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and is brought to a temperature of 400 K over 2 steps where temperature is
first brought to T = 350 K and then to 400K by contact with appropriate
thermal reservoirs. Treat the combination of the Cu block and the thermal
reservoir at every step to be an isolated system. Compute ∆S for the
process and compare your results with that of the previous problem. Can
you comment on the results.
when one mole of copper (initially at 500 K) is brought into thermal equi-
librium with a thermal reservoir at 400 K. Consider one mole of copper
and the thermal reservoir to form an isolated system. [Hints: 1. Thermal
reservoirs are chambers which are always maintained at the same temper-
ature irrespective of the temperatures of the objects in contact with it, 2.
S is an extensive state function.]
(b) Comment whether the process is reversible or irreversible.
rated by an (internal) insulating wall. Initially, the first piece is at 500K
and the second is at 300K. Calculate the entropy change in the sys-
tem when the insulating wall is removed; assume that each piece has
half a mole of copper in it. Given: Specific heat capacity of Cu is
CP = 22.6JK−1mol−1
.
A mass of gas at an initial internal energy of 300 kJ is allowed to expand behind a piston untill it's internal energy is 200 kJ, the value of final pressure and volume are 4.59 bar and 0.148 m^3 respectively, the law of expansion is PV^2 =C calculate
1) work done
2) initial volume.
Air flows steadily at a rate of 0.85 kg/s through an air compressor, entering at 10 m/s speed, 150 KPa pressure and 1.35 m3/kg specific volume and leaving at 8 m/s and 0.53 m3/kg.
Determine the value of leaving pressure and the change in specific enthalpy if the internal energy of the air entering is 105 KJ/kg greater than that of the air leaving. Cooling water in the compressor jackets add heat to the air at the rate of 60KW and the work done on the system is 106.58 kW
