Enter the heat capacity at constant pressure (J/K) and the heat capacity at constant volume (J/K) into the Calculator. The calculator will evaluate the Heat Capacity Ratio. 

Heat Capacity Ratio Formula

HCR = Cp / Cv

Variables:

  • HCR is the Heat Capacity Ratio ()
  • Cp is the heat capacity at constant pressure (J/K)
  • Cv is the heat capacity at constant volume (J/K)

To calculate Heat Capacity Ratio, divide the heat capacity at constant pressure by the heat capacity at constant volume.

How to Calculate Heat Capacity Ratio?

The following steps outline how to calculate the Heat Capacity Ratio.


  1. First, determine the heat capacity at constant pressure (J/K). 
  2. Next, determine the heat capacity at constant volume (J/K). 
  3. Next, gather the formula from above = HCR = Cp / Cv.
  4. Finally, calculate the Heat Capacity Ratio.
  5. After inserting the variables and calculating the result, check your answer with the calculator above.

Example Problem : 

Use the following variables as an example problem to test your knowledge.

heat capacity at constant pressure (J/K) = 50

heat capacity at constant volume (J/K) = 20

Frequently Asked Questions

What is the significance of the Heat Capacity Ratio (HCR)?

The Heat Capacity Ratio is crucial in thermodynamics and fluid mechanics as it affects the speed of sound in gases, the performance of heat engines, and the efficiency of refrigeration cycles. A higher HCR indicates a gas that is more adiabatic, meaning it can do more work in a thermodynamic cycle.

Why do Cp and Cv have different values?

Cp (heat capacity at constant pressure) and Cv (heat capacity at constant volume) have different values because adding heat at constant pressure allows for expansion work, requiring more energy to raise the temperature by the same amount compared to a system at constant volume where no work is done.

Can the Heat Capacity Ratio vary with temperature?

Yes, the Heat Capacity Ratio can vary with temperature, especially for real gases. For ideal gases, the ratio is considered constant over a wide temperature range. However, for real gases, variations in molecular interactions at different temperatures can affect both Cp and Cv, thereby changing the HCR.

How is the Heat Capacity Ratio related to gas dynamics?

In gas dynamics, the Heat Capacity Ratio plays a pivotal role in determining the Mach number, which is a measure of speed relative to the speed of sound. The HCR influences the speed of sound in a gas, and thus, changes in the HCR can affect the flow characteristics of gases moving at high speeds.