Which of the following is a physical change?

1

(a)

Rusting of iron

(b)

Combustion of magnesium ribbon

(c)

Burning of candle

(d)

Melting of wax

A chemical change may involve

1

(a)

change in colour only

(b)

change in temperature only

(c)

evolution of gas only

(d)

All of the above

Galvanisation is a process used to prevent the rusting of which of the following?

1

(a)

Iron

(b)

Zinc

(c)

Aluminium

(d)

Copper

What is the formula of rust?

1

(a)

Fe₃O₄

(b)

Fe₂O₃

(c)

FeO

(d)

None of these

Which one is a chemical change?

1

(a)

Burning of paper

(b)

Germination of seed

(c)

Formation of coal from wood

(d)

All of these

A physical change is generally _________

1

(a)

reversible

Grinding of wheat grain changes its size. It is a __________ change

1

(a)

physical

Iron benches kept in lawns and gardens get __________ It is a _______change because a new ________ is formed.

1

(a)

rusted, chemical, substance

Oxygen and _____________are must for rusting

1

(a)

water (Moisture)

A reversible change is a__________ change

1

(a)

physical

Condensation of steam is not a chemical change.

1

(a) False

(b) True

When a candle burns, both physical and chemical changes take place.

1

(a) False

(b) True

Anaerobic bacteria digest animal wastes and produce biogas.

1

(a) False

(b) True

Ships suffer a lot of damage though they are painted.

1

(a) False

(b) True

Stretching of rubber band is not a physical change.

1

(a) True

(b) False

Obviously, you cannot join the pieces back to make the original piece, but is there a change in the property of the paper?

1

(a)

No, no change takes place in the property of the paper

Did you recover chalk from the dust?

1

(a)

No

What are the two main kinds of changes?

1

(a)

There are two kinds of changes:
(i) Physical changes,
(ii) Chemical changes

If you cut off a paper into various pieces, is there any change in the property of the paper?

1

(a)

No, there is no change in the chemical property of paper.

Give two examples of physical change

1

(a)

(i) Melting of ice (ii) Boiling of water