How do you convert gas to liquid?

Question

How do you convert gas to liquid?

Answer 1

cooling it or pressurized it

Answer 2

The state that matter exists in (solid, liquid, or gas) is summarized by what's called a "phase diagram". Think of it as kind of a map of where the different states of a pure substance exist, except the two "directions" (axes) are pressure and temperature.

If you're not changing the pressure, as would be the case if stuff were just sitting out, the only way you can move on the map is to higher or lower temperature. Usually to convert a gas to a liquid just means that you move to lower temperatures.

But that doesn't always work. Some substances don't have a liquid state at normal pressures, so when you move down the temperature axis, you go directly from gas to solid. Carbon dioxide, the gas in the atmosphere that we and burning fuel put out and plants take in, is one such substance. Carbon dioxide goes directly from a solid ("dry ice") to a gas.

To make liquid carbon dioxide, you need to not only move down the temperature axis, but up the pressure axis as well. Then as its phase diagram shows, you are in the region of liquid carbon dixide. For example, at 20 degrees C under a pressure of 56.3 atmospheres, carbon dioxide is a liquid, and that's how it exists in carbon dioxide fire extinguishers.

When you use one of those fire extinguishers, you see a stream of carbon dixoxide "snow", the solid form. That's because as the liquid form evaporates, it cools down the gas, but now it's at normal atmospheric pressure so the gas goes directly into the splid state. You can follow this process on the phase diagram.

So, the bottom line: you can make a gas turn into a liquid by the right combination of temperature and pressure, but sometimes you have to tweak both. Generally, you want lower temperature (the molecules become less active and clump together) and/or high pressure (you shove them together).

Answer 3

The other answers are fine but I thought I'd give another dimension to your question.

The reason why gases change state to a liquid is that by whatever means the particles (atoms and/or molecules) get close enough for the dispersion forces to become important. This allows the formation of surface tension to droplets that coalesce into the form we call liquid.

The ways that we get the particles close enough for dispersion forces to become significant can be accomplished by increasing the pressure, which is nothing more than forcing the particles into a smaller volume - thus closer to each other. Or you can decrease the temperature by absorbing the thermal kinetic energy, slowing down the particles and allowing the dispersion forces to become more significant.

You can also make a liquid state more probable by applying strong magnetic forces to either paramagnetic or even magnetic particles. But most people don't use those means because they take more energy.

In general anything that would increase the dispersion forces, will help in moving from a gaseous to a liquid state.

Dispersion forces include: dipole-dipole forces, van der Waal forces, and hydrogen bonding. I'm sure there are others that I've forgotten.

Answer 4

Well, water vapor condenses to water by trapping it and with use of air to cool the vapor down and thus converts it to water. Look at the condensation curve of a gas. I think it is call the triple point curve of the 3 matters (not for sure--search it up). The states of the matter is affected by the change in pressure and temperature,; thus by altering these two factors, you can change the states of a matter!

Answer 5

The best mean is to cool the gas so to decrease the temperature.
An other possibility at constant temperature is to increase the pressure of the gas

Answer 6

Cool the gas.

Answer 7

Take the termperature right down or compress the gas I think.

Answer 8

i JUST did this experiment like yesterday!! you cool it! like when u boil water it turns to steam....u cool it back down to turn it back to water :)

Answer 9

remove energy. cool it