The temperature inside the refrigerator is 2.0 C. It stands in a kitchen whose t

Question

The temperature inside                 the refrigerator is 2.0 C. It stands in a kitchen whose temperature is 22 C. After a period of an hour, 95 kJ of heat are transferred from the interior of the                 refrigerator to the kitchen.

As a result of this heat transfer, what is the entropy change of (i) the contents of the refrigerator, and (ii) the kitchen? (Assume                 that the heat transfer is reversible.)

State the principle of entropy increase. Are your answers to the above compatible with this principle? If not,                 suggest an explanation (one or two sentences).             

Explanation / Answer

COP(coefficient of performance)= k = Qc / W = Tc / Th-Tc=275/(295-275)=13.75

Qc= - 95Kj

W = Qc / COP= 95kj / 13.75
W = 6.909Kj
Qh = Qc+W = 95Kj + 6.909 =101.909Kj

DeltaSc = Qc/T = -95Kj/275= -.345 KJ/K
DeltaSh = Qh/T = 101.909/295 = 0.345 KJ/K

So overall Change in Entropy DeltaS = 0

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