NCERT Solutions for Class 7 Science Chapter 6: Physical and Chemical Changes

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NCERT Solutions for Class 7 Science Chapter 6 Physical and Chemical Changes are provided in the article below. The important topics covered in this chapter are:

Physical changes
Chemical changes
Rusting of iron
Crystallization

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NCERT Solutions for Class 7 Science Chapter 6

NCERT Solutions for Class 7 Science Chapter 6 Physical and Chemical Changes are given below:

Class 7 Science Chapter 6 Physical and Chemical Changes: Important Topics

A Physical change is a temporary change that affects only physical properties such as shape, and size. It is said that, whenever a substance goes through a physical change, its composition remains the as it is despite its molecules being rearranged. A chemical change is a permanent change having both physical and chemical properties of a substance. It is said that whenever a substance goes through a chemical change, its molecular composition is completely changed.

Physical changes

Physical changes are defined as the changes affecting the form of a chemical substance, but not it is chemical composition. Physical changes are generally used to separate mixtures into their component compounds, but can not be used to separate compounds into chemical elements or simpler compounds.

Chemical changes

Chemical changes take place when a substance combines with another in order to form a new substance, called chemical synthesis or, alternatively, chemical decomposition into two or more different substances. These processes are known as chemical reactions which, in general, are not reversible except by further chemical reactions.

Rusting of iron

Rusting of iron is an oxidation reaction. The iron reacts with water and oxygen in order to form hydrated iron(III) oxide, which we perceive as rust. Iron and steel rust when they come into contact with water and oxygen – both are needed for rusting to occur.

Chapter Related Links:

Difference Between Physical and Chemical Changes	Chemical change	Difference between physical and chemical properties
Oxygen Cycle	Examples of Weak Acids	Noble Gases
Weak Base	Difference Between Acid and Base	Solvent Examples

Class 7 Science Additional Resources:

CBSE Class 7 Science NCERT Textbook	CBSE Class 7 Science Sample Paper	NCERT Solutions

CBSE X Related Questions

1.
When you look at an object very close to your eyes, the:

Ciliary muscles of your eye contract and the eye lens becomes thick.
Ciliary muscles of your eye get relaxed and the eye lens becomes thick.
Ciliary muscles of your eye contract and the eye lens becomes thin.
Ciliary muscles of your eye get relaxed and the eye lens becomes thin.

View Solution

2.
How does the change in curvature of the eye lens help us in the process of seeing the nearby objects clearly?

View Solution

3.
Sex is determined by different factors in various species. However, in human beings, it is determined genetically. Which amongst the following option(s) is/are correct for human beings ?
Gamete carrying X chromosome from female parent.
Gamete carrying X chromosome from male parent.
Gamete carrying Y chromosome from male parent.

(ii) and (iii)
(i) only
(i) and (iii)
(iii) only

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4.
(a) Study the given electric circuit in which 2 A electric current is flowing between points X and Y.

(i) Using the battery, key, voltmeter and ammeter in this given electric circuit, redraw a circuit diagram in which 2 \(\Omega\) and 4 \(\Omega\) resistors are connected between X and Y in parallel combination.
(ii) Circuit drawn by you, in which resistors are connected in parallel combination, calculate the electric current flowing through 4 \(\Omega\) resistor.

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5.
How many bulbs of resistance \( 8 \ \Omega \) each should be connected in parallel combination to draw a current of \( 2 \text{ A} \) from a battery of \( 4 \text{ V} \) ?

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6.
A convex lens of focal length 15 cm, is forming a real image. If the size of image is same as the size of object, then position of object and position of image will be, respectively :

\(-15 \, \text{cm and} -15 \, \text{cm from lens}\)
\(-15 \, \text{cm and} +15 \, \text{cm from lens}\)
\(-30 \, \text{cm and} +30 \, \text{cm from lens}\)
\(-30 \, \text{cm and} -30 \, \text{cm from lens}\)

View Solution

NCERT Solutions for Class 7 Science Chapter 6: Physical and Chemical Changes

NCERT Solutions for Class 7 Science Chapter 6

Class 7 Science Chapter 6 Physical and Chemical Changes: Important Topics

Physical changes

Chemical changes

Rusting of iron

CBSE X Related Questions

1.
When you look at an object very close to your eyes, the:

2.
How does the change in curvature of the eye lens help us in the process of seeing the nearby objects clearly?

5.
How many bulbs of resistance \( 8 \ \Omega \) each should be connected in parallel combination to draw a current of \( 2 \text{ A} \) from a battery of \( 4 \text{ V} \) ?

6.
A convex lens of focal length 15 cm, is forming a real image. If the size of image is same as the size of object, then position of object and position of image will be, respectively :

Similar Science Concepts

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NCERT Solutions for Class 7 Science Chapter 6: Physical and Chemical Changes

NCERT Solutions for Class 7 Science Chapter 6

Class 7 Science Chapter 6 Physical and Chemical Changes: Important Topics

Physical changes

Chemical changes

Rusting of iron

CBSE X Related Questions

1.When you look at an object very close to your eyes, the:

2. How does the change in curvature of the eye lens help us in the process of seeing the nearby objects clearly?

5.How many bulbs of resistance \( 8 \ \Omega \) each should be connected in parallel combination to draw a current of \( 2 \text{ A} \) from a battery of \( 4 \text{ V} \) ?

6.A convex lens of focal length 15 cm, is forming a real image. If the size of image is same as the size of object, then position of object and position of image will be, respectively :

Similar Science Concepts

Comments

SUBSCRIBE TO OUR NEWS LETTER

1.
When you look at an object very close to your eyes, the:

2.
How does the change in curvature of the eye lens help us in the process of seeing the nearby objects clearly?

5.
How many bulbs of resistance \( 8 \ \Omega \) each should be connected in parallel combination to draw a current of \( 2 \text{ A} \) from a battery of \( 4 \text{ V} \) ?

6.
A convex lens of focal length 15 cm, is forming a real image. If the size of image is same as the size of object, then position of object and position of image will be, respectively :