CHEM104 Lecture Chapter 1: Overview of Classification of Matter

Key Concepts

• Periodic Table: An essential tool in chemistry, listing all chemical elements that are the building blocks of the material world.
• Matter: Anything with mass and occupies space. Examples include elements, compounds, mixtures, stars, water, rocks, etc.

Classification of Matter

• Pure Substances: Fixed composition, can be described by a single chemical formula.

  • Examples: Water (H2O), Salt (NaCl)

• Mixtures: Varying composition, require more than one chemical formula.

  • Examples: Saltwater, Air

Types of Substances

1. Elements

   • Simplest chemical substances, found on the periodic table.
   • Composed of one kind of atom.
   • Examples: Copper (Cu), Oxygen (O2), Helium (He)

2. Compounds

   • Pure substances that contain more than one kind of atom.
   • Can be decomposed chemically into elements.
   • Examples: Water (H2O), Carbon Dioxide (CO2), Table Sugar (C12H22O11)

Mixtures

1. Homogeneous Mixtures (Solutions)

   • Evenly mixed, uniform composition throughout.
   • Examples: Air, Saltwater, Seltzer

2. Heterogeneous Mixtures

   • Uneven distribution, varying composition.
   • Examples: Living cells, Rocks, Sandwiches, Dirt

States of Matter

1. Solid

   • Definite shape and volume.
   • Atoms are closely packed, not free to flow.

2. Liquid

   • Definite volume, takes shape of its container.
   • Atoms are close but can flow past each other.

3. Gas

   • No definite shape or volume, fills container completely.
   • Atoms are far apart and free to move.

Concepts of Fluid and Condensed Phase

• Fluid: Anything that flows (liquid and gas).
• Condensed Phase: Closely packed atoms/molecules.
  • Solid: Condensed phase, not fluid.
  • Liquid: Condensed phase and fluid.
  • Gas: Fluid, not condensed phase.