Changes Around Us Book Back Questions

8th Standard EM

    Reg.No. :
  •  
  •  
  •  
  •  
  •  
  •  

Science

Time : 00:45:00 Hrs
Total Marks : 30
    4 x 1 = 4
  1. Burning of paper is a______ change.

    (a)

    Physical

    (b)

    chemical

    (c)

    physical & chemical

    (d)

    neutral

  2. ______ metal undergoes rusting.

    (a)

    tin

    (b)

    sodium

    (c)

    copper

    (d)

    iron

  3. Which of the following factor induces electrolysis?

    (a)

    Heat

    (b)

    light

    (c)

    electricity

    (d)

    catalysis

  4. Dissolved gases like sulphur dioxide, nitrogen oxides in rain water causes______

    (a)

    Acid rain

    (b)

    base rain

    (c)

    heavy rain

    (d)

    neutral rain

  5. 3 x 1 = 3
  6. ______ is the basic material to manufacture urea.

    ()

    Ammonia

  7. Electrolysis of Brine solution gives ______ gases.

    ()

    Chlorine and hydrogen

  8. ______ is the enzyme responsible for browning of vegetables, fruits.

    ()

    Polyphenol oxidase or tyrosinase.

  9. 3 x 1 = 3
  10. Formation of slaked lime from quicklime is a endothermic reaction.

    (a) True
    (b) False
  11. CFC is a pollutant.

    (a) True
    (b) False
  12. Browning of some vegetables and fruits is due to tannin formation.

    (a) True
    (b) False
  13. 3 x 2 = 6
  14. On heating, calcium carbonate gives calcium oxide and oxygen. Is it exothermic reaction or endothermic reaction?

  15. What is the role of a catalyst in a chemical reaction?

  16. Why photosynthesis is a chemical reaction?

  17. 3 x 3 = 9
  18. Discuss acid rain occurs due to emission of smoke from vehicles and industries?

  19. Is rusting good for Iron materials? Explain.

  20. Do all the fruits and vegetables undergo browning? Explain.

  21. 1 x 5 = 5
  22. Explain how food items are spoilt due to chemical reactions?

*****************************************

Reviews & Comments about 8th Standard Science - Changes Around Us Book Back Questions

Write your Comment