Chemistry – year 8
Let’s explore the Particle Model of Matter, Changes of State, and Gas Pressure and
Particle Collisions in more detail:
1. Particle Model of Matter:
• All matter is composed of tiny particles (atoms or molecules).
• These particles are in constant motion, vibrating or moving freely.
• There are spaces between particles, even in solids.
• Attractive forces (intermolecular forces) exist between particles.
• The particle model helps explain properties like density, diffusion, and
thermal expansion.
2. Changes of State:
• Melting: Solid to liquid transition. Heat energy breaks intermolecular
bonds.
• Boiling/Evaporating: Liquid to gas transition. Heat energy overcomes
intermolecular forces.
• Freezing/Condensing: Gas or liquid to solid transition. Heat energy is
removed.
3. Gas Pressure and Particle Collisions:
• Gas particles move randomly and collide with each other and container
walls.
• These collisions create pressure.
• Increasing temperature or particle speed increases pressure.
Let’s explore the Particle Model of Matter, Changes of State, and Gas Pressure and
Particle Collisions in more detail:
1. Particle Model of Matter:
• All matter is composed of tiny particles (atoms or molecules).
• These particles are in constant motion, vibrating or moving freely.
• There are spaces between particles, even in solids.
• Attractive forces (intermolecular forces) exist between particles.
• The particle model helps explain properties like density, diffusion, and
thermal expansion.
2. Changes of State:
• Melting: Solid to liquid transition. Heat energy breaks intermolecular
bonds.
• Boiling/Evaporating: Liquid to gas transition. Heat energy overcomes
intermolecular forces.
• Freezing/Condensing: Gas or liquid to solid transition. Heat energy is
removed.
3. Gas Pressure and Particle Collisions:
• Gas particles move randomly and collide with each other and container
walls.
• These collisions create pressure.
• Increasing temperature or particle speed increases pressure.
