Purity and formulations

• What can a pure substance be in chemistry?

  Single element or single compound.
• What is a pure substance?

  When a substance is not mixed with any other substances.
• When does a pure substance melt?

  At a specific fixed temperature. It also has a specific fixed boiling point.
• When do impure substances melt and boil?

  They melt and boil at a range of temperatures.
• What happens the temperature stops rising first at a certain point?

  Its the substances melting point.
• What happens when the temperature of a substances stops for a second time at a certain fixed point.

  Its the substances boiling point.
• How do we know if a substance is pure?

  If there melting and boiling points are at specific fixed temperatures.
• What is a formulation?

  A complex mixture that has been designed as a useful product. In a formulation, the quantity of each component is carefully measured so that the product has the properties we need.
• What are some examples of formulations?

  Fuels, paints, medicines and fertilisers.