Exercise 12 | Lewis Formulas

Balance the following reaction and calculate its change in enthalpy ΔH0.

C6H5COOH + O2 → CO2 + H2O


Data:

Bond energy (BE):

H-H = 436 kJ.mol-1

C-H = 413 kJ.mol-1

C-C = 347 kJ.mol-1

C=C = 607 kJ.mol-1

C-0 = 358 kJ.mol-1

C=0 = 805 kJ.mol-1

O-O = 204 kJ.mol-1

O=O = 498 kJ.mol-1

O-H = 464 kJ.mol-1

 

2 C6H5COOH + 15 O2 → 14 CO2 + 6 H2O

ΔH0 = 6 BE (C=C) + 8 BE (C-C) + 2 BE (C=O) + 2 BE (C-O) + 2 BE (O-H) + 10 BE (C-H) + 15 BE (O=O)
             - 28 BE (C=O) – 12 BE (O-H)

         = -6836 kJ.mol-1