PARTICULATE MODEL OF MATTER

What is matter made up of?

Matter is made of elements An element is made of tiny

particles All elements is made up of tiny

particles Particles in matter posses kinetic

energy and are constantly moving in a random manner.

Example of matter

Calcium Gold Nickel Sulfur Nickel Calcium

Sulfur

Gold

Evidence for moving particles

Diffusion is the process by which particles of matter fill a space because of random motion.

Movement of particles is always from a region of higher concentration to one of lower concentration.

Diffusion in gases

If a bottle of perfume is opened in one corner of a room, it spreads in the whole room by diffusion.

Diffusion in liquid If a bottle of perfume is opened in one

corner of a room, it spreads in the whole room by diffusion. If you drop a little ink in a breaker of water it will spread by itself and the colour spread uniformly.

Diffusion in solid When a lead plate and a gold plate are placed one over

the other if they are kept under pressure for a period of one or two years. It will be observed that the lead particles have diffused into gold and particles have diffused into lead plate. It is believed that fossils of animals like reptiles and leaves lie in contact with stones and rocks for number of years, which leaves an impression on the stones or rocks. This is because of the diffusion of the particles of the organic matter into the stones, which are in contact.

Solid

Regular arrangement Closely packed Strong forces of attraction Vibrate about fixed positions

Liquid

Random arrangement Further apart Move freely in all directions Moderate forces of attraction

between particles

Gas

Random arrangement Very far apart Move freely at great speeds in all

directions Very weak forces of attraction

between particles

Melting It is the process of changing a solid into its liquid

state. The temperature at which a solid changes to the liquid state is known as melting point. When a solid is heated, the molecules gain more kinetic energy and start vibrating with a greater velocity and greater amplitude. At a particular temperature, the molecules gain kinetic energy sufficient to overcome the force of inter-molecular attraction. They then start to slip and slide against each other. This process is called melting.

Evaporation All the molecules of a liquid are in a state of constant

and random motion. They have different velocities. During the motion, molecules collide against each other and some of the molecules gain more kinetic energy than others. The energy rich molecules break through the surface of the liquid. Thus the average kinetic energy of the remaining molecules decreases and this lowers the temperature of the liquid. Thus evaporation results in cooling.

Boiling

When a liquid is heated, the molecules gain more kinetic energy and the temperature starts rising. After it has reached a specific point though heat is being supplied, the temperature becomes steady. At this temperature the energy supplied gets utilized in breaking the inter-molecular force of attraction. Now the molecules start leaving the liquid and escape as vapor. This process is called boiling and the temperature is called boiling point.

Freezing

When a liquid is cooled(heat is removed), the particles lose energy and they move about more slowly.

Condensation

When a gas is cooled(heat is removed), the particles lose energy and they move about less vigorously and at lower speeds.

Property Solids Liquids Gases

Shape .Have fixed shapes

.Have no fixed shape.Take the shape of their containers

.Have no fixed shape.Take the shape of their containers

Volume .Have fixed volumes

.Have fixed volumes

.Have no fixed volume.Fill up the shape of their containers

 

Compressibility .Cannot be compressed

.Cannot be compressed

.Can be compressed

 

Credits

Natalie Woo Gurpreet Kaur Anjar Saridiyah Bte Kasman