liquid to gas is called evaporation but i don't know what gas to liquid is
When a gas is changed to a liquid the gas has condensed, or liquefied or cooled.
A liquid is any substance that maintains a constant volume, but not a constant shape, e.g., water.
Natural gas can be in either a gos or liquid form. To create a liquified natural gas, the natural gas needs to be filtered and cooled to -162 degrees C. This compresses the gas to 1/600th its...
Some gasses turn into liquids when compressed (propane, butane), some turn into liquids when chilled to very cold temperatures (oxygen, nitrogen).