Which of the following substances are elements?

Water, Salt, Mercury, Iron, Marble, Diamond, Wood, Nitrogen, Air, Graphite, Hydrogen, Oxygen, Sugar, Chlorine

Which of the following are ‘pure substance’?

Ice, Milk, Iron, Hydrochloric acid, Calcium oxide, Mercury, Brick, Wood, Air

What is the other name for impure substances? Give two examples of impure substances.

State three reasons why you think air is a mixture and water is a compound.

Name two solid, two liquids and two gaseous elements at the room temperature.