let's take the combustion of an hydrocarbon CH4 + O2 = CO2 + H20 the products of this reaction is: 1) large heat 2) large amount of gases 3) high kinetic velocity of gases 4) heat of gases what is the exact thing we take advantage in internal combustion engines? the large amount of gases produced? (given the equation, it doesn't seem there are much more gases produced) the heat? (I think it is a by product that is waste) the high kinetic energy of the gases? (so it's the kinetic energy of the gases and not their amount?) the high heat of the gases (so basically the high heat produced makes the gases have high kinetic energy?) also, where exactly the energy comes from in atomic level? thanks!