Question

Distinguish between isothermal process and adiabatic process.

Answer 1

No	Isothermal process	Adiabatic process
1	The temperature of system remains constant (ΔT = 0).	The temperature of system changes i.e. increases or decreases (ΔT ≠0).
2	System can exchange heat with the surroundings (q ≠ 0).	System cannot exchange heat with the surroundings (q = 0).
3	The internal energy of the system remains constant (ΔU = 0).	The internal energy of the system changes (ΔU ≠ 0).
4	System is not thermally isolated from its  surroundings.  Hence, open or closed system is required.	System is thermally isolated from its surroundings.  Hence, isolated  system is required.
5	In this ΔU = 0, hence q = -W.	In this q = 0, hence ΔU = W.
6	Enthalpy remains constant (ΔH = 0).	Enthalpy changes in this process (ΔH ≠ 0).
7	Expansion takes place by absorbing heat from  surroundings	Expansion takes place by utilizing internal energy of the system
8	Heat supplied is used only for doing work.	Work done is only at the cost of internal energy.
9	Compression takes place by  losing heat to the surroundings.	Compression takes place by adding heat into internal energy of the system.
10	Fusion of ice.	Expansion of gas in vacuum.