Test paper of chapters The World of Metals and Non-metals & Changes Around Us: Physical and Chemical

 

1. Why are cooking utensils usually made of metals and not non-metals?

2. If you hit a metal and a non-metal with a hammer, how will they behave differently? Why?

3. Electrical wires are made of copper or aluminium. Why can’t we use sulfur or carbon instead?

4. Why do silver and gold jewellery remain shiny for a long time, while iron objects rust?

5.Why does charcoal (carbon) not react with water or acid easily, whereas zinc reacts with acid and releases gas?

6. When a metal is burnt in air, it forms a metal oxide. Why does this oxide turn red litmus blue when mixed with water?

7. If both oxygen and sulfur are non-metals, why does oxygen support burning but sulfur does not?

8. Why is sodium always stored in kerosene and not in water or air?

9. Non metals are generally bad conductors of electricity. Which non-metal is good conductor and why it is ? Explain.

10. Why are steel bridges painted regularly even though steel is stronger than wood?