physical and chemical changes

It is a process of depositing a layer of zinc on iron articles to prevent them from rusting.

The brownish deposit on an iron material which is left in the open for some time is called --.

Pure and bigger crystals can be obtained by the process of -

• Condensation

• Distillation

• Evaporation

• Crystallization

A -- change is generally irreversible.

When carbon dioxide is passed through limewater, it turns milky due to the formation of -

• Magnesium oxide

• Calcium carbonate

• Carbon dioxide

• Carbonic acid

When a firecracker bursts, it is a -

• Physical change

• Chemical change

Iron and rust are the same substance.

• True

• False

Iron pipes coated with zinc do not get rusted easily.

• True

• False

A change in which no new substance is formed.

What colour of flame is observed when magnesium burns ?

• Dazzling blue

• Dazzling white

• Dazzling green