Trichloroethylene, a widely used degreasing solvent for machineparts is produced in a two-step reaction sequence. Ethylene isfirst chlorinated to yield tetrachloroethane, which isdehydrochlorinated to form trichloroethylene.
C2H4 (g) + Cl2 (g) ? C2H2C14 (1) + H2 (g): ?H?? = �385.76kJ/mol
C2H2C14 (l) ? C2HCl3 (l) + HC1 (g)
The standard heat of formation of liquid trichloroethylene is�276.2 kJ/mol
(a) Use the given data and tabulated standard heats of formation ofethylene and hydrogen chloride to calculate the standard heat offormation of tetrachloroethane and the standard heat of the secondreaction.
(b) Use Hess�s law to calculate the standard heat of the reactionC2H4 (g) + 2 C12 (g) � C2HCI3 (l) + H2 (g) + HCI (g)
(c) If 300 mol/h of C2HCl3 (l) is produced in the reaction of part(b) and the reactants and products are all at 25�C and I atm, howmuch heat is evolved or absorbed in the process? (Assume Q =?H)
