The specific heat capacity at constant pressure, often denoted as Cp, is a thermodynamic property that measures the amount of heat energy required to raise the temperature of a substance while keeping the pressure constant. It quantifies how a substance’s temperature changes when heat is added at a constant pressure. The formula for specific heat capacity at constant pressure is as follows:
- γ (gamma) is the ratio of specific heat capacities, where γ = Cp / Cv. Cp is the specific heat capacity at constant pressure, and Cv is the specific heat capacity at constant volume.
- R is the specific gas constant, which is specific to the type of gas you are dealing with. For example, for dry air, R is approximately 287 J/(kg·K).
- (γ – 1) represents the difference between the adiabatic index and 1.
The specific heat capacity at constant pressure (Cp) is related to the specific heat capacity at constant volume (Cv) and the gas constant (R) for an ideal gas by the equation Cp – Cv = R. This equation describes how the heat capacity of an ideal gas changes at constant pressure compared to constant volume.
So, in summary, Cp = γR / (γ – 1) is an expression used to calculate the specific heat capacity at constant pressure for an ideal gas.