1.1. Matter. States of Matter


Matter. States of matter.


Chemistry: The study of matter and how it changes

What is matter?

  • Anything that has a mass.
  • [Anything you can touch, see or see in an instrument (e.g. a telescope or a microscope).]


  • Iron
  • Wood
  • Air
  • Water
  • Plastic

How does matter change? Examples:

  • Ice melts
  • Iron corrodes
  • Children grow
  • Plants grow
  • Petrol burns
  • … and much, much more

Phase transitions

Melting & solidification (freezing)

Phase transitions.Phase transitions.Ice melts:

  • Solid water, H2O(s), with energy added gives liquid water, H2O(l).
  • H2O(s) + energy → H2O(l)

Water freezes:

  • Liquid water, H2O(l) freezes and forms solid water (ice), H2O(s). At the same time, energy is released.
  • H2O(l) → H2O(s) + energy

Evaporation & condensation

Liquid water evaporates:

  • Liquid water, H2O(l), with energy added gives water vapor, H2O(g)
  • H2O(l) + energy → H2O(g)

Water vapor condenses:

  • Water vaper condenses into liquid water. At the same time, energy is released.
  • H2O(g) → H2O(l) + energy

Sublimation & deposition

Matter passes from solid to gas without passing liquid state.

Example: Solid iodine, I2(s), sublimates with added energy forms iodine vapor.

  • I2(s) + energy → I2(g)
Iodine sublimes.Iodine sublimes. Iodine deposits.Iodine deposits.

Ionization & deionization

Our sun and most stars are made of plasma.Our sun and most stars are made of plasma.If enough energy is added, one or more electrons are removed from the atom. This creates positively charged ions.

Most abundant state of matter in the universe: The sun and all the stars are made of plasma.