TOPIC: PHYSICAL AND CHEMICAL CHANGES
ANSWER THE FOLLOWING
Q1. Classify the following changes into physical and chemical changes
(i) Galvanization of Iron
(ii) Explosion of crackers
(iii) Decaying of organic matter
(iv) Breaking of glass
(v) Formation of clouds
Q2. A slice of apple acquires a brown colour, if it is not consumed immediately. Why?
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Q3. Why is burning of magnesium ribbon in air a chemical change?
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Q4. What kind of change is shown by the tearing of paper? How is it different from burning of paper?
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Q5. Explain the following
(a) Lime water turns milky on passing carbon dioxide gas into it.
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(b) Bubbles are produced, when acetic acid is added to a solution of sodium bicarbonate.
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Q6. A student took a solution of copper sulphate in a beaker and put a clean iron nail into it and left it for about one hour.
(a) What change do you expect?
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(b) What type of change is this?
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(c) Write a word equation for the above reaction.
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Q7. Write whether magnetisation of steel is a physical change or not? How is it different from magnetisation of iron?
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Q8. How painting of an iron article prevents it from rusting?
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Please click on below link to download CBSE Class 7 Science Physical And Chemical Change Worksheet Set B