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5411test- sources,


Sample Paper – 2009
Class – X
Subject – Science
 


Q-1 TO Q-10 CARRIES 1 MARK EACH,Q-11 TO Q -17 CARRIES 2 MARK EACH,Q-18 TO Q-24 CARRIES 3 MARK EACH



  1. Why should magnesium ribbon be cleaned before burning in air?
  2. Why does the colour of copper sulphate solution change when an iron nail is dipped into it?
  3. Why is respiration considered as exothermic reaction explain?
  4. What is a skeletal chemical equation?
  5. Why does calcium donot occur in free state in nature?
  6. Name two non metals which are both brittle and non ductile?
  7. Why utensils made of aluminum do not corrode?
  8. Why is iron more useful when it is mixed with a little carbon?
  9. How one can increase the efficiency of conventional resource of energy?
  10. What are semi conductors?
  11. What is an alloy? Give composition of brass, solder.
  12. Why is CNG better fossil fuel then crude oil of coal?
  13. What is global warming? How it effect the existence of human population?
  14. What are advantages and diosadvantages of nuclear power plant?
  15. What is a balanced chemical equation? What is need to balance an equation?
  16. What are redox reactions? Explain with the help of two examples?
  17. Define  mineral, ore, gangue.
  18. How can we harness energy from oceans?
  19. Explain how biogas is formed?
  20. Draw a line diagram showing the various processes in the extraction of a metal?
  21. How can copper be extracted by electrolytic refining?
  22. Give reasons for following


  1. Metals are electropositive
  2. Nitrogen gas is used to preserve food
  3. Silver does not displace hydrogen from dilute HCl.


  1. What happens when


  1. Calcium reacts with water
  2. Iron reacts with steam
  3. Magnesium reacts with hot water
  4. Sodium reacts with water


  1. Explain the following reactions with examples


  1. Precipitation reactions
  2. Double decomposition reaction
  3. Photography reaction

 



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