The energy change �H associated with the

Question

reaction NBr3(g) + 3H2O(g) ! 3HOBr(g) + NH3(g)is +81 kJ/mol rxn.
These bond energy values might be useful:O-H 459 kJ/mol; N-H 386 kJ/mol;O-Br 201kJ/mol. The strength of the N Br bond is

Answer 1

△H=bonds broken-bonds formed

Broken Bonds:
O-H=6(459kJ/mol)
N-Br=3(X kJ/mol)
------------
Bonds Broken=2754kJ/mol + 3(X kJ/mol)

Bonds Formed:
O-H=3(459kJ/mol)
O-Br=3(201kJ/mol)
N-H=3(386 kJ/mol)
-------------
Bonds Formed= 3138kJ/mol

+81kJ/mol=[2754kJ/mol + 3(X kJ/mol)]- 3138kJ/mol
* resolve for X

N-Br=155kJ/mol