To avoid needlessly long descriptions, we can use diagrams to show the processes that take place in a container of gas.A graph of pressure vs volume (\(pV\) diagram) enables us to show all possible types of process because of the interrelationship between pressure, volume and temperature in the ideal gas law: \(pV\propto T\)We can use the first law to consider the changing heat, internal energy and work done: \(Q=\Delta U+p\Delta V\)