Thermodynamics

The enthalpy of formation of ethane \((\mathrm{C}_2 \mathrm{H}_6)\) from ethylene by addition of hydrogen where the bond-energies of \(\mathrm{C}-\mathrm{H}, \mathrm{C}-\mathrm{C}, \mathrm{C}=\mathrm{C}, \mathrm{H}-\mathrm{H}\) are \(414 \mathrm{~kJ}, 347 \mathrm{~kJ}, 615 \mathrm{~kJ}\) and \(435 \mathrm{~kJ}\) respectively is \(-\) __________ \(\mathrm{kJ}\)