What is theheat of formation of C_(6)H_(6), given that the heats of combustion of benzene, carbon and hydrogen are 782, 94 and 68K. Cal respectively

What is theheat of formation of C_(6)H_(6), given that the heats of co

1.	What is theheat of formation of C_(6)H_(6), given that the heats of combustion of benzene, carbon and hydrogen are 782, 94 and 68K. Cal respectively
Answer» `+14` KCAL `-14` kCal `+28` kCal `-28` kCal Solution :`C_(6)H_(6) + (15)/(2)O_(2) rarr 6CO_(2) + 3H_(2)O` `DELTA H_("comb") = 6 Delta H_(f_(CO_(2))) + 3 Delta H_(f_(H_(2)O)) - Delta H_(f_(C_(6)H_(6)))` `-782 = 6 XX (-94) + 3 xx (-68) - Delta H_(f_(C_(6)H_(6)))` `rArr Delta H_(f_(C_(6)H_(6))) = + 14` Kcal