Answer:

Question 1

State True or False

(a) Evaporation of WATER is a reversible change.

(b) Burning of the candle is an irreversible change.

(c) Rusting of iron is a reversible change.

(d) Bursting of cracker is fast change.

(e) Formation of Petrol is a slow change.

(F) Baking of dough into bread is a reversible change.

Question 2

Fill in the Blank

1. Generally on heating metals ______ .

2. Paper, petrol, LPG, CNG etc. are _________ substances.

3. A change in which new substance is formed is called __________.

4. A change that occurs during a definite time interval is known as _________.

5. ______ is the process Heating of milk for boiling to kill microbes.

6. Dissolving sugar in water is a ____________.

7. water changes into ice on cooling is an example of _______.

8. Those changes which are DESIRED to occur that is we want them to take place are known _________.

Question 3

Match the column

Column A

Column B

A change in which new substance is formed

Non-periodic change

Changes in which physical properties like shape, size and state changes without formation of new substance

Slow change

Those changes which take place in a long period of time

Undesirable changes

Those changes which we do not want to take place

Chemical changes

A change that does not repeat again and again after a regular interval of time

Physical changes

Burning of fuel is a

Irreversible change

Crossword

Solve the below crossword

Across

6. Changing of water vapour into water

7. Changing of water into gas on heating

Down

1. The burning of fuel on heating

2. Changing of ice into water on heating

3. drying of clothes is a

4. change of substance from liquid to solid state

5. Bursting of balloon is

6. cooking of food is a

Answer 1

True

True

False

True

True

False

Answer 2

expands

Inflammable

Chemical changes

Periodic changes

pasteurization

Reversible change

Reversible change

Desirables changes

Column A

Column B

A change in which new substance is formed

Chemical changes

Changes in which physical properties like shape, size and state changes without formation of new substance

Physical changes

Those changes which take place in a long period of time

Slow changes

Those changes which we do not want to take place

Undesirable changes

A change that does not repeat again and again after a regular interval of time

Non-periodic change

Burning of fuel is a

Irreversible change

Explanation: