When water enters your stomach, why doesn't your stomach acid react and heat up?

Hey that's not a bad question!

I suppose the answer is volume. the volume of your stomach acid is determined not in a static amount - you don't always have x- ml of stomach acid in your stomach. It is produced when needed.

So, it is only produced when you drink the water. You drink the water, and then the epithelial cells of your stomach produce the acid and it gets diluted. The amounts produced won''t even be CLOSE enough to bring about a significant heat rise - but there probably is a slight one.

Here's a link to gastic acid production if you want to learn more about it:

http://en.wikipedia.org/wiki/Gastric_acid

1

I think the reason that it does not heat up as one would expect is that the acid present in your stomach is already completely dissociated. It is very dilute acid to begin with, and adding additional water does not cause further dissociation of the acid. It is the dissociation of the acid that releases thermal energy since water stabilizes the free ions.

It does!