When a gas gets cold, what does it become? A solid or liquid?
IT IS A LIQUID
Most become liquid first, but some (like CO2) become a solid without becoming a liquid first. What happens also depends upon what the pressure is.
When a gas gets cold, it can become either a liquid or a solid, depending on the specific gas and the temperature at which it is cooled. This transformation from gas to liquid or solid is known as condensation.
To determine which state a gas will transition into when it gets cold, you need to understand the concept of the "phase diagram" for that particular gas. A phase diagram is a graphical representation that illustrates the different phases of matter (solid, liquid, and gas) as they relate to changes in temperature and pressure.
In general, when a gas is cooled, its particles lose energy and slow down. If the temperature drops below the gas's "condensation point" (also known as its "boiling point" or "melting point"), the gas will transition into a different state.
For example, if you consider water vapor, which is a gas, when it gets cold, it turns into a liquid. The condensation point of water vapor is 100 degrees Celsius (212 degrees Fahrenheit) at atmospheric pressure. So, when water vapor is cooled below this temperature, it will condense and transform into liquid water.
On the other hand, certain gases, such as carbon dioxide, can directly transition from a gas to a solid through a process called "deposition." This occurs at temperatures below the gas's "sublimation point," where the gas turns directly into a solid without going through the liquid state. The sublimation point of carbon dioxide is around -78 degrees Celsius (-108 degrees Fahrenheit) at atmospheric pressure. So, when carbon dioxide gas is cooled below this temperature, it will undergo deposition and change into solid carbon dioxide, commonly known as dry ice.
In summary, the state that a gas will change into when it gets cold depends on the specific gas and its condensation or sublimation point. By referring to the phase diagram or researching the properties of the gas, you can determine whether it will become a liquid or a solid when it cools.