Calculate the change in internal energy, ΔU, for a system that does 422 J of work and loses 227 J of energy as heat

Question

Calculate the change in internal energy, ΔU, for a system that does 422 J of work and loses 227 J of energy as heat.

Answer 1

∆U = q + w

q = heat = -227 J (negative because the system is losing heat, i.e. exothermic)

w = -422 J (negative because the system is doing work on the surroundings)

∆U = -227 J + -422 J = -649 J