Air is a mixture of gases and contains various pollutants . The gases are useful and can be seperated by fractional distillation of liquid air . The table gives information about some of the gases in air
to seperate these gases :
the air is filtered
water is removed first
carbon dioixde is then removed by absorption
the gases remaining are compressed and cooled to -200°C
Water vapour and carbon dioxide are removed before the gases are compressed andcooled.Use the information in the table to suggest why.