Hydrogen peroxide decomposes to form water and oxygen gas

How do the energy differences between the higher energy levels of an atom compare with the energy difference between the lower energy level of the atom

Consider the following reactions. (note: (s) = solid, (l) = liquid, and (g) = gas.) mg(s) + ½o2(g) → mgo(s) + 146 kcal/mole h2(g) + ½o2(g) → h2o(g), δh = -57.82 kcal/mole what type of reaction is represented by the previous two examples?

The excretory system,need answers for all: )