The net enthalpy change of a reaction is the amount of energy required to break all the bonds an reactant molecules amount of energyrequiredto form all the bonds in the product molecules. What will be theenthalpy change for the following reaction : H_(2)(g) + Br_(2) rarr 2HBr(g) Given that bond energy of H_(2), Br_(2) and HBr is435 kJ mol^(-1) , 192 kJ mol^(-1) and 368 kJ mol^(-1) respectively.

The net enthalpy change of a reaction is the amount of energy required

1.	The net enthalpy change of a reaction is the amount of energy required to break all the bonds an reactant molecules amount of energyrequiredto form all the bonds in the product molecules. What will be theenthalpy change for the following reaction : H_(2)(g) + Br_(2) rarr 2HBr(g) Given that bond energy of H_(2), Br_(2) and HBr is435 kJ mol^(-1) , 192 kJ mol^(-1) and 368 kJ mol^(-1) respectively.
Answer» Solution :`H_(2)(G) +Br_(2)(g) rarr 2HBR(g)` `Delta_(r)H^(@) = SigmaBE` ( Reactants)`- Sigma `BE( Products)`= BE ( H_(2)) + BE ( Br_(2)) -2` BE ( HBr) `= 435 +192- ( 2 XX 368 ) KJ mol^(-1)` `=- 109 kJ mol^(-1)`