NCERT –CLASS 7 CHAPTER 6-physical and chemical changes

Multiple Choice

1. A change in a substance's physical qualities is referred to as

• Chemical change

• Both physical and chemical change

• Physical change

• None of the above

​

A change in a substance's physical qualities is referred to as physical change

Multiple Choice

2. Consider the following statements

1. Size, shape, colour, and condition of a substance are all examples of chemical attributes.

2. Because no new substance is generated, most physical changes are reversible.

Which of the statements given above is/are correct?

• 1 only

• 2 only

• Both 1 and 2

• Neither 1 nor 2

​

·    Size, shape, colour, and condition of a substance are all examples of physical attributes.

· Because no new substance is generated, most physical changes are reversible. The substance is the same, but the physical qualities have altered

Multiple Choice

3. Consider the following statements

1. A chemical change usually involves a chemical process that produces new products.

2. In chemical change the substances are same, but usually physical qualities are altered

Which of the statements given above is/are correct?

• 1 only

• 2 only

• Both 1 and 2

• Neither 1 nor 2

​• A chemical change usually involves a chemical process that produces new products. • In a physical change the substances are same, but the physical qualities are altered

Multiple Choice

4. Which of the following are the examples of chemical change?

1. Iron rusting

2. Burning of wood

3. Beating of aluminum for making aluminum foil

4. Photosynthesis

Select the correct answer using the code given below

• 1 and 2

•  2 and 3

• 1, 2 and 4

• All of the above

​

Chemical changes

1. Iron rusting

2. Burning of wood

3. Photosynthesis

Beating of aluminum for making aluminum foil is a an example of physical change

Multiple Choice

5. Consider the following statements

1. Despite the fact that a substance's molecules are rearranged when it experiences a physical change, its composition remains the same.

2. A substance's molecular composition is completely altered when it experiences a chemical transformation.

3. Chemical changes result in the production of new substances.

Which of the statements given above is/are correct?

• 1 and 2

• 2 and 3

• 1, 2 and 3

• 1 and 3

​

·    Despite the fact that a substance's molecules are rearranged when it experiences a physical change, its composition remains the same.

·    A substance's molecular composition is completely altered when it experiences a chemical transformation.

·    Chemical changes result in the production of new substances.

Multiple Choice

6. Which of the following are the examples of physical change

1. Dissolving sugar in water

2. Melting of wax

3. Freezing of water

Select the correct answer using the code given below

• 1 and 2

• 2 and 3

• 1, 2 and 3

• 1 and 3

​

Some examples of physical change are freezing of water, melting of wax, boiling of water, etc.

Multiple Choice

7. Consider the following statements:

1. Cutting a log of wood into small pieces is an example of physical change.

2 .Formation of manure from leaves is a chemical change

Which of the statements given above is/are correct?

• 1 only

• 2 only

• Both 1 and 2

• Neither 1 nor 2

​

·    Cutting a log of wood into small pieces is an example of physical change.

·    Formation of manure from leaves is a chemical change

Multiple Choice

8. Which of the following is not an example of chemical change?

• Bursting of a firework

• Seed germination

• Coal production from buried trees

• Breaking a glass

​

·    Breaking a glass is an example of chemical change

·    Bursting of firework, seed germination , coal production from buried trees are examples of chemical change

 

Multiple Choice

9. Which of the following is a rust-prevention method?

• Crystallization

• Galvanization

• Chemical reaction

• Physical alteration

​

·    Galvanization, often known as galvanization is the process of putting a protective zinc coating on iron or steel to prevent rusting.

·    The most popular procedure is hot dip galvanizing, which involves immersing steel parts in molten zinc.

Multiple Choice

10. Which of the following is the chemical name of rust?

• Ferric oxide

• Calcium carbonate

• Ascetic acid

• None of the above

​

·    Rust is a broad word for a group of iron oxides, most of which are red oxides, created by the interaction of iron with oxygen in the presence of water or air moisture.

·    Rust has the chemical formula Fe 2 O 3, which is known as iron oxide but is also known as ferric oxide.

Multiple Choice

11. What happens when carbon dioxide gas passes through lime water?

1 The lime water turns milky

2. The formation of calcium carbonate

3.The formation of ferric oxide

Select the correct answer using the code given below

• 1 and 2

• 2 and 3

• 2 and 3

• 1 and 3

​

When carbon dioxide is transported through lime water, it turns milky due to the development of white precipitate in the form of calcium carbonate.

Multiple Choice

12. The following facts are associated with an iron pillar near Delhi's Qutub Minar. Which of these facts is to blame for its long-term stability?

• Even after such a long time, it has not corroded.

• It is less than 10 meter height

• It’s weight about 6000 kg

• None of the above

​

Other metals are blended with iron to create a rust-resistant composition. As a result, the Qutub Miner’s iron pillars have not rusted for a long period.

Multiple Choice

13. Galvanization is a procedure used to prevent reaction of which metal?

• Iron

• Copper

• Zinc

• Aluminum

​

Galvanization is a method of preventing iron from rusting. In this technique, we put a layer of 'zinc' to the surface of the iron.

Multiple Choice

14. Consider the following pairs

1. Rust: Ascetic oxide

 

2. Vinegar: Ferric oxide

 3. Baking soda: Sodium hydrogen carbonate

4. Lime water: Calcium hydroxide

Which of the pair given above is/are correct?

