Thursday, 25 February 2021

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


 

Every year CBSE students attend Annual Assessment exams for 6,7,8,9,11th standards. These exams are very competitive to all the students. So our website provides online tests for all the 6,7,8,9,11th standards’ subjects. These tests are also very effective and useful for those who preparing for any competitive exams like Olympiad etc. It can boost their preparation level and confidence level by attempting these chapter wise online tests.

These online tests are based on latest CBSE syllabus. While attempting these, our students can identify their weak lessons and continuously practice those lessons for attaining high marks. It also helps to revise the NCERT textbooks thoroughly

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


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


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


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


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

Answer

Answer: (c) Galvanisation


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


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


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


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


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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