Three independent processes are proposed to occur inside an adiabatic

PHYSICS · Subjective · A Level · Physics · Engineering physics · Engineering physics

Problem

Three independent processes are proposed to occur inside an adiabatic, rigid and sealed container that is thermally isolated from the rest of the universe. Process A:

1\,\text{kg}

of water at

-5^{\circ}\text{C}

and

1\,\text{atm}

freezes completely to ice at

-5^{\circ}\text{C}

. Latent heat of fusion of ice

L_f = 3.3\times10^{5}\,\text{J\,kg}^{-1}

. Specific heat of water

c_\text{w}=4200\,\text{J\,kg}^{-1}\text{K}^{-1}

, of ice

c_\text{i}=2100\,\text{J\,kg}^{-1}\text{K}^{-1}

. Melting point of ice

0^{\circ}\text{C}

. (Assume all heat is exchanged with the contents of the container only.) Process B: One mole of an ideal gas at

400\,\text{K}

isothermally compressed reversibly from

10\,\text{L}

1\,\text{L}

. Process C: A heat engine in one cycle absorbs

500\,\text{J}

of heat from a source at

600\,\text{K}

, rejects

300\,\text{J}

to a sink at

300\,\text{K}

and delivers

200\,\text{J}

of work. For each of the above processes, answer the following. (a) Calculate the entropy change of the system involved in the process. (b) Calculate the entropy change of the surroundings inside the container (remember the container is adiabatic to the outside world). (c) Hence compute the total entropy change of the universe for each process and classify each as reversible, spontaneous or impossible. (d) If any two of these processes were to occur simultaneously inside the same isolated container, could the combined set of processes take place without violating the second law? Justify your answer with numerical values.

Related theory

Browse the problem library