Pick the change that can be reversed from the following.

1

(a)

Cutting of trees

(b)

Melting of ghee

(c)

Burning of candle

(d)

Blooming of flower

Which of the following changes cannot be reversed?

1

(a)

Hardening of cement

(b)

Freezing of ice cream

(c)

Opening a door

(d)

Melting of chocolate

An iron ring is heated. Which of the following statements about it is incorrect?

1

(a)

The ring expands

(b)

The ring almost comes to the same size on cooling

(c)

The change in this case is reversed

(d)

The ring changes its shape and the change cannot be reversed

Salt can be separated from its solution (salt dissolved in water) because

1

(a)

mixing of salt in water is a change that can be reversed by heating and melting of salt

(b)

mixing of salt in water is a change that cannot be reversed

(c)

mixing of salt-in water is a permanent change

(d)

mixing of salt in water is a change that can be reversed by evaporation

Which one of the steps while burning a candle is not reversible?

1

(a)

Melting of solid wax

(b)

Wax vapour burn into flame

(c)

Liquid wax changes into vapours

(d)

All of the above

Which is a way to make a change happen?

1

(a)

Heating of substance

(b)

Mixing of substance with another substance

(c)

Cooling of substance

(d)

All of the above

Pick the change that can be reversed from the following:

1

(a)

Cutting of trees

(b)

Melting of ghee

(c)

Burning of candle

(d)

Blooming of flower

Which of the following changes can not be reversed?

1

(a)

Hardening of cement

(b)

Freezing of ice cream

(c)

Opening a door

(d)

Melting of chocolate

An iron ring is heated. Which of the following statements about it is incorrect?

1

(a)

The ring expands

(b)

The ring almost comes to the same size on cooling

(c)

The change in this case is reversed

(d)

The ring changes its shape and the change can not be reversed

Salt can be separated from its solution (salt dissolved in water), because:

1

(a)

Mixing of salt in water is a change that can be reversed by heating and melting of salt

(b)

Mixing of salt in water is a change that can not be reversed

(c)

Mixing of salt in water is a permanent change

(d)

Mixing of salt in water is a change that can be reversed by evaporation

Dry grass or scrap of paper burns____________ than a log of wood.

1

(a)

faster

Growth of a plant is ___________change.

1

(a)

irreversible

In chemical change, constituents lead to the formation of new ____

1

(a)

product

________ of iron is an irreversible change.

1

(a)

Rusting

Freezing of water is an example of _______

1

(a)

reversible change

Reversible change is a permanent change.

1

(a) True

(b) False

A balloon increases in size when filled with air.

1

(a) False

(b) True

A potato remains a potato even after it is cooked. Hence, cooking is a physical change.

1

(a) True

(b) False

Souring of milk is a reversible change.

1

(a) True

(b) False

Salt can be obtained from sea water by the process of evaporation

1

(a) False

(b) True

A cement bag left open gets hard after some time, what type of change it is ?

1

(a)

Chemical change.

Is boiling of an egg a physical or a chemical change?

1

(a)

Name two changes in yourself that you face every day.

1

(a)

(a) Daily hair growth.
(b) Daily nail growth

How can you say that pickling of lemon is a desirable change?

1

(a)

Pickle adds taste to our food. Hence, pickling of lemon is a desirable change.

Melting of wax is an irreversible change. Is it correct?

1

(a)

No, it is not correct because melting wax becomes solid again on cooling.