Question

When 0.532g of benzene (C6H6),is burnt with excess of oxygen in a constant volume system, 22.3 KJ of heat is given out . Calculate H for combination reaction ( R=8.314 J \mol)

Answer 1

2 C6H6 + 15 O2 ---------> 12 CO2 + 6 H2O

Molecular mass of C6H6 = 78 g

0.532 g of C6H6 on combustion would give heat = 22.3 KJ

1 g of C6H6 on combustion would give heat = 22.3 / 0.532

78 g of C6H6 on combustion would give = 22.3 / 0.532 x 78

delta H = -3269 KJ