Understanding Matter: Properties and Classification

• Matter is anything that occupies space and has mass.
• Examples of matter: air, water, hydrogen, oxygen, sugar, sand, silver, steel, copper, coal, iron, wood, ice, alcohol, milk, oil, kerosene, petrol.
• For something to be considered matter, it must occupy space and have mass.
• Things like friendship, love, affection, hatred, good manners, thoughts, ideas, taste, and smell are not matter, as they do not occupy space or have mass.
• Ancient Indian philosophers believed that all matter (padarth) consists of five basic elements (panch tatva): air (vayu), earth (prithvi), fire (agni), sky (akash), and water (jal).
• Matter is classified based on physical properties as solids, liquids, and gases.
• Matter is classified based on chemical properties as elements, compounds, and mixtures.

Characteristics of Particles of Matter

• The particles of matter are very small.
• The particles of matter have spaces between them.
• The particles of matter are constantly moving.
• The particles of matter attract each other.

Dissolving Sugar in Water

• When sugar dissolves in water, its tiny particles break off from the solid sugar crystals.
• The sugar particles go into the spaces between the water particles and mix, forming a sugar solution.
• Dissolution of sugar in water shows that matter is made of small particles and that there are spaces between the particles.

Rigid vs. Fluid

• Rigid means unbending or inflexible (ex. stone).
• Fluid means a material that can flow easily and requires a container (ex. water).

Classification of Matter

• Matter is classified into three physical states: solids, liquids, and gases.

Properties of Solids

• Examples of solids: ice, wood, coal, stone, iron, brick.
• Solids have a fixed shape and a fixed volume.
• Solids cannot be compressed much.
• Solids have high densities and are heavy.
• Solids do not fill their container completely.
• Solids do not flow.

Properties of Liquids

• Liquids have a fixed volume but no fixed shape, taking the shape of their container.
• Liquids cannot be compressed much.
• Liquids have moderate to high densities, usually less dense than solids.
• Liquids do not fill their container completely.
• Liquids flow easily.

Properties of Gases

• Gases have neither a fixed shape nor a fixed volume, taking the shape and volume of their container.
• Gases can be compressed easily.
• Gases have very low densities and are very light.
• Gases fill their container completely.
• Gases flow easily.

Kinetic Theory of Matter

• According to the kinetic theory, particles of matter are in continuous motion and possess kinetic energy.
• Spaces between particles: minimum in solids, more in liquids, maximum in gases.
• Force of attraction between particles: strongest in solids, less strong in liquids, negligible in gases.
• Movement of particles (kinetic energy): minimum in solids, more in liquids, maximum in gases.

Solids (properties based on Kinetic Theory)

• Solids have a fixed shape because particles are closely packed and their positions are fixed due to strong attractive forces.
• Solids have a fixed volume because the spaces between particles are fixed.

Liquids (properties based on Kinetic Theory)

• Liquids do not have a fixed shape because the positions of particles are not fixed due to weaker attractive forces.
• Liquids have a fixed volume because, at a given temperature, spaces between particles are fixed.

Gases (properties based on Kinetic Theory)

• Gases do not have a fixed shape because the positions of particles are not fixed.
• Gases do not have a fixed volume because the spaces between particles are not fixed.

Matter Q&A

• Matter examples: chair, air, almonds, cold-drink.
• Non-matter examples: love, smell, hate, thought, cold, smell of perfume.
• A diver cutting through water demonstrates that matter is made of particles with space between them.

Differences in States of Matter

State of Aggregation:

• Solid: Particles are most closely packed.
• Liquid: Particles are less closely packed than solids.
• Gas: Particles are at sufficient distances from each other.

Shape:

• Solid: Definite shape.
• Liquid: No definite shape; takes the shape of the container.
• Gas: No definite shape.

Volume:

• Solid: Definite volume.
• Liquid: Definite volume.
• Gas: No definite volume.

Density:

• Solid: High density.
• Liquid: Less density than solids but more than gases.
• Gas: Least density.

Diffusion:

• Solid: No tendency to diffuse.
• Liquid: Tendency to diffuse slowly.
• Gas: Diffuses rapidly.

Rigidity:

• Solid: Rigid.
• Liquid: Fluid.
• Gas: Fluid.

Compressibility:

• Solid: Negligible.
• Liquid: Very low.
• Gas: High.

Intermolecular Forces of Attraction:

• Solid: Maximum.
• Liquid: Less than solids.
• Gas: Negligible.

Kinetic Energy of Molecules:

• Solid: Least.
• Liquid: More than solids.
• Gas: Very high.

Properties Defined

• Rigidity: Resistance to bending; solids are rigid as they resist shape change with external force.
• Compressibility: Solids have little; liquids are nearly incompressible; gases are easily compressed.
• Fluidity: Tendency to flow; requires a vessel or container; liquids and gases are fluids.
• Filling a Gas Container: Gases fill the container completely.
• Shape: Solids have a fixed shape; liquids and gases do not.
• Kinetic Energy: Molecules in solids possess the least kinetic energy; gases have very high kinetic energy.
• Density: Solids have high density; gases have the least density.

Additional Q&A

• Gases fill their container completely due to a lack of fixed shape or volume, allowing particles to move freely.
• Gases exert pressure by colliding with each other and the container walls in a random manner.
• Wooden tables are solids due to their definite shape, volume, and distinct boundaries.
• Hand movement in air is easier than in wood because of the empty space between gas molecules, unlike the closely packed molecules in solids.

Forces of Attraction (increasing order)

• Oxygen (gas) < water (liquid) < sugar (solid).

Interparticle Spaces (correct order)

• Solid < liquid < gas.

Fluidity

• Gases and liquids are fluids.

Differences: Solids, Liquids, Gases

• Arrangement of Particles
• Attractive Forces
• Spacing

Gases in Cylinders

• Gases are highly compressible.

Notes

• Rubber band properties: A rubber band is considered a solid. It changes shape under force but returns to its original shape when the force is removed, unless stretched with a large force.
• Sponge properties: A sponge is considered a solid whose compressibility is due to the presence of minute air-filled pores.

Condensed Properties of Solids, Liquids and Gases

• Solids cannot be compressed
• Solids have a high density
• Solids do not fill their container completely
• Solids do not flow
• Liquids do not fill their container completely
• Liquids can flow easily
• Liquids cannot be compressed
• Liquids take the shape of their container
• Gases can be compressed easily
• Gases have a low density
• Gases fills its container completely
• Gases take the shape and volume of its container
• Gases flow easily