Physical and Chemical Changes Class 7 MCQs Questions with Answers
I. Choose the correct option.
Question 1.
Which of the following statement is incorrect for a chemical reaction?
(a) Heat may be given out but never absorbed
(b) Sound may be produced
(c) A colour change may take place
(d) A gas may be evolved
Answer
Answer: (a) Heat may be given out but never absorbed
Question 2.
Properties like size, shape, colour, state of a substance are
(a) chemical properties
(b) mental properties
(c) physical properties
(d) physico-chemical properties
Answer
Answer: (c) physical properties
Question 3.
A physical change is generally
(a) reversible
(b) irreversible
(c) considerable
(d) all of these
Answer
Answer: (a) reversible
Question 4.
During a physical change, a substance undergoes a change in its
(a) physical properties
(b) chemical properties
(c) both (a) and (b)
(d) none of these
Answer
Answer: (a) physical properties
Question 5.
Rusting of iron is a
(a) physical change
(b) chemical change
(c) both (a) and (b)
(d) all of these
Answer
Answer: (b) chemical change
Question 6.
Rusting occurs when iron is exposed to
(a) oxygen and water
(b) soil and rain
(c) breeze and sunlight
(d) salt water and clouds
Answer
Answer: (a) oxygen and water
Question 7.
When carbon dioxide is passed through lime water, the substance formed is
(a) calcium oxide
(b) calcium carbonate
(c) both (a) and (b)
(d) none of these
Answer
Answer: (b) calcium carbonate
Question 8.
A chemical change is also called a
(a) chemical reaction
(b) rusting
(c) both (a) and (b)
(d) all of these
Answer
Answer: (a) chemical reaction
Question 9.
Burning of any substance is a/an
(a) physical change
(b) chemical change
(c) irreversible change
(d) both (b) and (c)
Answer
Answer: (d) both (b) and (c)
Question 10.
The process of depositing a layer of zinc over iron is known as
(a) aluminisation
(b) galvanisation
(c) fertilisation
(d) ironing
Answer
Answer: (b) galvanisation
Question 11.
Two drops of dilute sulphuric acid were added to 1 g of copper sulphate powder and then 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
(a) physical and chemical changes respectively.
(b) chemical and physical changes respectively.
(c) both physical change
(d) both chemical change
Answer
Answer: (c) both physical change
Question 12.
Which among the following is a physical change?
(a) Burning of wood
(b) Ripening of fruit
(c) Cutting a log of wood in small pieces
(d) Cooking of food
Answer
Answer: (c) Cutting a log of wood in small pieces
Question 13.
Which of the following is a chemical change?
(a) Germination of seeds
(b) Cutting a piece of paper
(c) Bursting of fire crackers
(d) Both (a) and (c)
Answer
Answer: (d) Both (a) and (c)
Question 14.
A chemical change may bring
(a) evolution of gas
(b) change in colour
(c) change in taste
(d) all of these
Answer
Answer: (d) all of these
Question 15.
Which is the formula of ozone?
(a) Fe2O3
(b) Fe3O2
(c) O2
(d) O3
Answer
Answer: (d) O3
II. Fill in the Blanks
Question 1.
Setting curd from milk is a _________ change.
Answer
Answer: chemical
Question 2.
Broadly, changes are of two types, ________ and ________ .
Answer
Answer: physical, chemical
Question 3.
Physical properties of a substance consists of_________ , _______ , _______ and state.
Answer
Answer: shape, size, colour
Question 4.
No new substance is formed in a _________ change.
Answer
Answer: physical
Question 5.
Calcium carbonate is decomposed to form _________ and _________
Answer
Answer: calcium oxide, carbon dioxide
Question 6.
Magnesium on burning produces ________ .
Answer
Answer: magnesium oxide
Question 7.
Magnesium hydroxide is produced by mixing ________ with ________
Answer
Answer: magnesium oxide, water
Question 8.
_________ is a chemical change.
Answer
Answer: Burning
Question 9.
For rusting, the presence of both _________ and _________ is important.
Answer
Answer: oxygen, water(or moisture)
Question 10.
Rusting can be prevented by , _________ , _______ and _________ the iron articles.
Answer
Answer: polishing, painting, oiling
Question 11.
A physical change is generally _________ .
Answer
Answer: reversible
Question 12.
Making sugar solution is a _________ change.
Answer
Answer: physical
Question 13.
The formula of sodium hydrogen carbonate is _________ .
Answer
Answer: NaHCO3
Question 14.
Burning of candle shows both ________ and ________ changes.
Answer
Answer: physical, chemical
Question 15.
Large crystals of pure substances are obtained by __________ .
Answer
Answer: crystallisation
III. True or False
Question 1.
Stainless steel is made by mixing aluminium with carbon.
Answer
Answer: False
Question 2.
Burning of any substance is a chemical change.
Answer
Answer: True
Question 3.
Stretching of rubber band is a physical change.
Answer
Answer: True
Question 4.
We must use concentrated sulphuric acid for crystallisation of copper sulphate.
Answer
Answer: False
Question 5.
Changes are broadly classified as physical and chemical changes.
Answer
Answer: True
Question 6.
Galvanizing is a physical change.
Answer
Answer: True
Question 7.
Rusting is a chemical change.
Answer
Answer: True
Question 8.
The symbol of rust is Fe2O3.
Answer
Answer: True
Question 9.
A chemical change is also called a chemical reaction.
Answer
Answer: True
Question 10.
In chemical changes, new substances are produced.
Answer
Answer: True
Question 11.
The process of photosynthesis is a chemical change.
Answer
Answer: True
Question 12.
Cooking of rice is a physical change.
Answer
Answer: False
Question 13.
Burning of cracker is a physical change.
Answer
Answer: False
Question 14.
The mass of a substance changes during a chemical change.
Answer
Answer: True
Question 15.
Chemical change is permanent.
Answer
Answer: True
IV. Match the Following
| Column I | Column II |
| 1. Physical change | (a) Irreversible |
| 2. Chemical change | (b) CaO + CO2 |
| 3. Burning | (c) Chemical change |
| 4. MgO + H2O | (d) Ferric oxide |
| 5. CaCO3 | (e) Mg(OH)2 |
| 6. Chemical formula of rust | (f) Do not corrode |
| 7. Galvanisation | (g) Reversible |
| 8. Baking soda | (h) Sodium hydrogen carbonate |
| 9. Stainless steel | (i) Process of formation of crystals |
| 10. Crystallisation | (j) Zinc coating on iron |
Answer
Answer:
| Column I | Column II |
| 1. Physical change | (g) Reversible |
| 2. Chemical change | (a) Irreversible |
| 3. Burning | (c) Chemical change |
| 4. MgO + H2O | (e) Mg(OH)2 |
| 5. CaCO3 | (b) CaO + CO2 |
| 6. Chemical formula of rust | (d) Ferric oxide |
| 7. Galvanisation | (j) Zinc coating on iron |
| 8. Baking soda | (h) Sodium hydrogen carbonate |
| 9. Stainless steel | (f) Do not corrode |
| 10. Crystallisation | (i) Process of formation of crystals |
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