Difference Between Gas and Liquid

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What are the Differences Between Gas and Liquid?

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All you see around you is made up of matter, like air, water, plants, clothing, and more. Matter refers to the set of particles that has mass and occupies space. The three fundamental states of matter are known as solid, liquid, and gas. Due to the differences between their molecules, there are multiple states of matter.

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The primary difference between liquid and gas is:

  • Liquids (substances that exist in the liquid state) don’t have any fixed shape and occupy a fixed volume. They are slightly compressible and take the shape of their containers.

  • Gases (substances that exist in the gaseous state) don’t have any fixed shape and don’t occupy any fixed volume. Gas substances are highly compressible and occupy the shape of their containers.


Gas is a state of matter in which the matter diffuses freely in all directions. Matter fills up the entire space available to them irrespective of the quantity of the gas. Gases do not have any definite volume and hence fill up the entire space available. Intermolecular forces in the gases are very weak which makes it easy for the matter to move freely. The particles of the gases do not have any specific shape and size. It is important to note that there is no specific volume or shape of materials in the gaseous state. The whole container volume is occupied by the gas. Besides, gas is extremely compressible and is considered to exert finite pressure on container walls.

Physical Characteristics of Gases

  • Gases have high kinetic energy.

  • Intermolecular forces between the gaseous particles are negligible.

  • Gases take the shapes and volume of the container.

  • Gaseous molecules exert pressure in all directions.


The liquid is a state of matter in which the matter has a fixed volume and no definite shape. The liquid takes up the shape of the container in which it is placed. The particles in the case of the liquid are having a stronger intermolecular force than the gas particles. The liquid always has a minimum surface area because of surface tension.

Liquids flow because intermolecular forces are weak enough between molecules to allow the molecules to move relative to another. The forces between the neighbouring molecules are intermolecular forces.

Liquids have some gas and solid properties at the molecular level. Both liquid and gas are fluid, which means that the intermolecular forces allow the molecules to move. In both the gas and liquid phase, the material does not have any fixed shape and instead takes up the shape of the container in which it is kept.

Physical Characteristics of Liquid

  • Liquids have fixed volume but no fixed shape.

  • Liquids have their boiling points above room temperature, under normal conditions.

  • Liquids are almost incompressible. In liquids, molecules are pretty close to each other.

Solved Examples

1. Can solid flows?

Ans: No, solids cannot flow as they have a rigid structure.


2. What is the composition of the gas we inhale?

Ans: In addition to oxygen, the air we breathe is made up of several other things! Just about 21 percent of air is made up of oxygen. The gas you breathe is known as nitrogen, about 78 percent. There are also very small amounts of other gases including argon, carbon dioxide, and methane.

Fun Facts

  • Pure gases are made up of just one atom. Neon is an example of pure gas.

  • Gas pressure is measured in pascals.

FAQ (Frequently Asked Questions)

1. Why is Carbon Dioxide a Gas?

Ans: Carbon dioxide is a molecular crystal, and the atoms are bonded together by a covalent bond. Carbon dioxide is made up of three-atom small molecules, each with a double bond to two-oxygen oxygen: O=C=O. In comparison, double bonds with silicone oxygen are unstable. As a result, silicon oxide forms a large network of alternating silicon and silicon oxide, each Si joined to 4 Oxygen and each O connected to 2 silicon atoms, rather than consisting of small molecules with double bonds. Given the difference in their chemical composition, carbon dioxide is solid as gas and silicon dioxide. Carbon dioxide is a circular structure that has two double bonds of carbon and oxygen. It is a small, nonpolar molecule with only slight molecular connections. It's a gas, therefore.

2. How do we Separate a Mixture of Gases with Different Molecular Weights?

Ans: The diffusion method is used to separate a mixture of gases having different molecular weights as the rate of diffusion varies inversely with molecular mass. This method is called atmolysis. The term atmolysis is defined as a method of separating gases depending on their differential rates of diffusion through a porous substance. A process of confining the mixture in a vessel with a porous material such as graphites into a vacuum to isolate the mixed gases or vapours with unequal diffusibility.