Heat is given off when hydrogen burns in air according to the equation:

2H2 + O2 ---> 2H2)

What is responsible for the heat?

I know the answer is froming hydrogen-oxygen bonds gives off energy, but why?

1 answer

Your answer is close but not quite there I don't think. It takes energy to break the H-H bond and it takes energy to break the O-O bond. Forming the O-H bond produces energy. The sum of forming 4-OH bonds is greater than breaking 2 H-H bonds and 1 O-O bond; therefore, the reaction is exothermic.