952\%$ chlorobenzene $(C_6{H}_{5}Cl),$ and the balance toluene $(C_7{H}_8)$ was burned completely with air. What was the HHV of the mixture calculated using data for the heats of combustion in British thermal units per pound? Compare the resulting value with the one obtained from the Dulong empirical formula?

Heat of combustion $(H_C)$ of $C_2{C}_{16}=828,C_2{C}_{14}=2141Bt\frac{u}{l}b,C_6{H}_{5}Cl=11876Bt\frac{u}{l}b,C_7{H}_8=18246Bt\frac{u}{l}b$

Mol.wt$.$ of $C=12,H=1,Cl=35\mathrm{.}5$