Physical and chemical changes

It is not dangerous to look at burning magnesium for too long.

• True

• False

What is the other name for blue vitriol?

• Copper sulphate

• Magnesium hydroxide

• Sulphuric acid

What do carbon dioxide and lime water produce when they react with each other?

• CaCO3

• MgO

• CacO3

• CaCO3+water

Chemical name for magnesium hydroxide is :

(a)  

Choose the incorrect statement

• Ships suffer a lot of damage though they are painted

• Stretching of rubber band is a chemical change

• Formation of biogas is a chemical change

• Burning of candle is both physical and Chemical change

• Both b and d

Which of the following is not a physical property of a substance ?

• Shape

• Color

• Density

• Flammability

What is galvanisation?

• Painting with oil

• Process of depositing a layer of zinc on iron

• Process of depositing a layer of iron on zinc

Beating aluminium is what kind of change?

• Physical change

• Chemical change

Formula of rust is :

• Fe2o3

• Fe2o4

• Fe0

• Fe2o3.xH2O

Some substances can be obtained in pure state from their solution by the process of :

• Galvanisation

• Rusting

• Crystallisation