Unit 2.1 Matter - Chem

Unit 2 Overview

  • Focus on: Matter, Phase Change, and Chemical vs Physical Change

Matter

  • Defined as anything that has mass and occupies space (volume).

Phase Change

  • Involves transitions between solid, liquid, gas, and plasma states.

  • Related to heat transfer and particle motion.

Chemical vs Physical Change

  • Chemical Change: Involves a change in the chemical identity of a substance.

  • Physical Change: Alters the form, not the composition, e.g., melting, boiling.

NC Standards Classifications

  • PSc.2.1.1 Classifications:

    • Homogeneous vs Heterogeneous:

      • Uniformity of Material.

    • Pure Substances vs Mixtures:

      • Number of Elements or Compounds.

    • Elements as Metals, Nonmetals, or Metalloids:

      • Based on Periodic Table Position.

    • Chemical Formula Classification:

      • Elements vs Compounds.

    • Solutions, Colloids, Suspensions:

      • Based on Particle Size, Settling Properties, Light Interaction (Tyndall Effect).

NC Standards on Phase Changes

  • PSc.2.1.2 Models of Phase Change:

    • Relationship among:

      • Particle Attraction

      • Particle Motion

      • Heat Gain/Loss

    • Key Phase Changes:

      • Solid to Liquid: Melting

      • Liquid to Gas: Vaporization

      • Gas to Liquid: Condensation

      • Liquid to Solid: Freezing

Classification of Matter

  • Pure Substances: Uniform composition, cannot be decomposed.

  • Mixtures: Combinations of pure substances, can be separated:

    • Homogeneous Mixtures (solutions): Uniform (e.g., air, sugar in water).

    • Heterogeneous Mixtures: Non-uniform (e.g., granite, wood).

  • Elements: Simplest form (e.g., gold, oxygen).

  • Compounds: Combination of elements (e.g., water, NaCl).

Phases of Matter

  • Solid:

    • Definite Volume & Shape.

    • Examples: Salt, Ice.

  • Liquid:

    • Definite Volume, No Definite Shape.

    • Examples: Water, Mercury.

  • Gas:

    • No Definite Volume or Shape.

    • Examples: Air, Helium.

  • Plasma:

    • No Definite Volume or Shape.

    • Examples: Lightning, Sun.

Phase Change and Energy

  • Ionization: Gas turns into plasma through heat energy, causing electron loss.

Properties of Matter

  • Physical Properties: Can be observed without changing chemical identity (color, length, volume).

  • Chemical Properties: Observed during a chemical change (acidity, reactivity, flammability).

Comparing Changes

  • Chemical Change Examples:

    • Combustion, Rusting, Digestion.

  • Physical Change Examples:

    • Boiling, Melting, Shredding.

Solutions, Suspensions, Colloids

  • Solution: Transparent, homogeneous, cannot settle or be filtered.

  • Suspension: Cloudy, heterogeneous, separates when left to stand and can be filtered.

  • Colloid: Intermediate, does not separate but can scatter light (Tyndall effect).

Separation Techniques

  1. Filtration: Separates solid from liquid using filter paper.

  2. Distillation: Separates liquids based on boiling points.

  3. Chromatography: Separates components in a mixture based on their movement through a medium.