| Isothermal change | Adiabatic change |
| 1. Changes in volume and pressure of a gas taking place at constant temperature are called isothermal changes. | 1.Changes in volume and pressure of a gas taking place in a thermally isolated system are called adiabatic changes. |
| 2. Temperature of the gas remains constant. | 2. Temperature of the gas changes. |
| 3. The gas remains in good thermal contact with the surroundings and heat is exchanged. | 3. The gas is isolated from the surroundings and heat is not exchanges ∆Q = O. |
| 4. Internal emergy remains constant. Change in internal energy ∆ U = O. | 4. Internal energy changes. |
| 5. This process takes place slow. | 5. This process takes place quickly |
| 6. Boyle's law PV = Constant holds good | 6. PVr = Constant |
| 7. Workdone W = RT loge(v2/v1) | 7. Work done w = (R/(r - 1))(T1 - T2) |
