A freezer sits in a large room. A container of liquid water, with a volume of 4.7 L and at a temperature of 0°C?

A freezer sits in a large room. A container of liquid water, with a volume of 4.7 L and at a temperature of 0°C, is placed in the freezer, where it is completely converted into ice. Throughout the freezing process, the interior of the freezer is maintained at a temperature of 0°C.

(a) Find the change in entropy (in kJ/K) of the water during the freezing process.(b) Find the change in entropy (in kJ/K) of the interior of the freezer (not including the water) during the freezing process.(c) The freezer's coefficient of performance (cooling mode) is 4.00. How much heat (in J) does the freezer expel to the room in which the freezer sits during the freezing process? Give the absolute value.(d) If the room that houses the freezer stays at a constant temperature of 20.0°C, what is the total entropy change (of the water, freezer interior, and the room combined, in kJ/K) during the freezing process?

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  • 2 months ago
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    water 1000kg/m^3

    mass = density of water x V= 1000 x 4.7/1000 =4.7kg

    T= 273k= 0 degree C

    Lf= 334kJ/kg 

    Q= mLf

      = 4.7 x 334 = 1569.8kJ

    a) for water heat is rejected

    ΔS =Q/T=- 1569.8kJ/273 = -5.75kJ/K

    b) for freezer heat is taken= 

    ΔS =Q/T = 5.75kJ/K

    c) COP = 4  = Q/(Qr-Q) =4

    1569.8 / (Qr- 1569.8) = 4

    Qr=1962.25kJ = 1962250J

    d) total ΔS = -5.75 + 5.75 + 1962250/(273 + 20)= 6.70 kJ/k

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