# CO2 Phase Diagrams

Help yourself to learn the phase of the carbon dioxide using these free and printable CO2 phase diagrams! These printable phase diagrams are designed to guide you in studying the phase of CO2. In the following images, the phase diagrams of CO2 are provided in detail. A phase diagram is a diagram showing the various phases of a system. Phase diagrams for a pure compound such as phase diagrams for water and carbon dioxide are phase diagrams for a single component system. Take a look at the following CO2 diagram chart below.

In these CO2 phase diagrams, pressure (P) and temperature (T) are usually the coordinates. The phase diagrams usually show the (P, T) conditions for stable phases. The phase diagram of CO2 has some common features with that of water: sublimation curve, vaporization curve, triple point, critical temperature and pressure. Of course, the P and T values of are unique to carbon dioxide. In the following phase diagrams, shown that the triple point of carbon dioxide occure at a pressure of 5.2 atm (3952 torr) and 216.6 K (-56.4oC). At temperature of 197.5 K (-78.5oC), the vapor pressure of solid carbon dioxide is 1 atm (760 torr). At this pressure, the liquid phase is not stable, the solid simply sublimates. Thus solid carbon dioxide is called dry ice, because it does not go through a liquid state in its phase transition at room pressure. The critical temperature for carbon dioxide is 31.1°C, and the critical pressure is 73 atm. Above the critical temperature, the fluid is called super-critical fluid.

The only thing special about this phase diagram is the position of the triple point which is well above atmospheric pressure. It is impossible to get any liquid carbon dioxide at pressures less than 5.11 atmospheres. That means that at 1 atmosphere pressure, carbon dioxide will sublime at a temperature of -78°C. This is the reason that solid carbon dioxide is often known as “dry ice”. You can’t get liquid carbon dioxide under normal conditions – only the solid or the vapour.

Get all these diagrams as your teaching or learning resources in studying about the carbon dioxide phase diagrams. More educational and resourceful diagrams are also available in the other posts in this site!