Final answer:
The work done on an ideal gas when the temperature is raised from T1 to T2 in a thermally isolated system at constant pressure is W = nR(T2 - T1).
Step-by-step explanation:
The expression for the work done (W) on an ideal gas in an enclosed thermally isolated cylinder as the temperature is raised from T1 to T2 is given by the formula W = nR(T2 - T1). This expression holds true when we are considering a process that is carried out at constant pressure, as per the ideal gas law PV = nRT. In this context, as the temperature increases, the volume would expand proportionally to maintain constant pressure since the number of moles (n) and the gas constant (R) are unchanged.
It is important to note that for an adiabatic process, no heat is exchanged with the surroundings and the work done is related to the change in internal energy, which depends on the specific heat capacities of the gas. In contrast, for an isothermal expansion or compression where temperature remains constant, the work done by the gas can be calculated using the formula W = nRTln(V2/V1), which arises from the integration of the pressure volume work done on a gas expanding or compressing quasi-statically.