Which phase change occurs when a gas becomes a liquid?

The phase change that occurs when a gas becomes a liquid is known as condensation. This process takes place when the temperature of the gas decreases or when it comes into contact with a cooler surface, leading to a loss of energy. As the gas cools, its molecules slow down and come closer together, transitioning from a gaseous state to a liquid state. This is a common occurrence in everyday life; for example, when water vapor in the air comes into contact with a cold surface, like a glass of ice water, it condenses and forms droplets of liquid water on the outside of the glass.