PDF chapter test TRY NOW

1. Which of the following are pure substances?
Ice, Milk, Iron, Hydrochloric acid, Mercury, Brick and Water.
 
Pure substances are
 
Impure substances are
  
2. Oxygen is very essential for us to live. It forms 21% of air by volume. Is it an element or compound?
 
Oxygen is an , It contains the atoms of of the same kind.