When a woolen yarn is knitted to get a sweater, the change can be classified as _______ .

________is an example of a periodic change.

_________ is not a chemical change.

Filling up a balloon with hot air is a _____ change.

Opening a gas cylinder knob converts _____ fuel into ________ fuel. This is an example of _____ change.

Respiration is a ______ change.

Cutting of cloth is an example of a periodic change.

Taking a glass of water and freezing it by placing it in the freezer is a chemical change.

A bean plant collecting sunlight and turning it into bean seeds is an example of physical and non-periodic change.

Tarnishing of silver is an example of endothermic change.

Assertion: The process of conversion of liquid water to its vapours by heating the liquid is called boiling.
Reason: The process of conversion of water vapours to liquid by cooling the vapours is called condensation.
a. Both A and R are true and R is the correct explanation of A.
b. Both A and R are true but R is not the correct explanation of A.
c. A is true but R is false.
d. A is false but R is true.

Assertion: Burning of wood log to charcoal is a physical change.
Reason: The products formed of burning a piece of wood can be easily converted back to wood log.
a. Both A and R are true and R is the correct explanation of A.
b. Both A and R are true but R is not the correct explanation of A.
c. A is true but R is false.
d. A is false but R is true.
e. A and R are false.

Physical Change : Boiling :: Chemical Change : ________.

Wood to saw dust :_________ :: Wood to Ash : Chemical change

State two examples of periodic changes.

Cold milk is heated and it becomes hot. Which type of change it is?

What type of change is colouring of a paper?

What type of energy changes is associated when ice melts?

Distinguish physical and chemical changes.

How can a change occur in a substance?

What is the difference between dissolution of sugar and burning of sugar?

Explain the following statement: Digestion is a chemical change.

How the iron blade is fixed into a wooden handle in tools used to dig the soil?

Boiling of water is a physical change; but boiling of egg is a chemical change. Why?