Eli5: How is hydrogen, a potent source of fuel with high energy release, combined with oxygen, a facilitator for combustion and energy release, mix together to make water which we drink like it’s no big deal?

Question

bonus points if you can explain why water has no caloric value, but hydrogen can power huge machinery.

In: 3

Answer 1

Mixing hydrogen and oxygen does not in itself produce water. Reacting hydrogen with oxygen does, that is, hydrogen makes water when burned with oxygen. This reaction naturally also produces a lot of heat and can be violent or even explosive. Water has no caloric value because it does not burn any further. All the energy has already been released by burning hydrogen.