Molar heat capacity at constant volume for air from 67 to 300 K at pressures to 35 MPa

Measurements of the molar heat capacity at constant volumeC v for air were conducted with an adiabatic calorimeter. Temperatures ranged from 67 to 300 K, and pressures ranged up to 35 MPa. Measurements were conducted at 17 densities which ranged from gas to highly compressed liquid states. In total, 227C v values were obtained. The air sample was prepared gravimetrically from research purity gases resulting in a mole fraction composition of 0.78112 N2 + 0.20966 O2 + 0.00922 Ar. The primary sources of uncertainty are the estimated temperature rise and the estimated quantity of substance in the calorimeter. Overall, the uncertainty (± 2σ) of theC v values is estimated to be less than ± 2% for the gas and ±0.5% for the liquid.