Physical and Chemical Changes: Rusting, Galvanization

When a candle burns both physical and chemical change take place Anaerobic bacteria digest animal waste and produce biogas Ships suffer a lot of damage though they are not painted Stretching of rubber band is not a physical change Rusting of iron Combustion of magnesium ribbon Burning of candle Melting of wax Change in colour only Change in temperature only Evolution of gas only All of these Rusting is a chemical change because a new substance is formed Beating of Aluminium metal to make Aluminium foil, is a physical change Digestion of food is a chemical change All the above It is more than 7 metre height It weighs about 6000 kg It was built more than 1600 years ago It has no rust after such long period Fe2O3 Fe3O4 FeO None of these By crystallization By chromatography By peptization By all these methods Crystallization Sedimentation Galvanisation None of these Bursting of a fire cracker Germination of seed Coal formation from buried trees All of these In physical change In chemical change In both (a) and (b) In neither of these Iron Zinc Aluminium Copper It is more than 7 metres high It weighs about 6000 kg It was built more than 1600 years ago It has not rusted after such a long period

Physical change that can be reversed

Chemical change that can be reversed

Physical change that cannot be reversed

Chemical change that cannot be reversed

The body of ship is always in contact with water.

The air around the ship is humid.

Presence of salts in sea water speed up the process of rusting.

All of the above

Evolution of gas

Change in colour

Change in taste

All of these

Physical change

Chemical change

Both (a) and (b)

None of these

Galvanisation

Neutralisation

Crystallisation

All of these

Preventing iron from coming in contact with air and moisture by applying greese or paint

Deposit a layer of a metal like chromium or zinc on iron

Both (a) and (b)

None of these

Galvanisation

Neutralisation

Crystallisation

None of these

Sea water contains many salts

Sea water is bitter

Sea water is sour

Sea water is sweet