Question

H-E-L-P!!!!

Answer 1

The enthalpy change of the reaction is positive since it is the difference between the final P.E and initial P.E.
So the reaction tends to increase the P.E,Therefore energy is absorbed in the reaction making it endothermic.

Answer 2

In other words A is the P.E of reactants and C is the P.E of products.C is higher than A so there is a net gain in P.E. Also B is the activation energy and is always higher than A and C.

Answer 3

kartiksriramk short and sweet ;) if you need more extensive answer please visit closed questions cause there are at least 10 same questions answered of which i have extensively answered one, i know my answer is not helping directly but if you look in to it you will find your answer ;)