IGCSE Chemistry Notes
IGCSE
Complete Chemistry Notes
Unit 1: States of matter
Everything is made of particles. Particles in solid are not free to move around. Liquids and gases can. As particles move they collide with each other and bounce off in all directions. This is called random motion.
In 2 substances, when mixed, particles bounce off in all directions when they collide. This mixing process is called diffusion. It’s also the movement of particles without a force.
The smallest particle that cannot be broken down by chemical means is called an atom.
·In some substances, particles are just single atoms. For example the gas argon, found in air, is made up of single argon atoms.
·In many substances, particles consist of 2 atoms joined together. These are called molecules.
·In other substances, particles consist of atoms or groups of atoms that carry a charge. These particles are called ions.
Solids liquids and gases
Solid Properties:
• Definite shape and volume
• Normally hard and rigid
• Large force required to change shape
• High Density
• Incompressible
Model:
• Closely packed
• Occupy minimum space
• Regular pattern
• Vibrate in fixed position
• Not free to move
Liquid Properties:
• Definite volume but no shape.
• High Density
• Not compressible
Model:
• Occur in clusters with molecules slightly furt
• Free to move about within a confined vessel
wwPDwF W.ateirmagrk cRemsover DEMaOt: Pu.rchuaseafrom www.PDFWatermarkRemover.com to remove the watermark
Gas Properties:
• No Fixed volume and no fixed shape
• Low density
• Compressible
Model:
• Very far apart
• Travel at high speed
• Independent and random motions
• Negligible forces of attraction between them
Diffusion in Gases
Gases diffuse in different rates. Those rates depend on their factors:
1. Mass of the particles
The lower the mass of its
Complete Chemistry Notes
Unit 1: States of matter
Everything is made of particles. Particles in solid are not free to move around. Liquids and gases can. As particles move they collide with each other and bounce off in all directions. This is called random motion.
In 2 substances, when mixed, particles bounce off in all directions when they collide. This mixing process is called diffusion. It’s also the movement of particles without a force.
The smallest particle that cannot be broken down by chemical means is called an atom.
·In some substances, particles are just single atoms. For example the gas argon, found in air, is made up of single argon atoms.
·In many substances, particles consist of 2 atoms joined together. These are called molecules.
·In other substances, particles consist of atoms or groups of atoms that carry a charge. These particles are called ions.
Solids liquids and gases
Solid Properties:
• Definite shape and volume
• Normally hard and rigid
• Large force required to change shape
• High Density
• Incompressible
Model:
• Closely packed
• Occupy minimum space
• Regular pattern
• Vibrate in fixed position
• Not free to move
Liquid Properties:
• Definite volume but no shape.
• High Density
• Not compressible
Model:
• Occur in clusters with molecules slightly furt
• Free to move about within a confined vessel
wwPDwF W.ateirmagrk cRemsover DEMaOt: Pu.rchuaseafrom www.PDFWatermarkRemover.com to remove the watermark
Gas Properties:
• No Fixed volume and no fixed shape
• Low density
• Compressible
Model:
• Very far apart
• Travel at high speed
• Independent and random motions
• Negligible forces of attraction between them
Diffusion in Gases
Gases diffuse in different rates. Those rates depend on their factors:
1. Mass of the particles
The lower the mass of its