CBSE Class 7 Science - MCQ and Online Tests - Unit 6 - Physical and Chemical Change

CBSE Class 7 Science – MCQ and Online Tests – Unit 6 – Physical and Chemical Change

 

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CBSE Class 7 Science – MCQ and Online Tests – Unit 6 – Physical and Chemical Change

Choose the correct answer:

Question 1.
What is the formula of rust?
(a) Fe₂O₃
(b) Fe₃O₄
(c) FeO
(d) None of these

Answer

Answer: (a) Fe₂O₃

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Question 2.
Galvanisation is a process used to prevent the rusting of which of the following?
(a) Iron
(b) Zinc
(c) Aluminium
(d) Copper

Answer

Answer: (a) Iron

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Question 3.
Which among the following is a physical change?
(a) Cutting a log of wood in small pieces
(b) Burning of wood
(c) Ripening of fruit
(d) Cooking of food

Answer

Answer: (a) Cutting a log of wood in small pieces

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Question 4.
Which of the following is a chemical change?
(a) Bursting of a fire cracker
(b) Germination of seed
(c) Coal formation from buried trees
(d) All of these

Answer

Answer: (d) All of these

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Question 5.
Which is a method to prevent rust?
(a) Crystallization
(b) Sedimentation
(c) Galvanisation
(d) None of these

Answer

Answer: (c) Galvanisation

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Question 6.
In which type of change a new substance is formed?
(a) In physical change
(b) In chemical change
(c) In both (a) and (b)
(d) In neither of these

Answer

Answer: (b) In chemical change

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Question 7.
How crystal of pure substances are obtained?
(a) By crystallization
(b) By chromatography
(c) By peptization
(d) By all these methods

Answer

Answer: (a) By crystallization

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Question 8.
Paheli’s mother made a concentrated sugar syrup by dissolving sugar in hot water. On cooling, crystals of sugar got separated. This indicates a:
(a) physical change that can be reversed
(b) chemical change that can be reversed
(c) physical change that cannot be reversed
(d) chemical change that cannot be reversed

Answer

Answer: (a) physical change that can be reversed

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Question 9.
What will happen if carbon dioxide gas is passed through lime water ?
(a) Calcium carbonate is formed
(b) The lime water turns milky
(c) Both of these
(d) None of these

Answer

Answer: (c) Both of these

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Question 10.
Iron pillar near the Qutub Minar in Delhi is famous for the following facts. Which of these facts is responsible for its long stability?
(a) It is more than 7 metres high
(b) It weighs about 6000 kg
(c) It was built more than 1600 years ago
(d) It has not rusted after such a long period

Answer

Answer: (d) It has not rusted after such a long period

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