Check this question. I found it in Jan 2012 Chem Unit 1.(Original post by FemaleBo55)
These are the two main enthalpy level diagram; a reaction iseither exothermic or endothermic.
Always for an exothermic reaction the products would havelower energy than its reactants, this is because when they form a bond energyis released rather than absorbed. Whereas for the endothermic enthalpy diagramyou can tell that you would need to put high amounts of energy to form thebonds of the products hence the positive enthalpy change value.
What do you think?