• 1 and 2

• 3 and 4

• 1, 2 and 3

• All of the above

​

1. Rust: Ferric oxide

2. Vinegar: Ascetic oxide

3. Baking soda: Sodium hydrogen carbonate

4. Lime water: Calcium hydroxide

Multiple Choice

15. Changes that result in the production of new compounds are referred to as

• Physical change

• Chemical change

• Both physical and chemical change

• None of the above

​

Changes that result in the production of new compounds are referred to as chemical change

Multiple Choice

16. Rusting of iron is faster in which of the following regions?

• Coastal region

• Desert region

• Temperate region

• None of the above

​

Contact with water (moisture) and oxygen is required for iron to rust. Because the humidity in coastal locations is higher than in deserts, iron things rust faster in coastal areas than in deserts.

Multiple Choice

17. The method of obtaining large crystals of pure material is known as

• Crystallization

• Galvanization

• Chemical reaction

• Rusting

​

The method of obtaining large crystals of pure material is known as crystallization

Multiple Choice

18. Consider the following statements

1. The cooking rice is a chemical transformation

2. Volcanic eruption is a permanent change that cannot be reversed.

3. Cloud formation is not  a reversible process.

Which of the statements given above is/are correct?

• 1 and 2

• 2 and 3

• 1, 2 and 3

• 1 and 3

​

·    The cooking rice is a chemical transformation

·    Volcanic eruption is a permanent change that cannot be reversed.

·    Cloud formation is a reversible process.

Multiple Choice

19. Consider the following statements

1. Rusting requires the presence of both oxygen and water.

2. New chemicals are created as a result of chemical reactions.

Which of the statements given above is/are correct?

• 1 only

• 2 only

• Both 1 and 2

• Neither 1 nor 2

​

·    Rusting requires the presence of both oxygen and water.

·    New chemicals are created as a result of chemical reactions

Multiple Choice

20. Which of the following are the physical properties of substances?

1. Size

2. Shape

3. Colour

4.Acidity

Select the correct answer using the code given below

• 1 and 2

• 2 and 3

• 1, 2 and 3

• All of the above

​

·    Physical properties of a substances are size , shape and colour

·    Acidity is a chemical change of a substance

 

Multiple Choice

21. The process of putting a zinc layer atop iron is referred to as

• Galvanization

• Crystallization

• Calcination

• None of the above

​

The process of putting a zinc layer atop iron is referred to as Galvanization

Multiple Choice

22.  When a substance's chemical qualities remain unchanged but its appearance or shape changes, this is called a

 

• Physical change

• chemical change

• both chemical and physical change

• Galvanization

​

When a substance's chemical qualities remain unchanged but its appearance or shape changes, this is called a physical change

Multiple Choice

23. Consider the following statements.

1. When calcium carbonate decomposes, calcium oxide and carbon dioxide are produced.

2. Magnesium oxide is basic in nature

Which of the statements given above is/are not correct?

• 1 only

• 2 only

• Both 1 and 2

• Neither 1 nor 2

​

·    When calcium carbonate decomposes, calcium oxide and carbon dioxide are produced.

· Magnesium oxide is basic in nature

Multiple Choice

24. Whic of the following are the methods to prevent rusting of iron?

1. Galvanization

2. Greasing

3.Painting

4.Oxidation reaction

Select the correct answer using the code given above is/are correct

• 1 and 2

• 2 and 3

• 1, 2 and 3

• All of the above

​Methods to prevent rusting of iron 1.Galvanisation

2.Greacing

3.Painting

Rusting is an oxidizing reaction

Multiple Choice

25.  Consider the following statements

1. Physical change is a temporary change

2.In a physical change there is no substances are formed

3.A chemical change is a permanent change

 

Which of the statements given above is / are correct?

• 1 and 2

• 2 and 3

• 1, 2 and 3

• 1 and 3

​

·    Physical change is a temporary change

·    A chemical change is a permanent change

·    In a physical change there is no substances are formed

·    A chemical change is a permanent change

Multiple Choice

26. Consider the following statements.

1. The process of photosynthesis is chemical change

2. Evolution of gas may be occur during chemical change

 

Which of the statements given above is/are correct?

• 1 only

• 2 only

• Both 1 and 2

• Neither  1 not 2

​

·    The process of photosynthesis is chemical change

Evolution of gas may be occur during chemical change

Multiple Choice

27. What is the chemical name of Baking Soda?

• Sodium hydrogen carbonate

• Calcium hydroxide

• Ascetic acid

​

Sodium bicarbonate or sodium hydrogen carbonate are the chemical names for baking soda.

Multiple Choice

28.Which of the statements :

1. Iron pipes that have been zinc-coated do not corrode quickly.

2.Steam condensation isn't a chemical transformation.

Which of the statements given above is/are correct?

• 1 only

• 2 only

• Both 1 and 2

• Neither 1 not 2

​

·    Iron pipes that have been zinc-coated do not corrode quickly.

·    Steam condensation isn't a chemical change

Multiple Choice

29. The formation of a gas occurs when baking soda and lemon juice are mixed. What type of change is it?

• Chemical change

• physical change

• Biological change

• None of the above

​

The formation of a gas occurs when baking soda and lemon juice are mixed- it is an example of chemical change

Multiple Choice

30. Consider the following statements

1. A chemical change may involve change in colour, temperature, and smell or evolution of gas

2. Because curd cannot be converted back to milk, the formation of curd involves a chemical change. Which of the statements given above is are not correct?

• 1 only

• 2 only

• Both 1 and 2

• Neither 1 nor 2

​

·    A chemical change may involve change in colour, temperature, and smell or evolution of gas

·    Milk and curd have different characteristics.3.