5.1 Matter in Nature
Matter is defined as anything that has mass and occupies space (has volume). All living things (e.g., humans, animals, plants) and non-living things (e.g., air, water, soil) are made of matter.
Physical and Chemical Properties of Matter
- Physical Properties: Characteristics that can be observed or measured without changing the chemical composition of the substance. Examples include boiling point, melting point, solubility, heat conductivity, and electrical conductivity.
- Chemical Properties: Characteristics that describe how a substance changes into a completely different substance through chemical reactions. Examples include flammability, rusting, reactivity, and acidity/alkalinity.
Classifying Materials by Specific Characteristics
- Melting Point: Temperature at which a solid turns into a liquid.
- Boiling Point: Temperature at which a liquid turns into a gas.
- Solubility: Maximum amount of solute that dissolves in a given amount of solvent at a specific temperature.
5.2 Three States of Matter
Matter exists in three primary states: Solid, Liquid, and Gas. These states differ based on kinetic theory—how their constituent particles are arranged and move.
Comparison Between States of Matter
- Solid:
- Particle Arrangement: Very closely packed in an orderly, fixed pattern.
- Particle Movement: Vibrate and rotate about their fixed positions only.
- Shape & Volume: Fixed shape and fixed volume. Incompressible.
- Liquid:
- Particle Arrangement: Closely packed but not in an orderly pattern.
- Particle Movement: Move randomly, slide, and collide over one another.
- Shape & Volume: Fixed volume, but takes the shape of its container. Slightly compressible.
- Gas:
- Particle Arrangement: Very far apart in random, dispersed positions.
- Particle Movement: Move rapidly and randomly in all directions.
- Shape & Volume: No fixed shape and no fixed volume. Easily compressed.
Diffusion in Matter
Diffusion is the movement of particles from a region of higher concentration to a region of lower concentration. Diffusion occurs fastest in gases and slowest in solids due to particle arrangement and kinetic energy differences.
Changes in States of Matter
Changes of state occur when heat energy is absorbed or released by matter:
- Melting: Solid $\rightarrow$ Liquid (Heat absorbed)
- Freezing: Liquid $\rightarrow$ Solid (Heat released)
- Boiling / Evaporation: Liquid $\rightarrow$ Gas (Heat absorbed)
- Condensation: Gas $\rightarrow$ Liquid (Heat released)
- Sublimation: Solid $\rightarrow$ Gas (Heat absorbed)
- Deposition: Gas $\rightarrow$ Solid (Heat released)
During a change of state (e.g., melting or boiling point), the temperature remains constant because the thermal energy absorbed or released is used to break or form inter-particle bonds rather than change kinetic energy.