Question

if the entropy of the universe is ever increasing, what will happen to the energy of the universe?

Answer 1

The first Law of Thermodynamics: the energy of the universe is constant or energy can neither be created or destroyed.

Answer 2

then will all the energy at the end of the universe turn into matter according Einstein's equation E=mc^2? or will all the matter turn into energy?

Answer 3

Same response, here:

>There's an eventual heat-death, where entropy is at a maximum, until a Poincaré point, where the system will come back to some low-entropy state.

Plus, at this point, free-energy is at a minimum, and energy-density is essentially equivalent at all point.

Answer 4

*points.

Answer 5

but that's assuming that the space doesn't expand, but now it is known that space is expanding at an accelerated rate.
so then what happens to all the matter? as space expands, then the entropy of the system constantly increases, and matter wouldn't be stable staying as matter and degenerates into energy. would it not?

Answer 6

Well, yeah, it's been known to expand, and, in reference to the 2012 Nobel Prize in Physics, at an accelerated rate. Matter will not necessarily degenerate into energy, if it is stable, but, it could, spontaneously, although it requires some energy or a probabilistic state to happen.

I'd recommend going through this, first, then asking any questions you may have:
https://en.wikipedia.org/wiki/Heat_death_of_the_universe

Answer 7

what if there's enough metric expansion that the forces keeping matter together aren't strong enough therefore the mass turns into energy?