Chapter 4 Solutions — The World of Metals and Non-metals

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1. 1.
   Which metal is commonly used to make food packaging materials as it is cheaper, and its thin sheets can be folded easily into any shape?

   • (i) Aluminium
   • (ii) Copper
   • (iii) Iron
   • (iv) Gold
2. 2.
   Which of the following metal catches fire when it comes in contact with water?

   • (i) Copper
   • (ii) Aluminium
   • (iii) Zinc
   • (iv) Sodium
3. 3.
   State with reason(s) whether the following statements are True [T] or False [F].

   • (i) Aluminium and copper are examples of non-metals used for making utensils and statues.
   • (ii) Metals form oxides when combined with oxygen, the solution of which turns blue litmus paper to red.
   • (iii) Oxygen is a non-metal essential for respiration.
   • (iv) Copper vessels are used for boiling water because they are…
4. 4.
   Why are only a few metals suitable for making jewellery?
5. 5.
   Match the uses of metals and non-metals given in Column I with the jumbled names of metals and non-metals given in Column II. Column I:

   • (i) Used in electrical wiring
   • (ii) Most malleable and ductile
   • (iii) Living organisms cannot survive without it.
   • (iv) Plants grow healthy when fertilisers containing it are added to the soil.
   • (v) Used in water purification Column II:
   • (a) E N X Y G O
   • (b) N E C O H…
6. 6.
   What happens when oxygen reacts with magnesium and sulfur. What are the main differences in the nature of products formed?
7. 7.
   Complete the following flow chart: [A substance] + Air → Heat → Ash → Water → Add blue and red litmus solutions separately → Change in blue litmus solution: [?] → Change in red litmus solution: Blue → [Nature: ?]
8. 8.
   You are provided with the following materials. Discuss which material would be your choice to make a pan that is most suitable for boiling water and why? iron, copper, sulfur, coal, plastic, wood, cardboard
9. 9.
   You are provided with three iron nails, each dipped in oil, water and vinegar. Which iron nail will not rust, and why?
10. 10.
    How do the different properties of metals and non-metals determine their uses in everyday life?
11. 11.
    One of the methods of protecting iron from getting rusted is to put a thin coating of zinc metal over it. Since sulfur does not react with water, can it be used for this purpose? Justify your answer.
12. 12.
    An ironsmith heats iron before making tools. Why is heating necessary in this process?