There are two ways to liquefy a gas:
-- Increase the pressure on it.
-- Lower its temperature.
The liquefication is faster and easier if you do both.
Two ways to liquefy gases are by increasing pressure and lowering temperature. Increasing pressure compacts the gas molecules, allowing intermolecular forces to take effect, while lowering the temperature decreases kinetic energy. Combining both methods can more effectively lead to liquefaction.
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