Bond Energies Final 2013 #1

[Aliya Habib 1L]

So even if h202 is being broken down into 02 and h20, are 02 and h20 considered reactants and thus negative in solving for dH?
Basically, how are reactants and products being determined here and how do we determine which set of bonds are positive and negative?

[Chem_Mod]

Delta H of reaction is always relative to the reaction you are working with. So if the reaction specifies breakdown of H₂O₂ into O₂ and H₂O, your products should be O₂ and H₂O, and your reactant should be H₂O₂. I don't have a picture of the problem/solution so I am working with the information listed here.

[Miguel Velasco 2J]

Exactly. Since 02 and H20 were the results of your reaction, they are the products.