Question

(a) Name an alloy of copper. State its chemical composition and anyone use.
(b) Name five methods of preventing rusting of iron.
(c) What are the constituents of stainless steel? What are the special properties of stainless steel?

Answer 1

(a) An alloy of copper is bronze. The constituent elements of bronze are copper and tin. The composition of bronze is 90 per cent copper and 10 per cent tin. This alloy of copper is very strong and prevents corrosion. Bronze is used in the manufacturing of statues, medals, cooking vessels etc.

(b) Five methods of preventing rusting of iron are:

• By polishing the surface of iron with paint
• By applying oil or grease on the surface of the iron
• By coating a thin layer of zinc on the iron metal by the process called galvanisation
• By coating other metals like tin coating and chromium coating
• By alloying with other metals (chromium and nickel) to form stainless steel, which does not corrode

(c) The constituent elements present in stainless steel are iron, nickel and chromium.
Special properties of stainless steel are:

• It is hard and strong.
• It does not corrode (does not rust).

These properties make it suitable for making utensils for cooking.