When bonds are formed, energy is released. in a water molecule, the two hydrogens are both bonded by single bonds to the central oxygen atom. the bond energy associated with an o–h bond is 463 kj/mol. again, using the balanced chemical equation shown above, how much energy is released in forming the o–h bonds?

The balanced chemical equation is:

2H2 + O2 → 2H2O

Based on the reaction stoichiometry:

2 moles of water are formed.

Each water molecule has 2 O-H. Thus, a total of 4 O-H bonds are formed.

Energy released/O-H bond = 463 kJ/mol

For 4 O-H bonds this would be= 4 * 463 = 1852 kJ

Ans: Thus, -1852 kJ (negative sign indicates that energy is released) in the forming of O-H bonds.