In science, matter is anything which occupies space and which has mass. There are three states of matter; solid, liquid, and gas.
All three states of matter are important for the environment in one or the other form. Gas is also considered a state of matter. Although it is not visible, it still occupies space and has some volume and mass.
Although several things are not categorized under the three States of matter, their existence is still important.
With the temperature change, the three states of matter can interchange themselves; for example, solid ice can turn into water that is liquid and by getting heated up it can change into gas as well.
Key Takeaways
- Vapor is a gaseous substance generated by the evaporation or boiling of a liquid, while gas is a state of matter that exists naturally in the atmosphere.
- Vapor can be seen and felt as a mist or fog, while gas is invisible to the naked eye.
- Vapor can be easily condensed back into a liquid state, while gas requires high pressure or low temperature to become a liquid.
Vapour vs Gas
The difference between vapour and gas is that vapour is not a gaseous state of matter, it can be solid or liquid, but gas is a gaseous state of matter. Although, they might seem confusing as both of them are in a gaseous state.
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Comparison Table
Parameters of Comparison | Vapor | Gas |
---|---|---|
Definition | State of transition from liquid to gas, which is formed by boiling a liquid (this process is also known as evaporation). | One of the three states of matter is made up of elemental or compound molecules, like air, which contains several pure gases. |
Inclusion in State of Matter | Not included | Included |
Formation | Forms when at temperatures below the boiling point of water. | Forms when above its critical temperature. |
Shape under microscope | It has a definite shape | It does not have a definite shape |
Examples | Chemicals in perfumes, mist, etc. | Air, oxygen, carbon dioxide, etc. |
What is Vapor?
Vapor is the state of transition from liquid to gas, formed by boiling a liquid (this process is also known as evaporation). Vapor is different from aerosol.
Under the microscope, vapour has a definite shape; It consists of molecules which move randomly in any direction. The state of equilibrium is maintained when vapour is in contact with the liquid or solid phase.
In the procedure of cloud formation and condensation, the vapor is responsible.
Since vapor is in the gas phase, it is measurable and obeys the barometric formula in the gravitational field.
The vapor pressure is the equilibrium pressure from a liquid or a solid at a specific temperature. It can be seen with the help of graphs.
At the normal boiling point, the vapor pressure equals the normal atmospheric pressure.
Examples of vapor are; atmospheric water vapor, found near the earth’s surface and may condense in the form of small liquid droplets in the form of fog or mist.
Perfumes contain several chemicals which vaporize at different temperatures; mercury vapor lamps are available, etc.
Vapor is the result of any process of boiling or evaporation through the vaporization of any liquid; the transitional phase contains vapor. Evaporation and boiling of any liquid occur when its boiling temperature is at a given pressure.
What is Gas?
Gas is one of the three states of matter; it comprises elemental or compound molecules, like air, which contains several pure gases.
Gases have low density, meaning they have great space between molecules with a lot of kinetic energy.
Natural gas contains methane, a compound with one carbon atom and four hydrogen atoms; it contains vapor, non-hydrocarbon gases and some amount of natural gas liquids.
Some elemental gases are; hydrogen, nitrogen, fluorine, helium, oxygen, argon, neon, etc.
Gases are difficult to observe with the naked, but it can be felt like air is always present in the atmosphere (vacuum is an exceptional case ); oxygen and carbon dioxide are important gases in the human respiratory system, but they cannot be seen easily.
Some gases have an odour. Thus, they can be smelled easily.
Gases are easy to compress due to low density and occupy larger space than any solid or liquid. Gases also have infusibility properties, and they have no definite shape.
Gases can be compressed and stored easily when too much pressure is exerted on gases. They even formulate in some liquids.
A few examples of gases are; air, ammonia, carbon dioxide, carbon monoxide, hexane, methanol, methane, nitrogen, neon, helium, oxygen, etc. Some toxic gases are; chlorine, arsine, bromine, germane, phosphine, etc.
Main Differences Between Vapor and Gas
- Vapor is the state of transition from liquid to gas, formed by boiling a liquid; on the other hand, gas is one of the three states of matter, made up of elemental molecules or compound molecules, like air, which contains several pure gases.
- Vapor is a definite shape under microscopic observation; however, gas has no definite shape.
- Vapor is a gaseous phase but not considered a state of matter gas is one of the three states of matter.
- The vapor of water is always present in the environment at temperatures below the boiling point of water; on the other hand, gas forms above its critical temperature.
- Some examples of vapor are; fog, mist, chemicals in perfumes, mercury vapor lamps, etc.; on the other hand, a few examples of gas are; air, oxygen, carbon dioxide, methane, etc.
References
- https://aip.scitation.org/doi/pdf/10.1063/1.1753975%40apl.2019.APLCLASS2019.issue-1
- https://link.springer.com/article/10.1557/JMR.1986.0205
Piyush Yadav has spent the past 25 years working as a physicist in the local community. He is a physicist passionate about making science more accessible to our readers. He holds a BSc in Natural Sciences and Post Graduate Diploma in Environmental Science. You can read more about him on his bio page.