IGCSE Chemistry- Atoms

States of Matter

Solids: 

• In a solid particles are close and touching
• They are arranged in a regular, repeating pattern
• The particle vibrate about in their fixed positions but DO NOT move apart
• There are strong forces between particles

Liquids:

• Partices in liquids are close together and touching one another
• The are arranged in an irregular pattern 
• The particles move around and slide past each other
• There are forces between particles, but not as strong as solids

Gases:

• Particles in gases are far apart
• The are arranged in a irregular patter
• The particles move freely and constantly collide with each other
• There are no forces between particles

Substances can change from one state to another

Movement of Particles

DIFFUSION= the gradual movement of particles from an area where there are lots of them to places where there are fewer of them

Showing diffusion

1. You can use Potassium Manganate (VII) and water

Take a beaker of water and add potassium manganate into it, Potassium Manganate is purple, this purple will slowly spread out and fill the beaker. 

The particles of potassium manganate are diffusing out among the particles of water. 

If you add more water, the solution becomes more dilute

2. You can use Ammonia and Hydrogen Chloride

Agueous ammonia (NH3) gives off ammonia gas.

Hydrochloric acid (HCL) gives off Hydrogen chloride

If you set up an experiment like this; 

You will get a white ring of ammonium chloride forming in the glass tube. 

The NH3…