The following question is a classic "First Law problem", introducing important thermodynamic quantities such as heat and work, and the idea of a state finction. 3. One mole of nitrogen at 273K occupying 10 litres (sate 1) is to be expanded to a volume of 20 litres at 373K (state 2). An infinite number of paths from state 1 to state 2 are possible. Consider the following important paths. a) The gas is expanded isothermally and reversibly at 273K to a volume of 20 litres and then heated to 373K. b) The gas at a volume of 10 litres is heated from 273K to 373K and then expanded isothermally to 20 litres