Which of the Following Are Chemical Changes? - Science


Which of the following are chemical changes?

(a) Growth of a plant

(b) Rusting of iron

(c) Mixing of iron fillings and sand

(d) Cooking of food

(e) Digestion of food

(f) Freezing of water

(g) Burning of candle



The following changes are chemical changes:

(a) Growth of a plant

(b) Rusting of iron

(d) Cooking of food

(e) Digestion of food

(g) Burning of candle

  Is there an error in this question or solution?
Chapter 2: Is Matter around us Pure - Exercises [Page 30]


NCERT Science Class 9
Chapter 2 Is Matter around us Pure
Exercises | Q 11 | Page 30


Classify the following as chemical or physical changes: Melting of butter in a pan

Classify the following as chemical or physical changes:- Making a fruit salad with raw fruits

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


Dissolving sugar in water

Burning of coal

Melting of wax

Beating aluminium to make aluminium foil

Digestion of food

Fill in the blanks in the following statements:

Changes in which only _____ __ properties of a substance change are called physical changes.

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.

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

Photosynthesis cannot take place at night.

State the differences between a physical change and a chemical change.

Make a list of different types of changes with example.

Define physical change. Give two examples for the above changes.

A burning candle shows both physical and chemical changes. Explain ?

Name a chemical change which takes place in presence of:

Write true or false

Cutting of paper into pieces is a chemical change.

Write true or false 

Melting of ice is a physical change.

True or false 

Is melting of ice a reversible change?

Write true or false

Deforestation is a man-made change.

Two chemical substances X and Y combine together to form a product P which contains both X and Y X + Y 􀁯 P
X and Y cannot be broken down into simpler substances by simple chemical reactions. Which of the following  statements concerning X, Y and P are correct ?

  1. P is a compound
  2. X and Y are compounds
  3. X and Y are elements
  4. P has a fixed composition

Classify the following as physical or chemical change :

Growth of a plant

Classify the following as physical or chemical changes :

Breaking of a glass tumbler

Which of the following are physical changes and which are chemical changes?

Burning of candle wax, Melting of candle wax, Mixing of iron filings and sand, Burning of wood, Breaking a piece of chalk, Burning a piece of paper, Cutting a piece of paper.

What is a chemical change ? Give two examples of chemical changes.

Give the main differences between physical changes and chemical changes.

Which of the following are physical changes ?

  1. melting of iron metal
  2. rusting of iron metal
  3. bending of an iron rod
  4. drawing a wire of iron metal

Classify the following as a physical or a chemical change.

Butter getting rancid

Fill in the blank.

A change, which alters the composition of a substances, is known as a___________ change.

Distinguish between the following.

Physical change and chemical change

What will you take into account while identifying the following?

A physical change in a substance.

What will you take into account while identifying the following?

A chemical change in a substance.

Read the paragraph and note down the various types of changes it mentions.
It was nearing six o'clock in the evening. The sun was setting. A breeze was blowing. Leaves on the tree were shaking. Sahil was sitting in the courtyard, rolling balls of wet soil, and shaping them into various toys. Then he felt hungry and went into the house. Mother made a dough from wheat flour and fried purees. While eating hot purees, his attention was drawn outside the window. It had started raining. There was lightning, too. Sahil was enjoying his dinner in the dim light.

Change is the law of nature and occurs in our everyday life, at all times and in all places.
Differentiate between the following change with a suitable example.

Periodic and non-periodic change

Fill in the blanks with the appropriate words of the statement  given below:

Heating a piece of iron is considered a __________ change while heating a piece of coal [carbon] is considered a ___________ change.

Match the examples of changes in List I with the correct.

List I List II
1. Expansion of a steel rod on heating A: Physical change
2. Rotting of eggs B: Chemical change
3. Milk turning sour  
4. Tarnishing of copper  
5. Separation of naphthalene from a mixture of naphthalene and sodium chloride.  

Name the following:

The term involved in the change of state from – ‘water to ice’ – which is a physical change.

Name the following:

The final product of the physical change involved during the ‘melting of a piece of wax’.

State which of the following pertain to – chemical changes.

(a) Substance retains its identity
(b) The change is permanent
(c) No new substance is formed
(d) Is easily reversible
(e) Produces one or more new substances by a change in its composition
(f) The change is temporary
(g) The composition and properties of the original substance are not altered.

Select the chemical changes from the following list of changes

Vaporisation of water into water vapour.

Select the chemical changes from the following list of changes

Butter turning rancid

When ice melts to form water, change occurs in its

In a solution of salt in water, water is the solute

You are given some candle wax. Can you make a candle doll from it? What kind of change is this?

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

Wood to sawdust:______:: Wood to Ash: Chemical change

What type of change is colouring of a paper?

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

Higher order Thinking question

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

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.

Sublimation of Iodine is a ______.

______ is the substance that is dissolved in a solvent.

Gas exists in three states as solid, liquid, and gas.

When solute is dissolved in a solvent it forms a solution.

Natural changes which take place in nature on their own, are beyond the control of human being.


Melting of ice: Physical change.
Popping of popcorn: ______.

Water is known as a universal solvent. Why?

______ is the Universal Solvent.

Classify the following as physical or chemical properties

Metallic sodium is soft enough to be cut with a knife.

Paheli’s mother made a concentrated sugar syrup by dissolving sugar in hot water. On cooling, crystals of sugar got separated. This indicates a 

Two drops of dilute sulphuric acid were added to 1 g of copper sulphate powder and then a small amount of hot water was added to dissolve it (step I). On cooling, beautiful blue coloured crystals got separated (step II). Step I and Step II are:

State whether the following statements are true or false:

Anaerobic bacteria digest animal waste and produce biogas.

What kind of change is shown by tearing off paper?

Match the items of Column I with the items of Column II

Column 1 Column II
(a) Large crystals (i) Turns lime water into milky
(b) Depositing a layer of zinc on iron (ii) Physical change
(c) Souring of milk (iii) Rust
(d) Carbon dioxide (iv) Sugar candy (Mishri)
(e) Iron oxide (v) Chemical change
(f) Dissolving common salt in water (vi)  Galvanisation

Give two examples for each of the following cases:

Physical changes which are not reversible.

Which of the following is not a physical change?

Cutting a log of wood into pieces is a chemical change.

Adding sugar to milk is a physical change.

Mention a few physical properties of a substance.

Mention some of the different conditions needed for chemical changes to occur.


      Forgot password?
Use app×