NCERT Class 7 Science Chapter 6 Physical and Chemical Changes Extra Questions

NCERT Class 7 Science Chapter 6 Physical and Chemical Changes Extra Questions and Answers

Class 7 Science Chapter 6 Extra Questions and Answers – Physical and Chemical Changes. Here in this Page Class VII Students can Learn Extra Questions & Answer 6th Chapter Science fully Inside.

We Provided Here Physical and Chemical Changes Science Chapter 6 Long Answer Type Question, Very Short Type Questions (VSA) / MCQ Type Questions, Short Type Questions (SA).

Class 7 Science Chapter 6 Extra Question with Answer – Physical and Chemical Changes

Science Chapter 6 Physical and Chemical Changes Class 7 Inside 5 Marks, 3 marks, 2 Marks & And 1 Marks Important Questions and Answers.

1) Fill in the blanks:

a) Explosion of a firework is a ___ change.(Chemical)

b) The chemical name of vinegar is ____.(Acetic acid)

c) ____ turned lime water milky.(Carbon dioxide)

d) Water changed its state is a ___ change. (Physical)

2) Multiple choice questions:

a) The chemical name of baking soda is ____?

a) Sodium hydrogencarbonate b) Acetic acid

Ans. a) Sodium hydrogen carbonate

b) The hack-saw blade changed color on heating is a ___ change?

a) Chemical b) physical

Ans. b) Physical

c) In ___ changes new substances are produced?

a) Chemical b) physical

Ans. a) Chemical

d) To prevent rusting of iron by depositing a layer of ___ on iron?

a) Zinc b) Copper

Ans. a) Zinc

3) Answer the following questions:

a) What is physical change? Give an example.

Ans. A change in which a substance undergoes a change in its physical properties is called physical change.

Example – Chopping wood.

b) What is galvanization? Explain why a fraction of ship’s iron has to be replaced every year?

Ans. The process of depositing a layer of zinc on iron is called galvanization.

Ships are made of iron and a part of them remains under water. On the part above water also, water drops keep clinging to the ship’s outer surface. Moreover, the water of the sea contains many salts. The salt water makes the process of rust formation faster. Therefore, ships suffer a lot of damage from rusting in spite of being painted. So, a fraction of ship’s iron has to be replaced every year.

 

In case you are missed :- NCERT Extra Questions for Acids, Bases and Salts

 

c) Explain why stainless steel does not rust? Which type of change the rusting of iron is?

Ans. Stainless steel is made by mixing iron with carbon and metal like chromium, nickel and manganese. So, it does not rust.

The rusting of iron is a chemical change.

4) Match the following:

            Column I                                                                           Column II

a) Physical property 1) In physical change

b) Chemical change 2) The presence of both oxygen and water is essential.

c) Physical change 3)  State of a substance

d) No new substance is formed 4) Magnesium ribbon burning

e) For rusting 5) Melting an ice cube

Ans. a) – 3), b) – 4), c) – 5), d) –1), e) – 2)

5) Mark your answer as per the codes provide below:

a) A: Burning of log of wood is a chemical change.

R:) Burning of log of wood leads to the formation of ash, smoke.

I.) Both A and R are true and R is the correct explanation of A.

II.) Both A and R are true but R is not the correct explanation of A.

III.) A is true but R is false.

IV.) A is false but R is true.

V.) Both A and R are false.

Ans. I. Both A and R are true and R is the correct explanation of A.

b) A: Chopping wood is a chemical change.

R: No new substance is formed during chopping wood.

I.) Both A and R are true and R is the correct explanation of A.

II.) Both A and R are true but R is not the correct explanation of A.

III.) A is true but R is false.

IV.) A is false but R is true.

V.) Both A and R are false.

Ans. IV. A is false but R is true.

6) The salt obtained by the evaporation of sea water, is not pure and the shape of its crystals cannot be seen clearly. However, large crystals of pure substances can be formed from their solutions. This process is called crystallization. It is an example of physical change.

a) What is crystallization?

Ans. The process of forming large crystals of pure substances from their solution is called Crystallization.

b) Crystallization is a _____ change. (Physical)

In case you are missed :- NCERT Extra Questions for Nutrition in Plants

Updated: April 6, 2023 — 11:28 am

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