Question

A system initially has an internal energy E of 501 J. It undergoes a process during which it releases 111 J of heat energy to the surroundings, and does work of 222 J. What is the final energy of the system, in J?

Answer 1

Heat is a way for an object to dump energy into its surroundings (Heat is sort of "garbage" energy. Science has not really figured out any good ways of making it do work. All it does it splatter itself all over other objects), so when your 501 J system releases 111 J of energy, it is just deducting it from 501.

When it "does work" (as opposed to something else doing work on IT), it is also losing energy, but in a more productive way than losing it as heat. It might be pushing another object or something, we dont know. In any case, it loses another 222. So you have you have 501 - 111 - 222 = final energy.

final energy = 168 J