Carbon Dioxide Properties

Overview

Engineering reference data for Carbon Dioxide Properties in gases and compressed air.

Key Formulas

Ideal Gas Law

$PV = nRT$

Pressure × Volume = moles × gas constant × temperature.

Boyle's Law

$P_1 V_1 = P_2 V_2$

At constant temperature.

Charles's Law

$\frac{V_1}{T_1} = \frac{V_2}{T_2}$

At constant pressure.

Variables

Symbol	Description	Unit
$P$	Pressure	Pa
$V$	Volume	m³
$T$	Temperature	K
$R$	Gas constant	8.314 J/(mol·K)

Key Thermodynamic Properties

The enthalpy ($H$), entropy ($S$), and internal energy ($U$) are fundamental state functions for carbon dioxide.

For an ideal gas, these are related by: $H = U + pV = U + nRT$

The change in enthalpy with temperature at constant pressure is the heat capacity: $\left( \frac{\partial H}{\partial T} \right)_p = C_p$

The change in entropy with temperature at constant pressure is: $\left( \frac{\partial S}{\partial T} \right)_p = \frac{C_p}{T}$

Additional Thermodynamic Formulas

A useful relation for enthalpy change: $\Delta H = \int_{T_1}^{T_2} C_p \, dT$

For entropy change between two states: $\Delta S = \int_{T_1}^{T_2} \frac{C_p}{T} \, dT - R \ln\left(\frac{p_2}{p_1}\right)$

The heat capacity ratio ($\gamma$) is important for adiabatic processes: $\gamma = \frac{C_p}{C_v}$

Physical Properties

The critical properties of carbon dioxide ($CO_2$) are essential for equations of state:

• Molecular Weight: 44.01 g/mol
• Critical Temperature ($T_c$): 304.25 K (31.10 °C)
• Critical Pressure ($P_c$): 7.39 MPa (73.9 bar)
• Specific Heat at Constant Pressure ($C_p$, 25°C): 0.844 kJ/kg·K

References

• Original Source