When converting from kJ-->mol or mol-->kJ, we use delta H to show us the change in energy.
*Remember sig figs apply to these conversions!
Eg. Calculate the energy absorbed when 50g of BrCl is formed from Br2 and Cl2
Br2 + Cl2 + 100 kJ----> 2BrCl
50g x1 mole of BrCl x 100kJ=
--------------- -------- 21 kJ
When kJ is on the right side, it is an positive, endothermic reaction; when the kJ is on the left, it is an negative, exothermic reaction.