Careers360 Logo
School
Search Colleges, Exams, Schools & more
NCERT Solutions for Class 7 Science Chapter 5 Physical and Chemical Changes

NCERT Solutions for Class 7 Science Chapter 5 Physical and Chemical Changes

Edited By Shivani Poonia | Updated on Apr 29, 2025 02:07 PM IST

In our everyday lives, we often see various types of changes occurring. Some changes are permanent and irreversible, while others are temporary and reversible. The NCERT Chapter 5 Science class 7 has a detailed discussion on the two main types of changes, chemical changes (which involve a transformation where new substances are formed). For example, rusting of iron and physical changes (the substance's state changes, but its chemical composition remains the same), melting of ice into water etc. This chapter also includes how to identify these changes and understand the processes and how these changes are essential to many man-made and natural processes.

This Story also Contains
  1. Free download physical and chemical changes class 7 solutions PDF for CBSE exam.
  2. Download PDF
  3. NCERT Solutions for Class 7 Science Chapter 5 Physical And Chemical Changes: Exercise Solutions
  4. Chapterwise NCERT Solutions of Class 7 Science
  5. Physical And Chemical Changes Class 7 Chapter 5-Topics
  6. Important terms to be remembered :
  7. Key Features of Class 7: Physical and Chemical Changes

The NCERT solutions for Class 7 Chapter 5 Physical and Chemical Changes are designed by our subject matter experts to offer a structured and systematic approach to these important concepts and help students to develop a clear understanding of complex problems through a series of solved examples, questions, and conceptual explanations. These solutions also add extra value to the resources of the students to enhance their performance in board exams as well as in competitive exams. Our subject experts ensure that through content provided below, students can gain maximum knowledge of the chapter.

**As per the CBSE Syllabus 2025-26, this chapter has been renumbered as Chapter 5 in Class 7 Science.

Free download physical and chemical changes class 7 solutions PDF for CBSE exam.

Download PDF

NCERT Solutions for Class 7 Science Chapter 5 Physical And Chemical Changes: Exercise Solutions

1. Classify the changes involved in the following processes as physical or chemical changes:

(a) Photosynthesis

Answer:

(a) Photosynthesis is a chemical change.

1. Classify the changes involved in the following processes as physical or chemical changes:

(b) Dissolving sugar in water

Answer:

(b) Dissolving sugar in water is a physical change.

1. Classify the changes involved in the following processes as physical or chemical changes:

(c) Burning of coal

Answer:

(c) Burning of coal is a chemical change.

1. Classify the changes involved in the following processes as physical or chemical changes:

(d) Melting of wax

Answer:

(d) Melting of wax is a physical change.

1. Classify the changes involved in the following processes as physical or chemical changes:

(e) Beating aluminium to make aluminium foil

Answer:

(e) Beating aluminium to make aluminium foil is a physical change.

1. Classify the changes involved in the following processes as physical or chemical changes:

(f ) Digestion of food

Answer:

Digestion of food is a chemical change.

During digestion, enzymes in the stomach and intestines break down food molecules into simpler molecules.

2. State whether the following statements are true or false. In case a statement is false, write the corrected statement in your notebook.

(a) Cutting a log of wood into pieces is a chemical change. (True/False)

(b) Formation of manure from leaves is a physical change. (True/False)

(c) Iron pipes coated with zinc do not rust easily. (True/False)

(d) Iron and rust are the same substances. (True/False)

(e) Condensation of steam is not a chemical change. (True/False)

Answer:

(a) False because cutting a log of wood into pieces is a physical change.

(b) False because the formation of manure from leaves is a chemical change.

(c) True.

(d) False because Iron and rust are different substances.

(e) True

3. Fill in the blanks in the following statements:

(a) When carbon dioxide is passed through lime water, it turns milky due to the formation of _________.

(b) The chemical name of baking soda is _________.

(c) Two methods by which rusting of iron can be prevented are _________ and _________.

