Answer to Question #334017 in Physical Chemistry for tma

Question

Express the standard reaction enthalpy of the reaction, C₂H₆ (g) + 7/2 0₂ (g) --> 2C0₂ (g) + 3 H₂ 0(1). Given the standard enthalpy for formation of C₂H₆, CO₂and H₂O are -84.6, -393.5 and -285.8 kJ mol^-1 respectively.

Answer 1

C₂H_6(g) + 7/2O_2(g) --> 2CO_2(g) + 3H₂O_(l)

∆_rH = 2∆_fH(CO₂) + 3∆_fH(2H₂O) - ∆_fH(C₂H₆) = 2*-393,5 + 3*-285,8-1*-84,6 = -1559.8  kJ mol^-1