Chemical Engineering - Chemical Engineering Thermodynamics - Discussion
Discussion Forum : Chemical Engineering Thermodynamics - Section 1 (Q.No. 23)
23.
No work is done by the system, when a reaction occurs at constant
Discussion:
2 comments Page 1 of 1.
Raj musale said:
1 decade ago
Consider an ideal gas enclosed in a piston cylinder system.
So the energy equation for closed system is Q = delta(E)-W.
Similarly dQ = dU-dW....equation 1.
Now dU = Cp dT and dW = -PdV.
So dQ = Cp dT+RT dV/V.
Now integrating,
Q = integration of Cp dT+RT ln V2/V1.
So Q = integration of Cp dT....equation 2.
Now from equation 1,
dW = dU-dQ.
dW = Cp dT - Cp dT.
= 0.
So answer is A.
So the energy equation for closed system is Q = delta(E)-W.
Similarly dQ = dU-dW....equation 1.
Now dU = Cp dT and dW = -PdV.
So dQ = Cp dT+RT dV/V.
Now integrating,
Q = integration of Cp dT+RT ln V2/V1.
So Q = integration of Cp dT....equation 2.
Now from equation 1,
dW = dU-dQ.
dW = Cp dT - Cp dT.
= 0.
So answer is A.
(2)
Zahraa said:
7 years ago
work =F dL ( force * change in length)
for constant volume ( constant length),
work = 0.
So A is correct.
for constant volume ( constant length),
work = 0.
So A is correct.
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