Thermodynamics

Question

calculate enthalpy change for reaction 2c+3h2->c2h6.given that sublimation energy of carbon is 716.7 KJ/mol and the bond energy of H-H,C-H,C-C bonds are 433,413,348kJ/mol

Answer 1

2C + 3H2 ==>C2H6

Reactants

716.7 KJ/mole x 2 mole = 1433.4 kJ

433 KJ/mole x 3 moles = 1299 kJ

Products

1C-C = 348 kJ

6 C-H = 6 x 413 kJ = 2478

Total reactants = 1433 + 1299 = 2732 kJ

Total products = 348 + 2478 = 2826 kJ

 2826 - 2732 = 94 kJ = ∆H