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

What are the two types of pure substance? Give one example of each type.

Which of the following are ‘pure substance’?

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

Which of the following substances are elements?

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

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