- #1
jasc15
- 162
- 5
Im studying for the Fundamentals of Engineering exam (coming up April 12!) and came across this Thermodynamics problem in my review book.
So the work for an isothermal process is RTA*ln(VB/VA), where VA was previously determined to be 0.103m3.
In the solution to the problem, the RTA term is replaced with PA*VA, where it should be (PA*VA)/n from the ideal gas law.
Is this solution wrong? As I see it, this can't be solved without knowing the number of moles of gas (or mass of the gas depending on which R is used). I was unable to get the correct answer, and the solution seems wrong to me.
A gas goes through the following processes:
A to B: isothermal compression
B to C: isochoric compression
C to A: isobaric expansion
PC = PA = 1.4bar
VC = VB = 0.028m3
The net work during the C-to-A process is WCA = 10.5kJ
What work is performed in the A-to-B process?
So the work for an isothermal process is RTA*ln(VB/VA), where VA was previously determined to be 0.103m3.
In the solution to the problem, the RTA term is replaced with PA*VA, where it should be (PA*VA)/n from the ideal gas law.
Is this solution wrong? As I see it, this can't be solved without knowing the number of moles of gas (or mass of the gas depending on which R is used). I was unable to get the correct answer, and the solution seems wrong to me.