The temperature at which a gas becomes liquid is called the condensation temperature. It is the temperature at which the vapor pressure of the gas is equal to the pressure of the surrounding atmosphere. At this temperature, the gas will begin to condense into a liquid.

The condensation temperature of a gas is dependent on several factors, including the type of gas, the pressure of the surrounding atmosphere, and the presence of any impurities in the gas. For example, the condensation temperature of water vapor is 100 degrees Celsius (212 degrees Fahrenheit) at sea level. However, the condensation temperature of water vapor will be higher at higher altitudes, where the atmospheric pressure is lower.

The condensation temperature of a gas can also be affected by the presence of impurities. For example, the presence of water vapor in air can lower the condensation temperature of other gases, such as carbon dioxide and methane.

The condensation temperature is an important concept in many fields of science and engineering, including meteorology, chemistry, and thermodynamics.