Purity and formulations

• What is a pure substance?

  A single element or compound that isn’t mixed with another substance
• How can the purity of a substance be tested?

  By comparing its melting or boiling point to the melting or boiling point of the pure substance

  • A purer substance has specific melting and boiling points
  • The purer the substance, the closer it’s melting and boiling points will be to the melting and boiling points of the pure substance
• What is a formulation?

  A mixture of substances in carefully measured quantities that has been designed to be a useful product
• What are some examples of formulations?

  Fuels, paints, medicines, alloys, cleaning products, fertilisers and foods
• What can happen to a formulation if the quantities of its components are changed?

  The properties of a formulation can be changed

  • e.g The properties of a fertiliser can be changed by changing the quantities of nitrogen, phosphorus and potassium in its formulation