The following steps occur sequentially when a gas cools down and become liquid.
1. Particles of gas move slower
2.The gas loses thermal energy.
3.The spaces between the gas particles decreases.
4. The gas changes to liquid.
The particles of gases are typically far apart and they move about randomly colliding with one another and with the wall of the container in which the gas is enclosed. When a gas is been cool down, the particles of the gas will lose kinetic energy and their movement will become slower, thus, they will lose thermal energy and the spaces between them will become reduced. As the cooling continues, the gas will eventually change to liquid.
