Elements, compounds and mixtures - (CCEA) The 3 states of matter: solids, liquids and gases
Most elements are rarely found in their pure form. They are found chemically combined with other elements in compounds. Compounds are often found mixed with other compounds. Mixtures may be separated and analysed.
Substances can also be classified as solids, liquids or gases.
The particles in a solid, liquid and gas are arranged differently:
Changes of state can happen if a substance is heated or cooled.
Some substances can change directly from solid to gas without becoming a liquid in between. This is called sublimationWhen a solid turns straight into a gas on heating, without becoming a liquid first - or when a gas turns straight into a solid, without becoming a liquid.. Under normal conditions, solid carbon dioxide ('dry ice') can sublimeAble to change from a solid to a gas, or from a gas to a solid, without becoming a liquid..