Questions: Metals and Non Metals

Concepts of Metals  and Non Metals

In text Questions page number 40

Question 1. Give an example of a metal which (i) is a liquid at room temperature. (ii) can be easily cut with a knife. (iii) is the best conductor of heat. (iv) is a poor conductor of heat.

Question 2. Explain the meanings of malleable and ductile.

In text Questions page number 46

Question 1. Why is sodium kept immersed in kerosene oil?

Question 2. Write equations for the reactions of (i) iron with steam (ii) calcium and potassium with water

Question 3. Samples of four metals A, B, C and D were taken and added to the following solution one by one. The results obtained have been tabulated as follows.

Question 4. Which gas is produced when dilute hydrochloric acid is added to a reactive metal? Write the chemical reaction when iron reacts with dilute sulphuric acid.

Question 5. What would you observe when zinc is added to a solution of iron(II) sulphate? Write the chemical reaction that takes place.

In text Questions page number 49

Question 1.(i) Write the electron-dot structures for sodium, oxygen and magnesium. (ii) Show the formation of Na2O and MgO by the transfer of electrons. (iii) What are the ions present in these compounds?

Question 2. Why do ionic compounds have high melting points?

In text Questions page number 53

Question 1. Define the following terms. (i) Mineral (ii) Ore (iii) Gangue

Question 2. Name two metals which are found in nature in the free state.

Question 3. What chemical process is used for obtaining a metal from its oxide?

In text Questions page number 55

Quesiton 1. Metallic oxides of zinc, magnesium and copper were heated with the following metals.

Question 2. Which metals do not corrode easily?

Question 3. What are alloys?

Text Book Exercise

Question 1. Which of the following pairs will give displacement reactions? (a) NaCl solution and copper metal (b) MgCl2 solution and aluminium metal (c) FeSO4 solution and silver metal (d) AgNO3 solution and copper metal.

Question 2. Which of the following methods is suitable for preventing an iron frying pan from rusting? (a) Applying grease (b) Applying paint (c) Applying a coating of zinc (d) All of the above.

Question 3. An element reacts with oxygen to give a compound with a high melting point. This compound is also soluble in water. The element is likely to be (a) calcium (b) carbon (c) silicon (d) iron.

Question 4. Food cans are coated with tin and not with zinc because (a) zinc is costlier than tin. (b) zinc has a higher melting point than tin. (c) zinc is more reactive than tin. (d) zinc is less reactive than tin.

Question 5. You are given a hammer, a battery, a bulb, wires and a switch (a) How could you use them to distinguish between samples of metals and Non-metals? (b) Assess the usefulness of these tests in distinguishing between metals and non-metals.

Question 6. What are amphoteric oxides? Give two examples of amphoteric oxides.

Question 7. Name two metals which will displace hydrogen from dilute acids, and two metals which will not.

Question 8. In the electrolytic refining of a metal M, what would you take as the anode, the cathode and the electrolyte?

Question 9. Pratyush took sulphur powder on a spatula and heated it. He collected the gas evolved by inverting a test tube over it, as shown in figure below. (a) What will be the action of gas on (i) dry litmus paper? (ii) moist litmus paper? (b) Write a balanced chemical equation for the reaction taking place.

Question 10. State two ways to prevent the rusting of iron.

Question 11. What type of oxides are formed when non-metals combine with oxygen?

Question 12. Give reasons (a) Platinum, gold and silver are used to make jewellery. (b) Sodium, potassium and lithium are stored under oil. (c) Aluminium is a highly reactive metal, yet it is used to make utensils for cooking. (d) Carbonate and sulphide ores are usually converted into oxides during the process of extraction.

Question 13. You must have seen tarnished copper vessels being cleaned with lemon or tamarind juice. Explain why these sour substances are effective in cleaning the vessels.

Question 14. Differentiate between metal and non-metal on the basis of their chemical properties.

Question 15. A man went door to door posing as a goldsmith. He promised to bring back the glitter of old and dull gold ornaments. An unsuspecting lady gave a set of gold bangles to him which he dipped in a particular solution. The bangles sparkled like new but their weight was reduced drastically. The lady was upset but after a futile argument the man beat a hasty retreat. Can you play the detective to find out the nature of the solution he had used?

Quesiton 16. Give reasons why copper is used to make hot water tanks and not steel (an alloy of iron)