Determine the phase changes that carbon dioxide undergoes as the pressure changes if the temperature is held at −50°C? If the temperature is held at −40°C? At 20°C?

Let us determine the phase changes that \({\rm{C}}{{\rm{O}}_2}\)undergoes as the pressure changes if the temperature is −50°C

Here we can see that, if the temperature is constant \(\left( {{\rm{ - 5}}{{\rm{0}}^{\rm{^\circ }}}{\rm{C}}} \right){\rm{,C}}{{\rm{O}}_{\rm{2}}}\) will be:

- gaseous if the pressure is approximately 10-700 kPa

- liquid if the pressure is approximately\({\rm{700 - 200,000kPa}}\)

-solid if the pressure is higher than \({\rm{200,000kPa}}\)

If the temperature is constant \(\left( {{\rm{ - 4}}{{\rm{0}}^{\rm{^\circ }}}{\rm{C}}} \right){\rm{,C}}{{\rm{O}}_{\rm{2}}}\)will be:

- gaseous if the pressure is approximately 10-1000 kPa

- liquid if the pressure is approximately\({\rm{1000 - 400,000kPa}}\)

-solid if the pressure is higher than \({\rm{400,000kPa}}\)

If the temperature is constant at\(\left( {{\rm{2}}{{\rm{0}}^{\rm{^\circ }}}{\rm{C}}} \right){\rm{,C}}{{\rm{O}}_{\rm{2}}}\)will be:

-gaseous if the pressure is approximately 10-9000 kPa

-liquid if the pressure is approximately\(9000 - 900,000{\rm{kPa}}\)

-solid if the pressure is higher than \(900,000{\rm{kPa}}\)