(d) Changes in which only _________ properties of a substance change are called physical changes.

(e) Changes in which new substances are formed are called _________ changes.

Answer:

(a) When carbon dioxide is passed through lime water, it turns milky due to the formation of calcium carbonate.

(b) The chemical name of baking soda is sodium hydrogen carbonate.

(c) Two methods by which rusting of iron can be prevented are galvanization and painting.

(d) Changes in which only physical properties of a substance change are called physical changes.

(e) Changes in which new substances are formed are called chemical changes.

4. When baking soda is mixed with lemon juice, bubbles are formed with the evolution of a gas. What type of change is it? Explain.

Answer:

When baking soda is mixed with lemon juice then it is a chemical change, bubbles are formed with the evolution of a carbon dioxide gas.

5. When a candle burns, both physical and chemical changes take place. Identify these changes. Give another example of a familiar process in which both the chemical and physical changes take place.

Answer:

When a candle burns, both physical and chemical changes take place. On heating, candle wax gets melted is a physical change since it again turns into wax on cooling.

The wax gives carbon dioxide, heat, light, water vapour and carbon soot on heating with a state chemical change.

Another example is the lighting of the bulb using a dry cell.

6. How would you show that setting of curd is a chemical change?

Answer:

The setting of curd is a chemical change because the new substance(curd) formed from milk differs in taste and it cannot be converted into milk again i.e. it is irreversible.

7. Explain why burning of wood and cutting it into small pieces are considered as two different types of changes.

Answer:

The burning of wood is a chemical change because wood, after burning, gives carbon dioxide, ash, heat,and water vapour It is also an irreversible process.

Whereas cutting wood into small pieces is a physical change because the original composition of wood remains the same and no new substance is formed.

8. Describe how crystals of copper sulphate are prepared.

Answer:

The crystals of copper sulphate are prepared as follows:

1. A cup of water is taken in a beaker.

2. Add some drops of dilute sulphuric acid in it.

3. Heat it and when it starts boiling, add copper sulphate powder slowly with continuous stirring.

4. The copper sulphate powder is added till the saturation level.

5. Filter the solution and cool it.

6. Leave it undisturbed, and we will observe copper sulphate crystals after some hours.

9. Explain how painting of an iron gate prevents it from rusting.

Answer:

Painting of an iron gate prevents direct contact of iron with water and air(oxygen) which are required for rusting.

No exposure to water and oxygen with iron prevents iron from rusting.

10. Explain why rusting of iron objects is faster in coastal areas than in deserts.

Answer:

Rusting occurs with direct contact of iron with water and oxygen.

In coastal areas, the moisture content is high in the air, which means rusting of iron objects is faster in coastal areas because in deserts, moisture in the air is absent.

11. The gas we use in the kitchen is called liquified petroleum gas (LPG). In the cylinder it exist as a liquid. When it comes out from the cylinder it becomes a gas (Change – A) then it burns (Change – B). The following statements pertain to these changes. Choose the correct one.

(i) Process – A is a chemical change.

(ii) Process B is a chemical change.

(iii) Both processes A and B are chemical changes.

(iv) None of these processes is a chemical change.

Answer:

The gas we use in the kitchen is called liquefied petroleum gas (LPG). In the cylinder, it exists as a liquid. When it comes out from the cylinder it becomes a gas (Change – A) then it burns (Change – B). This is a chemical change.

Thus, option (ii) is correct.

12. Anaerobic bacteria digest animal waste and produce biogas (Change – A). The biogas is then burnt as fuel (Change – B). The following statements pertain to these changes. Choose the correct one.

(i) Process – A is a chemical change.

(ii) Process B is a chemical change.

(iii) Both processes A and B are chemical changes.

(iv) None of these processes is a chemical change.

Answer:

Anaerobic bacteria digest animal waste and produce biogas (Change – A). The biogas is then burnt as fuel (Change – B).

Both processes A and B are chemical change.

