Calculate the enthalpy change with the help of Hess’s law for the decomposition of hydrogen peroxide, (2H O (l) 2H O(l) + O (g)), if the enthalpy of formation of water (2H (g) +O (g)) is –512KJ and vaporization of hydrogen peroxide (H O (l) = H (g) + O (g)) is 376 kJ.

a. energy is absorbed in the reaction.

if in a given reaction the energy of products is greater than the energy of reactants it means that reaction is endothermic and during the reaction, the energy is absorbed by reactants. in an endothermic reaction, the products have more stored chemical energy than the reactants. and in this reaction the reactants are more stable than products before the compounds with less energy are always more stable.

they are all solids.