Matter in Our Surroundings - States of Matter

Matter is made up of tiny particles which have spaces between them, are continuously moving, and attract each other. The kinetic energy of particles increases with a rise in temperature ($T$).

Solid State: Characterized by definite shape, distinct boundaries, and fixed volumes. Particles have minimum space and maximum force of attraction. Solids are generally incompressible.

Liquid State: Particles have no fixed shape but a fixed volume. They take the shape of the container. The rate of diffusion of liquids is higher than solids because particles move freely.

Gaseous State: Particles have no fixed shape or volume. They have maximum kinetic energy and move randomly at high speeds. Gases are highly compressible, as seen in $LPG$ (Liquefied Petroleum Gas) and $CNG$ (Compressed Natural Gas).

Change of State: Temperature and pressure determine the state of a substance. Increasing temperature provides energy to overcome intermolecular forces (e.g., $Solid \xrightarrow{Fusion} Liquid \xrightarrow{Vaporisation} Gas$).

Latent Heat of Fusion: The amount of heat energy required to change $1\text{ kg}$ of a solid into liquid at atmospheric pressure at its melting point. For ice, this is approximately $3.34 \times 10^5\text{ J/kg}$.

Latent Heat of Vaporization: The heat energy required to change $1\text{ kg}$ of a liquid to gas at atmospheric pressure at its boiling point. Steam at $373\text{ K}$ has more energy than water at the same temperature due to this latent heat.

Sublimation and Deposition: Sublimation is the direct change from solid to gas without becoming liquid (e.g., Ammonium Chloride $NH_4Cl$, Solid $CO_2$). Deposition is the direct change from gas to solid.

Evaporation: A surface phenomenon where particles from the surface of a liquid gain enough energy to overcome forces of attraction and change into vapor. Factors affecting it include surface area, temperature, humidity, and wind speed.