yes it won't hurt anything to use it if it is already cooked.
Cooked chili with beef should be good 3 - 5 days stored in the refrigerator.
cooked ground beef
No it should be refrigerated to keep bacteria away.
A lot
i would say so, i wouldn't take the chance
it should wiegh less when cooked
Brown-like cooked ground beef.
how much protein is in cooked ground beef and drained per pound?
100g
If it's covered and refrigerated, probably yes. If it was left out, most likely no. Meat decays relatively quickly and even if it is in a chili it can still spoil.
No, the fat leaves and the beef shrinks.
Fully cooked is the safest, no matter what it has in it raw, if cooked properly and completely it will not survive.