Alloys and their uses sheet4-mark answer frameWhat are alloys? Why are they made? Give the composition and uses of any three alloys.
How to lay out the answer. Follow the frame, then write it in your own words.
- 1 · Define in one line. An alloy is a homogeneous mixture of two or more metals, or of a metal and a non-metal.
- 2 · Reasons for alloying.
- To increase hardness and strength
- To resist corrosion
- To lower the melting point
- To change the colour or appearance
- 3 · Three alloys.
- Brass: copper + zinc; electrical fittings, medals
- Bronze: copper + tin; statues, coins, bells
- