CBSE  /  Class 7  /  Science  /  Physical and Chemical Changes

  • 1. 
    In which type of change a new substance is formed?

  • In physical change
  • In chemical change
  • In both (a) and (b)
  • In neither of these

  • 2. 
    Which among the following is a physical change?

  • Cutting a log of wood in small pieces
  • Burning of wood
  • Ripening of fruit
  • Cooking of food

  • 3. 
    Which of the following is a chemical change?

  • Bursting of a fire cracker
  • Germination of seed
  • Coal formation from buried trees
  • All of these

  • 4. 
    Which is a method to prevent rust?

  • Crystallization
  • Sedimentation
  • Galvanisation
  • None of these

  • 5. 
    How crystal of pure substances are obtained?

  • By crystallization
  • By chromatography
  • By peptization
  • By all these methods

  • 6. 
    What is the formula of rust?

  • Fe
  • Fe
  • FeO
  • None of these

  • 7. 
    What will happen if carbon dioxide gas is passed through lime water ?

  • Calcium carbonate is formed
  • The lime water turns milky
  • Both of these
  • None of these

  • 8. 
    Iron pillar near the Qutub Minar in Delhi is famous for the following facts. Which of these facts is responsible for its long stability?

  • It is more than 7 metres high
  • It weighs about 6000 kg
  • It was built more than 1600 years ago
  • It has not rusted after such a long period

  • 9. 
    Galvanisation is a process used to prevent the rusting of which of the following?

  • Iron
  • Zinc
  • Aluminium
  • Copper

  • 10. 
    Paheli’s mother made a concentrated sugar syrup by dissolving sugar in hot water. On cooling, crystals of sugar got separated. This indicates a:

  • physical change that can be reversed
  • chemical change that can be reversed
  • physical change that cannot be reversed
  • chemical change that cannot be reversed
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