A gas is compressed when the surroundings perform 125 J of work on it, and during the compression the gas releases 250 J of heat to the surroundings. What is the change in internal energy, ΔU, of the gas, and is the overall process endothermic or exothermic?
a) ΔU=−375J; process is exothermic
b) ΔU=+250J; process is endothermic
c) ΔU=−125J; process is exothermic
d) ΔU=−125J; process is endothermic