PP Presentation
Making H2 from liquid H2O involves two steps.
H2O(liq) + 44 kJ ® H2O(g)
H2O(liq) + 286 kJ ® H2(g) + 1/2 O2(g)
This is an example of HESS’S LAW —
If a reaction is the sum of 2 or more others,
the net DH is the sum of the DH’s of the other rxns.