With carbon dioxide, what phase change takes place when pressure increases from 1 atm to 10 atm at -40C?

See explanation

Explanation:

The phase changes of carbon dioxide is quite interesting. It is even more interesting that its phase change from gas to solid is dependent on pressure and temperature.

The triple point of CO2 is -56°C at 5.11 atm pressure. This implies that below 5.11 atm, liquid CO2 can not exist. In fact, at -78°C and 1 atm, CO2 is a solid.

Hence, when pressure increases from 1 atm to 10 atm at -40C, CO2 changes from liquid to gas.