How do you change liquid to gas?

Answer 1

To change the phase of a system from liquid to gas, the total system energy must be increased (heat added) to the point where every atom or molecule has sufficient energy to escape the liquid system.

Answer 2

Liquid changes to gas through a process called evaporation, where the molecules in the liquid gain enough energy to overcome the intermolecular forces holding them together. This causes the liquid to turn into vapor and transition to the gaseous state.