[computerphage]

In what way is it not true? When a reaction does convert mass to energy we call it a nuclear reaction

[philwelch]

This is kind of pedantic, but to my understanding, even normal exothermic chemical reactions do convert mass to energy. It’s just that the amount of mass lost is extremely negligible. Conservation of mass is an oversimplification that is close enough to match any real world measurement you’d care about.

Nuclear reactions are when you start getting into doing mass-energy conversion at scale.

[jhrmnn]

Yes, conservation of mass is to conservation of energy what Newtonian mechanics is to general relativity. The former work pretty well in everyday life

[computerphage]

Thank you. I didn't know that.

[ThePadawan]

In much the same way that no electrical device actually "consumes energy" (conservation of energy).

Your power company still won't accept that perfectly correct explanation in lieu of payment.

[p1mrx]

Chemical reactions also lose mass according to E=mc^2, but m is so small that it's hard to notice.

[delecti]

Yup. For example (which I calculated because I was curious), the direct mass conversion equivalent for 2000 food calories of energy is about 93 nanograms. Compare that to the typical value that 1lb of fat is about 3500 calories of usable energy.