How bonding and structure are related to the properties of substances

2.2.1  The three states of matter
Properties of Solids, Liquids and Gases
Solid Liquid Gas
  • Close together in regular pattern
  • Strong intermolecular force of attraction
  • Vibrate at fixed position
  • Fixed shape & volume
  • Close together in random pattern
  • Further apart than solid
  • Weaker intermolecular force of attraction
  • Slide past each other
  • Can’t be compressed coz large intermolecular forces when molecules moved closer
  • Far apart in random pattern
  • Weaker intermolecular force of attraction
  • Move quickly in all directions
  • Can flow or compress

State Changes

States of matter can be represented using a model called particle theory.

How are particles represented in this model? (1)

Small solid spheres

Explain the limitations of particle theory (2)

  • Doesn’t show forces between particles
  • Particles are not solid spheres
  • Particle theory can be used to explain changes of state.
  • Using particle theory, explain how a substance changes from a liquid to a gas when it is heated. (3)
  • When a liquid is heated, particles gain KE & move faster
  • Weakens bonds holding liquid tgt
  • At certain temp, particles have sufficient energy to break bonds
  • Liquid becomes gas
  • 2.2.2  State symbols
    Solid (s), Liquid (l), Gas (g), Aqueous solution (aq)
  • 2.2.3  Properties of ionic compounds

(See 2.1.2 Ionic bonding)

2.2.4  Properties of small molecules

(See 2.1.4  Covalent bonding)

2.2.5  Polymers

  • Long chain molecule made from joining many short molecules (monomers) together
  • Strong intermolecular force – hard to break – solid at room temp
  • Different polymers, different properties, different uses
  • Thermosoftening polymer Thermosetting polymer
    • Contain long polymer chains
    • Chains are not joined tgt (but are tangled up with each other)
    • Low melting point – soften and then melt when heated
    • Contain long polymer chains
    • Chains are joined by covalent bonds
    • High melting point – do not soften or melt when heated
  • 2.2.6  Giant covalent structures

    (See 2.1.4  Covalent bonding)

    2.2.7  Properties of metals and alloys

    (See 2.1.5  Metallic bonding)

    2.2.8  Metals as conductors

    (See 2.1.5  Metallic bonding)