# CHANGES IN STATES OF MATTER USING KINETIC THEORY

## Melting

When a solid is heated, the particles acquire more kinetic energy and vibrate more vigorously. Eventually, at a certain temperature called the melting point of the solid, the force of the vibrations overcome the binding forces and solid structure collapses. The particles are no longer in fixed positions, but free to move. At this point, the solid is said to have melted or liquified.

## Condensation and freezing

Condensation is a process whereby a vapour loses some of its kinetic energy when cooled and changes into liquid state. when   a liquid cool, it loses heat energy causing its temperature to drop. if cooling is allowed to continue, the temperature of the liquid keeps on dropping, until it reaches the freezing point of the liquid. The liquid changes into the solid state at this temperature. The freezing point of a substance is the same as its melting point.

## Diffusion

This is defined as the movement of solute particles through a medium, from a region of higher concentration to a region of lower concentration, that is, movement from a more crowded region to less crowded region. Once the solute particles become evenly distributed throughout the medium, there will be net diffusion in any particular direction. Diffusion is fastest in gases because gas particles have more kinetic energy than particles in liquids and solids.

## EVALUATION

1. When solids change into liquid at appropriate temperature, the process is called ———
2. Evaporation b. Melting c. Diffusion d. Boiling
3. The temperature at which liquid turn to solid is called ————- point.
4. Freezing point b. Cooling c. Boiling point d. Melting point
5. The process by which a gaseous matter comes back to a liquid matter is known as ———
6. Boiling b. Freezing c. Sublimation   d. Vaporization e. Condensation.
7. The direct conversion of solid matter to gas is called ——-

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MOLECULAR STRUCTURES USING KINETIC THEORY

KINETIC ENERGY

FAMILY LIFE EDUCATION

FAMILY LIFE EDUCATION

Energy Transfer (When work is done)