For the following processes, calculate the change in internal energy of the system and determine whether the process is endothermic or exothermic: (a) A balloon is cooled by removing 0.655 kj of heat. It shrinks on cooling, and the atmosphere does 382 j of work on the balloon. (b) A 100.0-g bar of gold is heated from 25°C to 50°C during which it absorbs 322 j of heat. Assume the volume of the gold bar remains constant. (c) the surroundings do 1.44 kj of work compressing gas in a perfectly insulated cylinder.