| Isothermal changes | Adiabatic changes |
| 1. Temperature (T) remains constant, i.e., ΔT = 0. | Heat constant (Q) remains constant, i.e., ΔQ = 0. |
| 2. System is thermally conducting to the surroundings. | System is thermally insulate from the surroundings. |
| 3. The changes occur slowly. | The changes occur suddenly. |
| 4. Internal energy (U) remains constant i.e.,ΔU = 0. | Internal energy changes, U ≠ constant.ΔU≠ 0. |
| 5. Specific heat becomes infinite. | Specific heat becomes zero. |
| 6. Equation of isothermal changes is pV = constant. | Equation of adiabatic changes is pVt =constant. |
| 7. Slope of isothermal curve, dp/dV = -(P/V) | Slope of adiabatic curve, dp/dV = -Y(P/V) |
| 8. Coefficient of isothermal elasticity, Ei = p | Coefficient of adiabatic elasticity Ea = γp. |
