Bond energies question!?

Question

NBr3 + 3H2O --> 3HOBr + NH3
The energy exchange associated with this reaction in -81 kJ.
Use this information to calculate the energy of the N-to-Br bond. Assume all atoms other than hydrogen obey the octet rule.

Thanks!!! Any help is welcome!!

Answer 1

Bonds broken = 3 x N-Br and 6 x O-H

Bonds formed = 3 x O-H, 3 x O-Br and 3 x N-H

You are told that bonds broken - bonds formed = -81kJ/mol.

Three of the O-H bonds cancel out, but now all you have to do is look up the relevant bond energies, and work out N-Br.