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?

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

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

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.

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.

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

State two ways to prevent the rusting of iron.

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

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

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

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.

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.

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.

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

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

What are alloys?

Which metals do not corrode easily?

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

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

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

Why do ionic compounds have high melting points?

Show the formation of Na₂O and MgO by the transfer of electrons.

Write the electron-dot structures for sodium, oxygen and magnesium.

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

Which gas is produced when dilute hydrochloric acid is added to a reactive metal? Write the chemical reaction when iron reacts with dilute H₂SO₄.

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

Why is sodium kept immersed in kerosene oil?

Explain the meanings of malleable and ductile

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.