In: Physics
A system expands by 0.73 m3 at a constant pressure of 124 kPa . Part A Find the heat that flows into or out of the system if its thermal energy increases by 65 J. Express your answer to two significant figures and include the appropriate units. Q =
Part B
Give the direction of heat flow.
Give the direction of heat flow.
into the system | ||||||
out of the system Part C Find the heat that flows into or out of the system if its thermal energy decreases by 1850 JJ. Express your answer to two significant figures and include the appropriate units.
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A)
U = internal energy change = 65 J
W = work done
V = Change in volume = 0.73 m3
P = Pressure = 124 kPa = 124000 Pa
Work done is given as
W = P V
W = (124000) (0.73)
W = 90520 J
Q = Heat energy
According to first law of thermodynamics
Q = W + U
Q = 90520 + 65
Q = 90585 J
In two significant figure
Q = 9.1 x 104 J
B)
So Heat flows into the system
C)
U = internal energy change = - 1850 J
W = work done
V = Change in volume = 0.73 m3
P = Pressure = 124 kPa = 124000 Pa
Work done is given as
W = P V
W = (124000) (0.73)
W = 90520 J
Q = Heat energy
According to first law of thermodynamics
Q = W + U
Q = 90520 - 1850
Q = 88670 J
In two significant figure
Q = 8.9 x 104 J
In two significant figure.
heat flows into the system