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# Why Solids, Liquids and Gases Have Different Properties

Whenever we look around we see different substances variant to each other on the basis of their shape, structure, volume, etc. If we look into examples, oils are present in a liquid state, stones in solid, and air is present in gaseous form.

We also observe various substances changing their state under the influence of thermal energy, pressure, or any other factor. As a solid ice cube gets melted into water and forms liquid and when sufficient heat is provided to water it changes in gas as vapor. These different states of substances, as well as their state change, is due to various physical properties of them such as intermolecular force, the distance between particles, compressibility, etc which are responsible to determine the state of a matter.

The article below is focused on the different states of matter and their physical properties that determine their state. As well as it has also discussed why solids, liquids, and gases have different properties.

### What is the matter?

We come across many substances like a small pebble to high mountains, these all substances are made up of tiny particles that have their own mass and occupy certain space. This is matter, everything in the existing world is made up of particles having space and volume like rocks, sand, households to everything we see around.

The matter is defined as a substance that has mass and occupies a certain space or has volume.

### What are Solids?

The solid is a state of matter that has a fixed shape and definite volume. It has a rigid structure hence does not takes the shape of the container, unlike liquid or gases. The solids have tightly packed molecules as a result have high intermolecular force. As the molecules are tightly packed they do not flow and acquires high density.

Solids show the least expansion as compared to other states of matter due to their rigid nature. They cannot be compressed easily under normal conditions. Whereas, some of their states can be changed into a liquid with an increase in temperature.

Some of the examples of solid are sugar, salt, sand, stone, wood, etc.

Properties of Solids

• Solids have high inter-molecular force.
• Solids have fixed shapes and volumes.
• Solid cannot be compressed too much.
• They have really high density and are heavy in nature.
• As the molecules of solids are highly packed so they do not flow.
• Most of the solids are rigid in nature. Hence, their shape cannot be changed easily but can be broken down under the influence of force.

### What are Liquids?

The liquid is a state of matter that does not have a fixed shape but has fixed volume. Liquids take the shape of the container in which it is kept and also occupies space. The liquids have low inter-molecular force in between the molecules as compared to solids but higher than that of gases. The inter-molecular space between the molecules of liquid allows them to flow.

Liquids can expand more comparative to solid under the influence of thermal expansion. They are slightly more compressible. Under suitable conditions and temperature, the state of the solid can be changed into a liquid. Whereas, liquid can also be converted into solid.

Some of the examples of liquids are alcohol, water, oil, milk, etc.

Properties of Liquids

• Liquids have comparatively low inter-molecular force than solid.
• Liquids do not have fixed shape hence, takes the shape of the container in which it is kept.
• Liquids have fixed volume.
• Liquid as like solid cannot be compressed much.
• They have moderately high density. But not as much as solids.
• As the molecules are not tightly packed with each other they can flow.

### What are Gases?

Gas is a state of matter that does not have a fixed shape or volume. The shape and volume of gases depend on the container in which it is stored. The intermolecular force between the molecules of gases is negligible as the distance between the molecules is large. The inter-molecular distance between the molecules ranges from about 10-17  to 10-5.

The gases expand under the influence of thermal expansion as well as their volume can also be decreased as they are highly compressible. The molecules of gases show different forms of motion like rotatory, translatory, and vibratory.

Some of the examples of gases are air, oxygen, nitrogen, vapor, hydrogen, etc.

Properties of Gases

• Gases have a very low inter-molecular force acting between the molecules.
• They do not have a fixed shape or volume. The shape and volume change according to the container used to store it.
• Gases can be highly compressed. And, also can be changed into a liquid state.
• They have low density. Hence, they are very light in nature.
• As the molecules are loosely placed they can flow easily.

As now we have discussed the different states of matter and their properties let’s look into the question,

### Why do Solids, Liquids, and Gases have different properties?

As we know, all three states of matter differ in their properties. And there are some physical properties that decide the state of the substance whether it will exist as solid, liquid, or gas.

Kinetic Energy of particles of the substance:

Different states of matter show different types of movements or motions as per their rigidity. The motion in solids is the lowest in solid due to tightly packed molecules, comparatively more in liquid, and highest in gases as it has loosely placed molecules and provides space for motion.

The inter-molecular force between molecules:

The inter-molecular force depends on how closely the molecules are situated in a substance. The inter-molecular force is maximum in solids, comparatively less in liquid than solid, and minimum or nearly negligible in gases.

The distance between the molecules

The space between the particles determines their inter-molecular force and rigidity. The space between the particles of solid is negligible they are tightly packed to each other, distance is a little observable in liquid whereas, it is very high in gases.

### Sample Questions

Question 1: Mention some of the physical characteristics of matter.

• The matter is made up of tiny particles or molecules.
• The particles present in a matter show various types of motion.
• The particles constantly try to attract each other due to inter-molecular force.
• The inter-molecular distance decides their state.
• Each matter can be converted from one form to another under suitable conditions.

Question 2: Why do substances change their state matter?

When a substance gains energy its the motion of molecules present in the substance fastens and more kinetic energy is produced by them and pushes the particles apart from one another due to which their state gets changed.

Question 3: Which state of matter has the maximum amount of kinetic energy?

The gas particles have the maximum amount of kinetic energy relative to solid and liquid because the particles are set apart from each other which allows them free motion.

Question 4: What state of matter particles have the least energy?

Solid particles have the least amount of relative energy as the particles of solid are tightly packed to each other which does not allow different motions of the particle.

Question 5: What makes each state of matter different from the other?

The composition of particles makes each state of matter different. As the solid consists of tightly packed molecules, molecules in the liquid are fairly separated from each other, while molecules in a gas are loosely fitted apart from each other.

Question 6: Why do gases completely fill the vessel they are kept in?