Calculate the bond dissociation energy (in kJ/mol) of the C-H bond in methane (CH4) using the following data: - The enthalpy change for the combustion of one mole of methane gas is -890.3 kJ/mol.- The energy required to break one mole of H-H bonds is 433.4 kJ/mol.- The energy required to break one mole of C=O bonds is 799.5 kJ/mol.- The energy required to break one mole of O-H bonds is 463.0 kJ/mol.

Question

Calculate the bond dissociation energy (in kJ/mol) of the C-H bond in methane (CH4) using the following data: - The enthalpy change for the combustion of one mole of methane gas is -890.3 kJ/mol.- The energy required to break one mole of H-H bonds is 433.4 kJ/mol.

Answer 1

To calculate the bond dissociation energy of the C-H bond in methane, we need to consider the balanced chemical equation for the combustion of methane:CH g  + 2O g   CO g  + 2HO g Now, let's analyze the bonds broken and formed during this reaction:Bonds broken:1 C-H bond in CH  which we want to find 2 O=O bonds in OBonds formed:2 C=O bonds in CO4 O-H bonds in 2HOUsing Hess's Law, we can write the enthalpy change for the combustion of methane as:H_combustion =  E_bonds_broken -  E_bonds_formedGiven:H_combustion = -890.3 kJ/molE H-H  = 433.4 kJ/molE C=O  = 799.5 kJ/molE O-H  = 463.0 kJ/molLet E C-H  be the bond dissociation energy of the C-H bond in methane. Then:-890.3 kJ/mol = [E C-H  + 2 * 433.4 kJ/mol] - [2 * 799.5 kJ/mol + 4 * 463.0 kJ/mol]Now, we can solve for E C-H :E C-H  = -890.3 kJ/mol + 2 * 799.5 kJ/mol + 4 * 463.0 kJ/mol - 2 * 433.4 kJ/molE C-H  = -890.3 + 1599 + 1852 - 866.8E C-H  = 1694.7 kJ/molTherefore, the bond dissociation energy of the C-H bond in methane is approximately 1694.7 kJ/mol.