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

You can think of water as the “ash” left over from burning hydrogen. It’s gotten all the energy out of its system and it’s incredibly stable; it takes that much energy and more to rip it back apart.

Similarly, sodium is a fairly reactive alkali metal, and chlorine gas will tear your lungs up good. But you put salt (sodium chloride) on your food like it’s no big deal.