(a(i))[2]
State the meaning of the internal energy of a system.
(a(ii))[2]
Explain why the internal energy of an ideal gas is directly proportional to the thermodynamic temperature of the gas.
(b)[4]
A sample of an ideal gas has thermodynamic temperature $T$ and internal energy $U$. The gas is compressed so that its temperature rises to $3T$. During this compression, work $W$ is done on the gas. The gas is then cooled at constant volume so that its temperature falls to $2T$. Complete Table 4.1 to show, in terms of some or all of $W$, $T$ and $U$, the work done on the gas, the thermal energy supplied to the gas and the increase in internal energy of the gas for each process.