Chapter 3: Matter and States of Matter

Matter

  • Definition of Matter:

    • Matter is any substance that has mass and occupies volume.

  • Physical States of Matter:

    • Matter exists in three physical states:
    • Solid
    • Liquid
    • Gas

Solid State

  • Properties of Solids:
    • Particles are tightly packed together.
    • Have a definite, fixed shape.
    • Cannot be compressed and have a definite volume.
    • Possess the least energy among the three states.

Liquid State

  • Properties of Liquids:
    • Particles are loosely packed and can move past one another.
    • Have an indefinite shape and take the shape of their container.
    • Cannot be compressed and possess a definite volume.
    • Have more energy than solids but less than gases.

Gaseous State

  • Properties of Gases:
    • Particles are far apart and uniformly distributed throughout the container.
    • Have an indefinite shape and volume, taking the shape of their container.
    • Can be compressed and possess the most energy of the three states.

Changes in Physical States

  • Physical State Changes:
    • Most substances can exist as solid, liquid, or gas depending on temperature.
    • Example for Water:
    • Solid below 0 °C
    • Liquid between 0 °C and 100 °C
    • Gas above 100 °C
Phase Changes Overview

  • Solid ↔ Liquid:

    • Melting: Solid to liquid as temperature increases.
    • Freezing: Liquid to solid as temperature decreases.

  • Liquid ↔ Gas:

    • Vaporizing: Liquid to gas as temperature increases.
    • Condensing: Gas to liquid as temperature decreases.

  • Solid ↔ Gas:

    • Sublimation: Solid to gas as temperature increases.
    • Deposition: Gas to solid as temperature decreases.

Classifications of Matter

  • Two Classes:
    • Mixtures: Can be physically separated; composed of more than one substance.
    • Pure Substances: Cannot be physically separated; composed of only one substance.
Mixture Types
  • Heterogeneous Mixtures: Non-uniform properties (e.g., sand and water).
  • Homogeneous Mixtures: Uniform properties (e.g., salt water).
Pure Substance Types
  • Compounds: Can be chemically separated into individual elements (e.g., water).
  • Elements: Cannot be broken down further by chemical reactions.

Element Names and Classifications

  • Unique names derived from various origins (e.g., Hydrogen from Greek).
  • Types of Elements:
    • Metals: Usually solid, high melting points, good conductors.
    • Nonmetals: Usually low melting points, poor conductors.
    • Semimetals (Metalloids): Midway properties.

Periodic Table of Elements

  • Description:
    • Each element assigned an atomic number, ordered by this number (e.g., Hydrogen = 1, Helium = 2).

Properties of Metals and Nonmetals

  • Metals:
    • Physically solid, malleable, ductile, good conductors of heat and electricity.
  • Nonmetals:
    • Low melting points, brittleness, poor conductors, dull appearance.

Chemical Formulas and Properties

  • Molecules: Composed of two or more nonmetal atoms.
  • Chemical Formula: Represents the number of atoms in a molecule (e.g., (H<em>2SO</em>4)(H<em>2SO</em>4) for sulfuric acid).

Changes in Matter

  • Physical Change: Composition does not change (e.g., melting, freezing).
  • Chemical Change: Composition changes; evidence includes gas release or color change.

Laws of Conservation

  • Conservation of Mass: Mass of reactants equals mass of products in chemical reactions.
  • Energy Conservation: Energy cannot be created or destroyed; can change forms.
    • Relation: (E=mc2)(E = mc^2).

Forms of Energy

  • Types of Energy: Heat, light, chemical, electrical, mechanical, nuclear.
  • Temperature affects kinetic energy which influences the physical state of matter (solids < liquids < gases).

Critical Thinking Example: Gasoline Purchase

  • Fill gas tank in cooler temperatures to obtain a greater mass of gasoline due to less expansion at lower temperatures.
  • Difference in mass between temperatures is minimal (approx. 1%).