The Particulate Nature of Matter
The Particulate Nature of Matter
Basic Principles
- All substances are made of particles.
- These particles could be atoms, molecules, or ions.
- These particles are in constant motion; higher the temperature, quicker the movement.
- There are spaces between particles.
States of Matter
- Matter exists in three states: Solid, Liquid, and Gas.
- In solids, particles are packed closely in a fixed pattern. They can only vibrate around a fixed point.
- In liquids, particles are close but can move around each other. This means liquids can flow and take shape of their containers.
- In gases, particles are well separated and move quickly in all directions. Gases fill their containers completely.
Changes of States
- Melting and Freezing: The change from solid to liquid is called melting, whereas the change from liquid to solid is freezing.
- Boiling and Condensing: Liquid turning into gas is boiling or evaporation, while gas changing to liquid is called condensing.
- Sublimation: Certain substances can change from solid directly to gas, bypassing the liquid state. This process is called sublimation.
Kinetic Particle Theory
- The Kinetic Particle Theory explains the properties of different states of matter.
- This theory considers both the movement of particles (kinetic energy) and the attraction between them.
- In solids, the attractive forces are strong, keeping particles in fixed positions, so solids keep their shape.
- In liquids, the attractive forces are weaker, allowing particles to move and slide past each other.
- In gases, the attractive forces are very weak, letting particles move rapidly in all directions.
Diffusion
- Diffusion is the spreading of particles from an area of high concentration to one of low concentration.
- Diffusion occurs most quickly in gases, slower in liquids, and slowest in solids.
- Increased temperature boosts the speed of diffusion by increasing particle motion.
Brownian Motion
- Brownian Motion is the random, unpredictable movement of particles in a fluid, as observed under a microscope.
- This motion is caused by the collisions of the particles with each other.
- Brownian Motion is additional evidence of the particle nature of matter.