Introduction to Matter and the Particle Theory

The Particle Theory of Matter

• Composition: All matter consists of particles.

• Identity: All particles within a single substance are identical.

• Motion: Particles are in constant motion.

• Temperature: Increased temperature increases the speed of particle motion.

• Attraction: Forces of attraction exist between particles.

• Gaps: There are spaces between particles.

Fundamental Properties of Matter

• Matter: Anything possessing both mass and volume.

• Mass: The quantity of matter (atoms) in a substance, measured in grams ($g$).

• Volume: The amount of space a substance occupies, measured in liters ($L$).

States of Matter and Their Physical Properties

• Solids: Possess a fixed shape and fixed volume; do not flow easily; not easily compressed.

• Liquids: Take the shape of their container but have a fixed volume; flow easily; not easily compressed.

• Gases: Take the shape and volume of their container; flow easily; easy to compress.

Phase Changes and Energy

• State Change Processes: Matter transitions between states via six processes: Melting, Freezing, Condensation, Evaporation, Sublimation, and Deposition.

• Causes: Changes are driven by the addition or removal of energy (heat).

• Critical Temperatures: Transitions occur at specific points, such as the Melting Point and Boiling Point, which vary by substance.

Classification of Matter

• Pure Substances: Consist of a single substance.

  • Elements: Made of only one type of atom (e.g., Hydrogen atoms); cannot be broken down physically or chemically.

  • Molecules: Two or more atoms chemically bonded (e.g., Ozone $O_{3}$). All compounds are molecules, but not all molecules are compounds.

  • Compounds: Two or more different elements in a fixed ratio (e.g., Salt $NaCl$); can be decomposed chemically.

• Mixtures: Combinations of different substances.

  • Homogeneous Mixtures (Solutions): Possess a uniform composition (e.g., alloys, salt water).

  • Heterogeneous Mixtures (Mechanical Mixtures): Possess a non-uniform composition (e.g., pizza, trail mix).

Matter Classification Flow

• Physical Separation: If matter can be physically separated, it is a Mixture; if not, it is a Pure Substance.

• Uniformity: A mixture with uniform composition is Homogeneous; otherwise, it is Heterogeneous.

• Chemical Decomposition: A pure substance that can be chemically decomposed is a Compound; if it cannot, it is an Element.