TOPIC 1: STATES OF MATTER

States of matter definition

Solids, liquids and gases are different physical states based on particle arrangement and energy

Properties of solids

Particles closely packed in a regular arrangement, vibrate in fixed positions, strong forces of attraction, fixed shape and volume

Properties of liquids

Particles close together but irregular, can move past each other, weaker forces than solids, fixed volume but no fixed shape

Properties of gases

Particles far apart, move rapidly and randomly, negligible forces, no fixed shape or volume, easily compressed

Diffusion definition

Net movement of particles from a region of higher concentration to a region of lower concentration due to random motion

Diffusion in gases

Happens quickly due to high kinetic energy and large spaces between particles

Diffusion in liquids

Slower than gases due to closer particles and more collisions

Effect of temperature on diffusion

Higher temperature increases kinetic energy so diffusion rate increases

Brownian motion

Random movement of particles due to collisions with molecules in a fluid

Change of state

Melting, boiling, condensation and freezing caused by energy changes

Melting

Solid to liquid, particles gain energy and overcome some forces

Boiling

Liquid to gas, particles gain enough energy to overcome all forces

Condensation

Gas to liquid, particles lose energy and come closer together

Freezing

Liquid to solid, particles lose energy and form fixed structure

Sublimation

Solid changes directly to gas without becoming liquid

Evaporation

Surface particles escape from liquid at temperatures below boiling point

Factors affecting evaporation

Temperature, surface area, air movement