At what temperature can a person exhale white breath?

Below 10 degrees.

The process by which matter changes from gaseous to liquid state. Liquefaction is the reverse process of vaporization. Gas molecules attract each other and condense into liquid. Substances release heat when they liquefy. Any gas below the critical temperature can be liquefied. Liquefaction can be achieved by pressurization or cooling, or a combination of pressurization and cooling. Gases whose critical temperature is higher than or close to room temperature, such as ether, chlorine, ammonia, sulfur dioxide, carbon dioxide and certain hydrocarbons, can be liquefied by compression at room temperature. Gases with very low critical temperatures, such as oxygen, nitrogen, hydrogen, helium, etc., must first be cooled below their critical temperatures and then liquefied by isothermal compression.

Extended information:

Two ways of liquefaction: lowering the temperature (all temperatures of all gases) and compressing the volume (some gases have a certain temperature ), any gas can liquefy when its temperature drops low enough.

Heat release of liquefaction

1. Burns from 100°C water vapor are often much more serious than burns from 100°C boiling water - water vapor releases a lot of heat when it liquefies.

2. Breathing on the hands in winter - the water vapor in the mouth liquefies and releases heat to warm the hands (this method is not as good as rubbing the hands to warm the hands. After liquefaction, small water droplets will appear on the hands. , small water droplets will absorb heat when they evaporate (vaporize)).

Baidu Encyclopedia - Liquefaction

Baidu Encyclopedia - Liquefaction