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Difference Between Vapor and Gas for JEE Main 2024

Last updated date: 09th Apr 2024
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Introduction - Vapor and Gas

Anything that takes up space and has a lot of weight is called "matter."

Matter exists in three main states, solid, liquid, and gas. Solids have a definite shape and volume (for example Ice). Liquids, like water, have a defined volume but can change their shape depending upon the container. 

Everyone needs one or more of the three states of matter in some way. Gas is also a state of matter, even though it isn't visible, it takes up space and has some volume and mass. The gaseous state has neither definite shape nor volume. An example of gas is oxygen, carbon dioxide, and water vapor. 


A substance in its gaseous phase is referred to as a vapor in physics.

It has a lower temperature than the critical temperature. When the pressure is increased without raising the temperature, the vapor can condense and become a liquid.

However, a vapor can always be confused by an aerosol but it should be noted that it is not the same as an aerosol. An aerosol is a gas that contains both liquid and solid elements.

Ironically a large component of the earth’s atmosphere is made of water vapor compared to other greenhouse gases. The water vapor content in the atmosphere is variable and so difficult to measure. 


  • Vapor refers to the gas phase below the crucial temperature where either a solid or a liquid can exist at the same time.

  • When the vapor is close to either the solid or liquid phase, both phases come to a state of equilibrium.

  • The term "gas" refers to a fluid phase that can be easily squeezed.

  • The condensation of vapor is associated with the production of clouds.

  • Vapor molecules move in three directions: rotationally, translationally, and vibrationally.

  • Water vapor emits and absorbs infrared radiation at many more wavelengths than other greenhouse gases and accounts for the largest greenhouse effect. 

Vapor Pressure

The equilibrium pressure exerted by solids or liquids at a certain temperature is known as vapor pressure.

The vapor pressure is described by Raoult's law, which states that every component's partial pressure is equal to the product of the pure component's vapor pressure and the mole fraction of the mixture.

Atmospheric water vapor, which is present near the earth's surface and can condense into minute liquid droplets in the form of fog or mist, is an example of vapor.

Perfumes contain a variety of compounds that vaporize at different temperatures etc is an example too.

Measuring Vapor

Because it is in the gaseous state, the partial pressure of the gas is used to calculate the amount of vapor present. In a gravitational field, vapors, like normal atmospheric gases, obey the barometer formula.


The gas is classified as one of the four states of matter; they have the distinct features of occupying the available space regardless of the shape and volume. This feature is because of the presence of very little intermolecular attraction between the molecules. The other three states of matter are solid, liquid and plasma. The substances that exist in a gaseous form have neither a specific shape nor a specific volume. When they're encased in a container, they take up the entire space. They then exert a little pressure on the container walls.

The intermolecular distances in gases are enormous and may readily be compressed. The attractive forces that exist between the gas particles are small.

So, the gas can fill out the container of any size as the gaseous molecules are constantly on the move. The compounds which even remain in the gaseous state are classified as gas. For example, carbon dioxide is classified as gas, that is because it remains gas even at room temperature. 

Some gases cannot form solid or liquid at any temperature and are called fixed gases. The molecules in a gas are vastly separated and hence, gases are invisible to the naked eye. 

Air, ammonia, carbon dioxide, carbon monoxide, hexane, methanol, methane, nitrogen, neon, helium, oxygen, etc are examples of gases. Chlorine, arsine, bromine, germane, phosphine, come under poisonous gases.


  • Gases have a lower density and are highly compressible when compared to solids and liquids.

  • All of the gaseous particles exert the same amount of pressure on the wall's surfaces.

  • Gases have high kinetic energy. And the distance between each gas particle is considerable.

  • The intermolecular forces that exist between gas molecules are considered negligible.

  • Gases take up the entire volume of any container in which they are placed. The particles of gas move in all directions and collide with one another.

Macroscopic Gas View

The frame of reference or length scale for monitoring a gas is common. From a macroscopic or global perspective, a longer length scale is needed.

Gas characteristics are measured macroscopically in terms of gas-particle velocity, pressure, and temperature or volume. One of his tests related pressure and volume of a gas. His test used a J-tube manometer, which is a test tube shaped like the letter J. Boyle used a mercury column to trap an inert gas in the test tube's closed-end, keeping the particle count and temperature constant. 

His observation concluded that Increasing the gas pressure by adding more mercury to the column reduced the trapped gas volume (this is known as an inverse relationship). Boyle's multiplication of pressure and volume for each observation came to be constant. This link held for all gases Boyle observed, leading to the law (PV=k) named after him.

Microscopic Gas View

Under a strong microscope, a gas would appear to be a collection of particles with no clear shape or volume moving in a more or less random manner. When these gas particles collide with another particle or the container's sides, they shift direction.

The List of Some Gases (At Standard Conditions) is Provided Below Along with the Formula.  

  • Hydrogen (H2)

  • Nitrogen (N2)

  • Carbon monoxide (CO)

  • Fluorine (F2)

  • Argon (Ar)

  • Oxygen (O2)

  • Methane (CH4)

Difference Between Vapor and Gas



It's usually a combination of two stages that exist at the same time and at the same temperature. Both the gaseous and liquid phases contain these phases.

At the current room temperature, the state of matter in gases is single.

They are made up of random atoms. There are also molecules that travel in all directions.

Gases are made up of a random collection of atoms and molecules that travel in every direction.

Vapor, unlike gases, is not classified as a state of matter.

Gas is one of the states of matter.

Water vapors surround us at all times while the temperature is below the boiling point.

The creation of gases takes place at temperatures above critical, but at pressures below critical.

Under microscopic examination, vapor has a distinct shape.

Under microscopic examination, gas has no discernible shape.