Question

1.Refer to the phase diagram for carbon dioxide in Figure 11.12.

Explain, in terms of the triple point, whether or not CO₂ can be a liquid at 2.0 atm.

Determine what phase CO₂ will have at 2.0 atm and − 78 ^oC.

Determine the new phase if CO₂ is kept at 2.0 atm while warmed to 0 ^oC.

Finally, determine the phase again if CO₂ is kept at 0 ^oC, but pressurized to 72 atm.    

Answer each part with a complete sentence.  

Answer 1

Referring to the phase diagram for CO2,

At 2.0 atm pressure, CO2 can either be in solid phase or can be in gas phase, it cannot exist as a liquid.

At 2.0 atm pressure and a temperature of -78 oC, CO2 will exist only in solid phase.

If CO2 at an initial pressure of 2.0 atm is warmed to 0 oC, the solid CO2 will slowly get converted into liquid CO2 phase.

Once again, If CO2 is kept at a constant temperature of 0 oC and pressurised to 72 atm, the new phase of system would be liquid CO2 phase.