Thus, option (iii) is correct.

Class 7 science chapter 5 question answer hold substantial importance in a student's science education. These solutions provide a foundational understanding of the distinctions between physical and chemical changes in matter, which is fundamental in chemistry. Furthermore, the practical relevance of these concepts in daily life, coupled with their significance as a prerequisite for advanced chemistry studies, makes this chapter essential. It also fosters problem-solving skills and prepares students for examinations, making it a crucial component of their science curriculum. In terms of difficulty, the chapter's concepts are explained comprehensively in this article, making it accessible and enabling students to grasp the content effectively.

Chapterwise NCERT Solutions of Class 7 Science

Chapter 1Nutrition in Plants
Chapter 2Nutrition in Animals
Chapter 3Heat
Chapter 4Acids, Bases and Salts
Chapter 5Physical and Chemical Changes
Chapter 6Respiration in Organisms
Chapter 7Transportation in Animals and Plants
Chapter 8Reproduction in Plants
Chapter 9Motion and Time
Chapter 10Electric Current and its Effects
Chapter 11Light
Chapter 12Forests: Our Lifeline
Chapter 13Wastewater Story



Physical And Chemical Changes Class 7 Chapter 5-Topics

  • Physical Changes
  • Chemical Change
  • Rusting Of Iron
  • Crystallisation

NCERT Solutions for Class 7 Subject Wise

NCERT Solutions for Class 7 Maths
NCERT Solutions for Class 7 Science

Important terms to be remembered :

The main terms to be memorised after going through the chapter and also NCERT solutions for Class 7 Science chapter 5 Physical and Chemical Changes, are listed below.

  • Crystallisation: The process of forming large crystals of pure substances is known as crystallisation.
  • Rusting of iron: If iron is kept in moist air, a brownish film is formed on the iron. The brownish substance is called rust, and the process is called rusting.
  • Galvanisation: In the NCERT Class 7 book, the given definition is- Galvanisation is the process of depositing a layer of zinc on iron. Galvanisation prevents iron from rusting.

Key Features of Class 7: Physical and Chemical Changes

  1. Comprehensive Coverage: The physical and chemical changes class 7 solutions cover all topics and concepts related to physical and chemical changes, ensuring a thorough understanding of the chapter.

  2. Clear Explanations: The physical and chemical changes class 7 ncert solutions provide clear and concise explanations, making complex concepts easy to grasp for students.

  3. Step-by-Step Approach: They follow a step-by-step approach, breaking down the Class 7 science chapter 6 question answer and problem-solving processes into manageable steps.

  4. Illustrations and Examples: The Class 7 science chapter 5 Ncert solutions include illustrations and examples to aid in visualization and better comprehension of concepts.

  5. Relevance: The Class 7 physical and chemical changes NCERT solutions highlight the practical relevance of physical and chemical changes in daily life, fostering a deeper connection to the subject matter.

  6. Exam-Oriented: They are designed to assist students in preparing for examinations, with physical and chemical changes class 7 questions and answers to typical questions that may appear in tests and exams.

  7. Language Clarity: The language used in the solutions is student-friendly, ensuring that students can follow along and learn independently.

  8. Accessible: The class 7 science chapter 5 question answers are readily available in printed and digital formats, making them easily accessible to all students.

  9. Alignment with NCERT Curriculum: The science chapter 5 class 7 solutions are closely aligned with the NCERT curriculum, ensuring consistency with what is taught in classrooms.

These features collectively make Class 7 NCERT solutions for "Physical and Chemical Changes" an invaluable resource for students to master the chapter effectively.

Also, check the NCERT Books and the NCERT Syllabus here



Frequently Asked Questions (FAQs)

1. Is baking a cake a physical or chemical change?

Baking a cake involves both physical and chemical changes. It's primarily a chemical change. When heated, the ingredients undergo chemical reactions, forming new compounds that give the cake its texture and flavor. However, there are also physical changes, like the mixing of ingredients.

