Characteristics of Matter

Study Notes

Matter occupies space and has mass, made up of atoms, the smallest building blocks.
Molecules consist of two or more atoms bonded together.

According to Composition:
- Substances have a definite composition and distinct properties.
  - Elements: Unique types of atoms, cannot be decomposed further (e.g., Aluminum).
  - Compounds: Composed of two or more elements (e.g., Aluminum oxide).
Mixtures consist of two or more substances maintaining their chemical identities.
- Components are the individual substances in a mixture.
- Heterogeneous Mixtures: Vary in composition and appearance (e.g., salad).
- Homogeneous Mixtures: Uniform throughout (e.g., saltwater).
According to State:
- Gas: No fixed volume or shape.
- Liquid: Fixed volume, takes the shape of its container.
- Solid: Fixed shape and volume.

Physical properties are observed without altering the substance's identity.
- Intensive Properties: Do not depend on the amount of substance (e.g., density).
- Extensive Properties: Depend on the quantity of substance (e.g., mass, volume).

Chemical properties describe how a substance may transform into others.
- Heat of Combustion: Energy released during combustion.
- Chemical Stability: Reactivity of a compound with water or air.
- Flammability: The ability of a substance to burn when exposed to flame.

Chemical Changes: Transform a substance into a chemically different one.
Chemical Equations: Use symbols to depict reactants (starting materials) and products (substances formed).
- Reactants are written on the left; products on the right of the arrow (e.g., KBr(aq) + KNO3(aq) + AgNO3(aq) → AgBr(s)).
Physical states are indicated by:
- g: Gas
- l: Liquid
- s: Solid
- aq: Aqueous (dissolved in water).