Calculating Internal Energy Change: Path 2 of Carnot Cycle Question

Click For Summary
SUMMARY

The discussion focuses on calculating the internal energy change of a gas during path 2 of the Carnot cycle, which involves a pressure reduction at constant volume followed by an expansion at constant pressure. The key equations referenced include ΔE=Q-W, where W is calculated using W=nRTln(Vf/Vi) and W=∫PdV. The user attempts to apply the principles of thermodynamics but struggles with determining the heat transfer Q due to the absence of specific values for Cv and Cp. The conclusion emphasizes the need for additional data to accurately compute the internal energy change.

PREREQUISITES
  • Understanding of the Carnot cycle and its phases
  • Familiarity with thermodynamic equations, specifically ΔE=Q-W
  • Knowledge of isochoric and isobaric processes
  • Basic principles of gas laws and work calculations
NEXT STEPS
  • Research the specific heat capacities Cv and Cp for different gases
  • Study the derivation and application of the first law of thermodynamics
  • Learn about calculating work done in isochoric and isobaric processes
  • Explore the implications of Hess's law in thermodynamic cycles
USEFUL FOR

Students studying thermodynamics, particularly those working on problems related to the Carnot cycle, as well as educators and professionals seeking to deepen their understanding of internal energy changes in gases.

Munir M
Messages
12
Reaction score
0

Homework Statement


A gas is to be expanded from initial stage i to final stage f along either path 1 or path 2 on a p-V diagram. Path 1 consists of three steps: an isothermal expansion(work is 23J in magnitude), an adiabatic expansion(work is 35J in magnitude), and another isothermal expansion (work is 16J in magnitude). Path 2 consists of two steps: a pressure reduction at constant volume and an expansion at constant pressure. What is the change in the internal energy of the gas along path 2?

Homework Equations


ΔE=Q-W[/B]
W=nRTln(Vf/Vi)
W=∫PdV

The Attempt at a Solution


I added up the values from path 1 to be the work done, assuming that like a hess cycle the work done is same regardless of the path taken. I don't know how to get a value of Q as I don't know which equations out there work with isochoric and isobaric conditions.
 
Physics news on Phys.org
I found equations for isobaric and isochoric conditions. Q=nCpΔT and Q=nCvΔT. I still don't know how to solve it as none of the values for Cv and Cp are provided.
 

Similar threads

Efficiency of Stirling Cycle - Is it the same as the Carnot Engine?
  • · Replies 14 ·
Replies
14
Views
2K
Closed cycle of an ideal gas
  • · Replies 3 ·
Replies
3
Views
2K
Is the Use of C_V in Adiabatic Expansion of Carnot Cycle Incorrect?
  • · Replies 7 ·
Replies
7
Views
3K
Isothermal, isobaric and adiabatic
  • · Replies 6 ·
Replies
6
Views
2K
Undergrad Efficiency of cycles bounded by two isotherms
  • · Replies 5 ·
Replies
5
Views
3K
Corrected.Finding the Energy and Work in a Carnot Cycle
  • · Replies 7 ·
Replies
7
Views
2K
Carnot Engine cycle on PV Diagram
  • · Replies 5 ·
Replies
5
Views
2K
How does Carnot Cycle Expand and Compress Isentropically?
  • · Replies 5 ·
Replies
5
Views
2K
Carnot Cycle: Reversibility Under Constant External Pressure
  • · Replies 1 ·
Replies
1
Views
2K
The total work in a Carnot cycle - checking some work
  • · Replies 1 ·
Replies
1
Views
2K