The States of Matter Study Notes

The States of Matter

Definition of Matter

  • Matter: Anything that has mass and occupies space.
      - Made up of particles.
      - Can exist in three states:
        1. The solid state
        2. The liquid state
        3. The gaseous state

The Particulate Theory of Matter

  • The particulate theory of matter consists of four key ideas:
      - Composition of Particles: All matter is composed of particles.
      - Motion of Particles: Particles are in constant motion.
        - The speed of motion is dependent on temperature.
      - Spacing of Particles: There are empty spaces between the particles.
      - Forces of Attraction: There are forces of attraction between the particles.

Evidence Supporting the Particulate Theory

  • Processes Demonstrating Particle Behavior:
      - Diffusion:
        - Definition: The net movement of particles from a region of high concentration to a region of low concentration until evenly distributed.
      - Osmosis:
        - Definition: The net movement of water molecules from a place of high concentration to a place of low concentration over a differentially permeable membrane until evenly distributed.

Examples of Diffusion

  • Example 1: Reaction of Ammonia and Hydrogen Chloride Gas
      - Description: The particles of each gas diffuse along the tube and collide to form ammonium chloride.
  • Example 2: Placing Potassium Manganate Crystals in Water
      - Description: The crystal particles diffuse throughout the water until evenly distributed.

Examples of Osmosis

  • Example 1: Concentrated and Dilute Sucrose Solution
      - Description: Water molecules move from the dilute solution through the membrane to the concentrated solution, increasing the volume of the solution inside the glass tube.
  • Example 2: Placing Potato Pieces in Different Concentration Salt Solutions
      - Description: In solutions of similar concentration, water movement is equal. Water moves out of the potato pieces in a concentrated solution causing them to shrink. Water moves into the potato pieces in a dilute solution causing them to swell.

Uses of Osmosis

  • Applications of Osmosis include:
      - Controlling garden pests like snails and slugs.
      - Preserving food.
      - Water purification.

Types of Particles

  1. Atoms: The smallest units of a chemical element.
       - Example: Iron is made up of iron atoms.
  2. Molecules: Groups containing two or more atoms bonded together.
       - Example: Water (H₂O) consists of 2 hydrogen atoms and 1 oxygen atom.
  3. Ions: Electrically charged particles formed from single atoms.
       - Example: The potassium ion (K⁺) carries a positive charge.

The Three States of Matter


  • Comparison of Properties among Solid, Liquid, and Gas:

PropertySolidLiquidGas
ShapeFixedTakes the shape of the part of the container it is in.
VolumeFixedFixedVariable; expands to fill the entire container.
DensityUsually highUsually lower than solids.Low.
CompressibilityDifficult to compressCan be compressed very slightly by applying pressure.Very easy to compress.
Arrangement of ParticlesPacked closely together, usually in a regular way.Small spaces between and randomly arranged.Large spaces between and randomly arranged.
Forces of AttractionStrongWeaker than solids’ forces of attraction.Very weak.
Energy Possessed by ParticlesPossess very small amounts of kinetic energy.Possess more kinetic energy than particles in a solid.Possess large amounts of kinetic energy.
Movement of ParticlesVibrate in fixed positions.Move slowly past each other.Move around freely and rapidly.

Changing States of Matter

  • General Principle: Matter exists in different states depending on its temperature.
  • Heat Up (Heating): When heat is added, particles gain kinetic energy…
      - Particles move more quickly and further apart; forces of attraction weaken.
      - Change of state occurs from solid to liquid to gas.
  • Cool Down (Cooling): When heat is removed, particles lose kinetic energy…
      - Particles decrease speed and come closer together; forces of attraction strengthen.
      - Change of state occurs from gas to liquid to solid.

Evaporation and Boiling

  • Boiling:
      - Process where a substance changes state from liquid to gas.
      - Characteristics:
        - Fast.
        - Bubbles are formed.
        - Occurs throughout the liquid.
        - Occurs at a definite temperature (boiling point).
        - Requires energy source.
  • Evaporation:
      - Process where a substance changes state from liquid to gas without boiling.
      - Characteristics:
        - Slow.
        - No bubbles formed.
        - Occurs only from the exposed surface of the liquid.
        - Occurs at all temperatures.
        - Energy is supplied by surroundings.

Sublimation and Deposition

  • Sublimation:
      - Definition: Change directly from solid to gas.
      - Example: Solid carbon dioxide (dry ice).
  • Deposition:
      - Definition: Change directly from gas to solid.
      - Example: Iodine gas changing to solid crystals on contact.

Heating and Cooling Curve

  • Heating and Cooling Curve Description:
      - Temperature is measured at intervals as a substance is heated or cooled, and temperature is plotted against time.
  • Key Points:
      - Melting Point: The temperature where a solid changes into a liquid.
      - Boiling Point: The temperature where a liquid changes into a gas.
      - Freezing Point: The temperature where a liquid changes into a solid.

Temperature Behavior on Heating and Cooling Curve:

  • Graphical Representation:
      - Solid: Temperature increases as time progresses.
      - Liquid: Temperature remains constant at melting/freezing or boiling/condensation points until transitions are complete.
      - Gas: Temperature increases after all liquid has boiled.

References:

  • Tindale, A. (2016) CONCISE REVISION COURSE ® •CSEC CHEMISTRY. London: Collins HarperCollins Publishers Ltd