1. Calculate the change in internal energy of the following system: a balloon is cooled by removing 0.657 kJ of heat. It shrinks on cooling, and the atmosphere does 384J work on the balloon.
2. Calculate the change in internal energy in the following system: a 100.0 g 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.