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Question
Answer the following question based on the P-T phase diagram of carbon dioxide:
Is CO2 solid, liquid or gas at
- –70 °C under 1 atm,
- –60 °C under 10 atm,
- 15 °C under 56 atm?
Solution 1
It can be concluded from the P-T phase diagram of CO2 that:
- CO2 is gaseous at –70°C, under 1 atm pressure
- CO2 is solid at –60°C, under 10 atm pressure
- CO2 is liquid at 15°C, under 56 atm pressure
Solution 2
- The point (- 70 °C, 1.0 atm) lies in the vapour region. Hence, CO2 is vapour at this point.
- The point (- 60 °C, 10 atm) lies in the solid region. Hence, CO2 is solid at this point.
- The point (15 °C, 56 atm) lies in the liquid region. Hence, CO2 is liquid at this point
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