Energy level diagrams show if its exothermic or endothermic
In exothermic reations /\H is -ve
1) This shows an exothermic reaction- the products are at a lower energy than the reactants. The difference in height represents the energy given out in the reaction (per mole). /\H is -ve here.
2) The initial rise in the line represents the energy needed to break the old bonds. This is the activation energy,