Discussion Overview
The discussion revolves around the calculation of the specific heat at constant volume (Cv) for air, particularly in relation to changes in temperature. Participants explore the relationship between Cv and the specific heat at constant pressure (Cp), and the potential need for an equation to facilitate calculations in a spreadsheet.
Discussion Character
- Technical explanation
- Mathematical reasoning
- Homework-related
Main Points Raised
- Gordon requests an equation to calculate Cv as a function of temperature, similar to the provided equation for Cp.
- One participant suggests looking up the equation for the specific substance in a reference table, such as Perry's Chemical Engineering Handbook, and mentions the relationship between Cp and Cv for ideal gases.
- Gordon clarifies that the gas in question is air and notes that Cv can be derived from Cp by subtracting the ideal gas constant (R).
- Another participant questions the assumptions regarding the constancy of Cv, Cp, and R with respect to temperature under the specified conditions.
- A participant confirms the relationship Cp = Cv + R.
- One participant offers a spreadsheet output that provides Cv and Cp values at various pressures and temperatures, suggesting a curve fitting approach.
- Gordon inquires about the underlying equation for the values provided in the spreadsheet.
Areas of Agreement / Disagreement
Participants express differing views on the constancy of Cv, Cp, and R with temperature, indicating that the discussion remains unresolved regarding the assumptions made in the original question.
Contextual Notes
There are limitations regarding the assumptions about the behavior of air under various conditions, including temperature and pressure, which may affect the applicability of the relationships discussed.
Who May Find This Useful
This discussion may be useful for individuals interested in thermodynamics, specifically those working with specific heat calculations for gases, as well as those looking for practical applications in spreadsheet modeling.