2. What are the key differences between chemical and physical changes?

Chemical Change: Difficult or impossible to reverse, Production of a gas (bubbles, fizzing, smoke), Formation of a precipitate (a solid forming in a liquid solution), Color change (unexpected and significant), Temperature change (getting hotter or colder without external heating/cooling), Production of light or sound.

 Physical Change: Change in size or shape, State change (solid, liquid, gas), Dissolving (sometimes, see specific dissolving examples below), Easily reversible (often, but not always).

3. Is physical change always reversible?

Generally, but not always. Some physical changes can be reversed easily (e.g., freezing water, melting ice), but some physical changes are difficult to reverse (e.g., grinding a rock into powder).

4. What is the main difference between a physical change and a chemical change?

Physical change involves the physical state of a substance, but it doesn't change its chemical composition. It means the substance is still the same material, while in a Chemical change, a new substance is transformed with a different chemical composition and properties. It means the substance does not remain the same in this change.


5. Can a change be both physical and chemical?

A change can be both physical and chemical. For example, when you burn wood, the wood undergoes both chemical changes and physical changes. Combustion of wood, creating new substances (ash, gases, etc.), is a chemical change. Simultaneously, the wood undergoes in shape, size, and state; this is a physical change.

6. How can I tell if a change is physical or chemical? What are some clues?

Here are some clues to help you determine the type of change:

  • Clues for Chemical Change: Difficult or impossible to reverse, Production of a gas (bubbles, fizzing, smoke), Formation of a precipitate (a solid forming in a liquid solution), Color change (unexpected and significant), Temperature change (getting hotter or colder without external heating/cooling), Production of light or sound.

Clues for Physical Change: Change in size or shape, State change (solid, liquid, gas), Dissolving (sometimes, see specific dissolving examples below), Easily reversible (often, but not always).

Also Read

Articles

Upcoming School Exams

National Institute of Open Schooling 10th examination

Admit Card Date:02 April,2025 - 19 May,2025

National Institute of Open Schooling 12th Examination

Admit Card Date:02 April,2025 - 19 May,2025

Goa Board Higher Secondary School Certificate Examination

Admit Card Date:17 April,2025 - 17 May,2025

Meghalaya Board of Secondary School Leaving Certificate Examination

Exam Date:01 May,2025 - 08 May,2025

Meghalaya Board of Higher Secondary School Leaving Certificate Examination

Result Date:05 May,2025 - 05 May,2025

View All School Exams

Popular Questions

A block of mass 0.50 kg is moving with a speed of 2.00 ms-1 on a smooth surface. It strikes another mass of 1.00 kg and then they move together as a single body. The energy loss during the collision is

Option 1)

0.34\; J

 Option 2)

0.16\; J
Option 3)

1.00\; J

 Option 4)

0.67\; J
Read More

A person trying to lose weight by burning fat lifts a mass of 10 kg upto a height of 1 m 1000 times.  Assume that the potential energy lost each time he lowers the mass is dissipated.  How much fat will he use up considering the work done only when the weight is lifted up ?  Fat supplies 3.8×107 J of energy per kg which is converted to mechanical energy with a 20% efficiency rate.  Take g = 9.8 ms−2 :

Option 1)

2.45×10−3 kg

 Option 2)

 6.45×10−3 kg
Option 3)

 9.89×10−3 kg

 Option 4)

12.89×10−3 kg

 
Read More

An athlete in the olympic games covers a distance of 100 m in 10 s. His kinetic energy can be estimated to be in the range

Option 1)

2,000 \; J - 5,000\; J

 Option 2)

200 \, \, J - 500 \, \, J
Option 3)

2\times 10^{5}J-3\times 10^{5}J

 Option 4)

20,000 \, \, J - 50,000 \, \, J
Read More

A particle is projected at 600   to the horizontal with a kinetic energy K. The kinetic energy at the highest point

Option 1)

K/2\,

 Option 2)

\; K\;
Option 3)

zero\;

 Option 4)

K/4
Read More

In the reaction,

2Al_{(s)}+6HCL_{(aq)}\rightarrow 2Al^{3+}\, _{(aq)}+6Cl^{-}\, _{(aq)}+3H_{2(g)}

Option 1)

11.2\, L\, H_{2(g)}  at STP  is produced for every mole HCL_{(aq)}  consumed

 Option 2)

6L\, HCl_{(aq)}  is consumed for ever 3L\, H_{2(g)}      produced
Option 3)

33.6 L\, H_{2(g)} is produced regardless of temperature and pressure for every mole Al that reacts

 Option 4)

67.2\, L\, H_{2(g)} at STP is produced for every mole Al that reacts .
Read More

How many moles of magnesium phosphate, Mg_{3}(PO_{4})_{2} will contain 0.25 mole of oxygen atoms?

Option 1)

0.02

 Option 2)

3.125 × 10-2
Option 3)

1.25 × 10-2

 Option 4)

2.5 × 10-2
Read More

If we consider that 1/6, in place of 1/12, mass of carbon atom is taken to be the relative atomic mass unit, the mass of one mole of a substance will

Option 1)

decrease twice

 Option 2)

increase two fold
Option 3)

remain unchanged

 Option 4)

be a function of the molecular mass of the substance.
Read More

With increase of temperature, which of these changes?

Option 1)

Molality

 Option 2)

Weight fraction of solute
Option 3)

Fraction of solute present in water

 Option 4)

Mole fraction.
Read More

Number of atoms in 558.5 gram Fe (at. wt.of Fe = 55.85 g mol-1) is

Option 1)

twice that in 60 g carbon

 Option 2)

6.023 × 1022
Option 3)

half that in 8 g He

 Option 4)

558.5 × 6.023 × 1023
Read More

A pulley of radius 2 m is rotated about its axis by a force F = (20t - 5t2) newton (where t is measured in seconds) applied tangentially. If the moment of inertia of the pulley about its axis of rotation is 10 kg m2 , the number of rotations made by the pulley before its direction of motion if reversed, is

Option 1)

less than 3

 Option 2)

more than 3 but less than 6
Option 3)

more than 6 but less than 9

 Option 4)

more than 9
Read More

Colleges After 12th

Popular Course After 12th

Study Resources, Applications and Opportunities

ALLEN Coaching
ALLEN Coaching
Apply

Register for ALLEN Scholarship Test & get up to 90% Scholarship

NEET/JEE Coaching Scholarship
NEET/JEE Coaching Scholarship
Apply

Get up to 90% Scholarship on Offline NEET/JEE coaching from top Institutes

NEET Most scoring concepts
NEET Most scoring concepts
Get now

This ebook serves as a valuable study guide for NEET 2025 exam.

NEET Previous 10 Year Questions
NEET Previous 10 Year Questions
Get now

This e-book offers NEET PYQ and serves as an indispensable NEET study material.

JEE Main Important Physics formulas
Get now

As per latest 2024 syllabus. Physics formulas, equations, & laws of class 11 & 12th chapters

JEE Main Important Chemistry formulas
Get now

As per latest 2024 syllabus. Chemistry formulas, equations, & laws of class 11 & 12th chapters

View All Application Forms
News and Notifications
West Bengal Governor grants sanction to ED for prosecution of ex-Education Minister Partha Chatterjee
ACB files case against Sisodia, Jain for alleged corruption in classroom construction, AAP slams it as politic
Delhi School Fee Hike: How govt plans to check private schools with new bill and why it’s ‘complicated’
Three madrasa teachers held for assaulting minor students in Gujarat
Schools premises in Delhi identified for use during air exercise: Official communication
Delhi Cabinet approves bill to regulate fee in private, government schools
Arunachal Pradesh Guv bats for policy for children with special needs
Back to top