What occurs when a gas in a closed space is compressed?

When a gas in a closed space is compressed, its temperature increases due to the principles of thermodynamics. As the volume of the gas decreases, molecules are forced closer together, and their movements become more restricted. This leads to an increase in collisions between the gas molecules, which results in more kinetic energy. Since temperature is a measure of the average kinetic energy of the molecules, the increase in kinetic energy corresponds directly to an increase in temperature.

In addition to this, the process adheres to the ideal gas law, which demonstrates that if the volume is reduced while maintaining a constant amount of gas, the pressure must increase, which in turn causes the temperature to rise.

Understanding these concepts helps clarify why the other options don't apply: the gas cannot maintain a constant temperature (the second option) in a compression scenario because the energy increases due to work being done on the gas. The temperature cannot decrease (the first option) during compression, as this would contradict the increase in molecular activity. Lastly, evaporation typically refers to a phase transition from liquid to gas, which is not relevant in the context of compressing a gas in a closed space.