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Friday, August 19, 2011

CBSE Guess Paper SCIENCE Class-10 Chapter 3. Metal and Non-metals

   CBSE Guess Paper SCIENCE Class-10 Chapter 3. Metal and Non-metals
Q.1. Why is sodium kept immersed in kerosene oil?
Q.2. Name two metals which are found in nature in the free state.
Q.3. What chemical process is used for obtaining a metal from its oxide.
Q.4. Which metals do not corrode easily?
Q.5. Why copper is used to make hot water tanks and not steel .
Q.6. What is an alloy? Name the constituents of 22-carat gold. Why is 24-carat gold converted to 22-carat gold?
Q.7. Why are metals good conductors of electricity?
Q.8 Give reasons for the following: (a) Zinc oxide is considered as amphoteric oxide. (b) Non-metals in general do not displace hydrogen from dilute acids. (c) Metals conduct electricity.
Q.9 Show that both air and water are necessary for corrosion of iron.
Q.10 Explain why: (i)iron sheets are coated with zinc. (ii)we apply paint on iron articles. (iii)the galvanized iron article is protected against rusting even if the zinc layer is broken.
Q.11 (i) What is an ‘activity series of metals’? Arrange themetals Zn, Mg, Al, Cu and Fe in a decreasing order of reactivity. (ii) What would you observe when you put (a) Some zinc pieces into blue copper sulhate solution?
(b) Some copper pieces into green ferrous sulphate solution? (c ) Name a metal which combines with hydrogen gas. Name the compound formed.
Q.12. State two ways to prevent the rusting of iron.
Q.13. What type of oxides are formed when non-metalscombine with oxygen?
Q.14. Name a metal which is both ductile as well as malleable.
Q,15. Write the chemical equation to represent the reaction taking place when copper oxide is heated in a stream of hydrogen.
Q.16. The reaction of a metal X with Fe2O3 is highlyexothermic and is used to join broken railway tracks. Identify metal X. Write the chemical equation of its reaction with Fe2O3.
Q.17 NIKITA took sulphur powder on a spatula and heated it. He collected the gas evolved by inverting a test-tube over it. .
i) What will be the action of gas an (a) dry litmus paper? (b) Moist litmus paper?
(ii) Write a balanced chemical equation for the reaction taking place.
Q.18 Why do ionic compounds have high melting points?
Q.19. Give reasons:(i) Platinum, gold and silver are used tomake jewellery.
Q.20 What is corrosion of metals? Name one metal which does not corrode and one which corrodes on being kept in atmosphere.

2 comments:

Jsunil said...

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Umaima Shaikh said...

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