1. States of matter Flashcards
Solid
A fundamental state of matter. All the particles within solid substances are bound to each other and vibrate around a fixed position. Solids have a fixed shape and volume.
Liquid
A fundamental state of matter. Particles in a liquid are physically bound, but they are able to move past each other. Liquids have a fixed volume but not a fixed shape
Gas
A fundamental state of matter. Particles in a gas are not physically bound to other particles. They move quickly and randomly. Gases have neither a fixed volume nor shape and can be compressed.
Melting
The process by which particles in a solid change state to become a liquid.
Boiling (evaporation)
The change of state from a liquid to a gas.
Condensation
The process by which particles in a gas change state to become a liquid.
Freezing (solidifying)
The process by which particles in a liquid change state to become a solid.
Sublimation
The process whereby a solid changes state to become a gas.
Not required learning for IGCSE Chemistry.
Solid (particle arrangement)
- Regular arrangement
- Tightly packed (touching)
- Vibrate about their position
- Strong forces of attraction holding them in place.
Liquid (particle arrangement)
- No regular arrangement
- Tightly packed (touching)
- Move randomly at different speeds
- Don’t move far because they frequently collide with each other
- Weaker forces of attraction than solids.
Gas (particle arrangement)
- No regular arrangement
- Move randomly at different speeds but faster than liquids
- Very weak forces of attraction compared to solids.
Effects of temperature on the volume of a gas. + (Explained)
- As heat is increased particles move faster.
- Thus volume increases bc particles move further in random directions.
- When temperature decreases so does volume.
Explained
- As temperature of gas dereases the particles move more slowly + closer together.
- Thus volume decreases. + inverse when temperature increases.
- The volume of a gas increases with temperature (with constant pressure) Thus temperature is proportional to volume
Effects of pressure on the volume of a gas + (Explained)
- Pressure is the amount of force applied to the surface of an object over a particular unit area.
- In a gas, the particles exert pressure on the walls (or sides) of any container in which they are held. Gas particles collide with the walls creating pressure.
- When you increase pressure of a gas at a fixed temperature the volume decresases.
- The gas has the same number of particles but there is less volume. Thus the same number of particles will exert more collisions on the sides of the container causing pressure to increase.
- When you decrease pressure of a gas the volume of a gas increases.
Explained
- Pressure applied –> particles forced to move closer together. Overall kinetic energy doesn’t change.
- The number of particles within gas is constant.
- Thus as particles move closer together the volume decreases. Pressure increases due to more collisions. + Inverse is true with a decrease in pressure.
- Pressure in inversely proportional to volume (at a constant temperature)
Can be written as…
P ∝1/V
DIffusion
The movement of particles from an area of high concentration to an area of low concentration, until the concentrations are even throughout. Diffusion is a random process and affected by temperature, pressure and molecular mass.
Effect of relative molecular mass on the rate of diffusion of gases.
The smaller the molecular mass, the faster the rate of diffusion. (Larger molecules require more kinetic energy to move –> All substances have the same average kinetic energy at the same temperature. Those with more mass require more to move –> move slower.)
