Cp & Cv Values: Example Problem 11.1 Explained

In summary, the conversation is discussing the calculation of cp and cv for an ideal gas. The formula for cp is mentioned as Q=m*cp*delta T and for cv as Q=n*cv*delta T. The solution given shows the calculation for cp and cv using the ideal gas constant and the number of degrees of freedom. The question is then asked about how these numbers were obtained and the relationship between cp and cv.
  • #1
williamcarter
153
4
Hello, I tried attempting the following example problem 11.1(please see below), however I don't quite get from where they got cp=1.00 and cv=0.717?
I know that Q=m*cp*delta T=> cp=Q/(m*delta T)
Q=n*cv*delta T=>cv=Q/(n*deltaT)

Problem statement
Capture.PNG
Their solution:
Capture2.PNG


How did they manage to get for cp=1.00 and cv=0.717?

Thank you
 
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  • #2
(3.5)(8.314)/29=1.00
 
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  • #3
Chestermiller said:
(3.5)(8.314)/29=1.00
Thank you , but how did you get these numbers from? They are not given in the statement of the problem.
What about cv?
 
  • #4
In terms of the ideal gas constant R and the number of degrees of freedom f, what is the equation for the molar heat capacity at constant volume of an ideal gas? In terms of the ideal gas constant R, what is the relationship between the molar heat capacity at constant pressure and the molar heat capacity at constant volume of an ideal gas?
 
Last edited:

What are Cp and Cv values?

Cp and Cv values are thermodynamic properties that represent the specific heat capacity at constant pressure and constant volume, respectively. They are used to calculate the amount of heat required to raise the temperature of a substance, and they differ because of the different ways that heat is transferred at constant pressure and constant volume.

Why are Cp and Cv values important?

Cp and Cv values are important because they help us understand the behavior of materials at different temperatures and pressures. They are also used in various engineering and scientific applications, such as in the design of engines and in the study of thermodynamic processes.

How are Cp and Cv values measured?

Cp and Cv values are typically measured experimentally using specialized equipment such as calorimeters. These measurements can also be calculated using theoretical models based on the material's composition and properties.

What is an example of using Cp and Cv values in problem solving?

An example problem using Cp and Cv values could involve calculating the amount of heat required to raise the temperature of a gas from a given initial temperature to a final temperature, while also taking into account changes in pressure and volume. This type of problem is commonly encountered in thermodynamics and heat transfer applications.

What factors can affect the Cp and Cv values of a substance?

Cp and Cv values can be affected by various factors, such as the molecular structure and composition of the substance, temperature, and pressure. In some cases, the Cp and Cv values may also vary with changes in volume or with the presence of other substances in the system.

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