Particle Theory
Particle Theory
Basic Principles
- All matter is made up of tiny particles.
- Each type of material has a unique type of particle or mixture of particles.
- These particles are in constant, random motion.
- The higher the temperature, the faster they move.
Arrangement and Movement of Particles
- Particles of solids are arranged in fixed positions in a tight, regular pattern.
- They vibrate around a fixed point but do not change position.
- Liquid particles are not arranged as tightly as in solids, allowing them to slide over each other, explaining the fluid property.
- Gas particles have the most space and freedom and move all over the place in all directions.
Changes of State
- Adding or removing heat causes materials to change states.
- When a solid is heated, its particles vibrate more until they break free from their fixed positions and start sliding over each other. This is the process of melting.
- When a liquid is cooled, its particles begin to vibrate less and get closer together, forming a solid. This is the process of freezing.
- When a liquid is heated, its particles move faster and spread out to become a gas. This is the process of evaporation.
- When a gas is cooled, its particles slow down and come together to form a liquid. This is the process of condensation.
Density
- The density of an object is determined by the amount of particles in a given space.
- More densely packed particles result in a denser object.
- Density can be calculated using the formula: density = mass/volume.
Diminishing Particle Size and Surface Area
- The smaller the particles, the larger the exposed surface area.
- Larger surface area leads to faster rates of reaction because there are more opportunities for the substance to interact.
Diffusion
- Diffusion is a process where particles spread, mixing with each other without any external influence.
- Particles in a gas diffuse fastest due to the maximum space and freedom, followed by liquid and then solid.