At room temperature (25°C) and pressure (1 atm), ammonia is a gas. This is because it has a relatively weak intermolecular force of attraction between ammonia molecules, which allows it to move more freely and expand to fill its container. However, ammonia can also be liquefied by increasing its pressure or decreasing its temperature. When the temperature of ammonia is decreased to below its boiling point (-33.34°C) at 1 atm, it condenses into a liquid state. Alternatively, when the pressure of ammonia is increased above its critical pressure (112.8 atm) at any temperature, it also liquefies.