Consider the thermodynamic processes below where 3.0 moles of an ideal gas is ta
ID: 1429249 • Letter: C
Question
Consider the thermodynamic processes below where 3.0 moles of an ideal gas is taken through a cyclic process from stale 1 to state 2 to state 3, and back to state 1. Complete the corresponding state and process tables. If this is a heal engine, determine its efficiency. Also determine the maximum efficiency possible within these temperatures. If this a thermal pump, determine its coefficient of performance once as if it was operating as a refrigerator, and a second time as a heat pump. Clearly indicate which is which. Now consider the reverse cycle and redo part (b). An inventor claims to have designed a heat engine with an efficiency of 20% that operates between the boiling point and freezing point of water. Is this possible? Justify your answer. The coefficient of performance of a particular refrigerator is 4.2 when 8.2 x 10^3J of heat is removed from the inside in each cycle. Find the work done by the compressor per cycle. Find the heat dumped into the kitchen in one cycle.Explanation / Answer
n = 3 mol
for state 1: Using Gas equation PV = nRT
1.5 x 10^5 x V = 3 x 8.314 x 290
V = 0.048 m^3
for state 2:
Volume is constant for transition from 1 to 2.
V = 0.048 m^2
PV = nRT
(3 x 10^5)(0.048) = 3 x 8.314 x T
T = 580 K
for state 3:
state 2 to 3 -> Pressure is constant
P = 3 x 10^5 Pa
PV = n RT
3 x 10^5 x 0.020 = 3 x 8.314 x T
T =240.56 K
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for 1-2 :
volume of constant. In this process work done = 0
W = 0
deltaU + W = Q + = 1.79 x 10^4 (first law of thermodynamics)
for 2 -> 3
Pressure is constant so work done = p deltaV
W = 3 x 10^5 ( 0.020 - 0.048) = - 8.4 x 10^3 J
- 2.1 x 10^4 - - 8.4 x 10^3 J= Q
Q = - 2.94 x 10^4 J
for 3 to 1:
for this cyclic process,
deltaU = 0
so 1.79x 10^4 + (-2.1 x 10^4) + dletaU = 0
deltaU = 0.31 x 10^4 J = 3.1 x 10^3 J
W = area ander tha curve
W = area of traingle + area of rectangle = 1.5 x (area of triangle)
W = 1.5 x (3-1.5) x 10^3 x (0.048 - 0.02) = 6300 J
Q = deltaU + W = 6300 + 3100 = 9400 J
Please don't post so many parts in a single question.