Molar specific heat capacities for gases

Click For Summary
SUMMARY

The discussion centers on the relationship between molar specific heat capacities for gases, specifically during an isochoric process where volume remains constant. It establishes that for such a process, the work done (dW) is zero, leading to the conclusion that the heat added (dQ) equals the change in internal energy (dU). The participants question the apparent contradiction between the derived equation Cp = Cv and the established relation Cp - Cv = R, highlighting the complexities of thermodynamic principles.

PREREQUISITES
  • Understanding of the First Law of Thermodynamics
  • Familiarity with molar heat capacities (Cp and Cv)
  • Knowledge of isochoric and isobaric processes
  • Basic principles of thermodynamics and gas laws
NEXT STEPS
  • Study the derivation of the First Law of Thermodynamics in detail
  • Explore the implications of Cp - Cv = R in various thermodynamic processes
  • Learn about isochoric and isobaric processes in real-world applications
  • Investigate the behavior of ideal gases under different thermodynamic conditions
USEFUL FOR

Students and professionals in physics and engineering, particularly those focusing on thermodynamics, heat transfer, and gas behavior in various processes.

saubhik
Messages
30
Reaction score
0
For an isochoric process,
dV = 0
therefore dW=0
So from 1st of Thermodynamics,
dQ = dU + 0
or, n*Cp*dT = n*Cv*dT (Cp and Cv denote molar heat capacities of the gas at const pressure and volume resp.)

therefore we get Cp = Cv .(how can this be possible once we know Cp - Cv = R ?)
 
Science news on Phys.org
If you are heating at constant volume, how does dQ=ncpdT?

If dQ=dU

and dU/dT = cv, then you'll just get Q= ncvΔT
 

Similar threads

Undergrad Question regarding dh, du, cp, cv for ideal gases
  • · Replies 3 ·
Replies
3
Views
2K
Undergrad Cannot understand formula for molar heat capacities of an ideal gas
  • · Replies 22 ·
Replies
22
Views
4K
Graduate Why is 0 K unattainable?
  • · Replies 11 ·
Replies
11
Views
1K
Graduate Question about the first law of thermodynamics
  • · Replies 3 ·
Replies
3
Views
2K
Undergrad Questions about my Understanding of Thermodynamics and Statistical Mechanics
  • · Replies 2 ·
Replies
2
Views
3K
Undergrad How to understand experiment to measure heat capacity of solid?
  • · Replies 1 ·
Replies
1
Views
2K
Undergrad Understanding the Molar Heat Capacity of an Ideal Gas
  • · Replies 1 ·
Replies
1
Views
1K
Graduate Molar Specific Heat (gas) at varying pressure and volume?
  • · Replies 5 ·
Replies
5
Views
2K
Undergrad I can’t understand the derivation of the formula Cp=Cv+nR
  • · Replies 4 ·
Replies
4
Views
16K
Undergrad Graphical difference between adiabatic and isothermal processes.
  • · Replies 1 ·
Replies
1
Views
4K