critical pressure and temperature

[ameer]

What is the critical pressure and temperature? and how i can detrmine it ? can any one give me brief notes

[Foad]

The critical temperature of a substance is the temperature at and above which vapor of the substance cannot be liquefied, no matter how much pressure is applied.

Every substance has a critical temperature. For ex..
NH3 132 C
O2 -119
CO2 31.2
H2O 374

critical pressure of a substance is the pressure required to liquefy a gas at its critical temperature.
For examples the critical pressure of a bove substance

NH3 111.5 (atm)
O2 49.7
CO2 73.0
H2O 217.7

[ivan_aljeburi]

If you have a mixture of gases, you will have to calculate the precentage of every component...

Tc=SUM of Tci times the precentage of that component

Pc= SUM of Pci times the precentage of that component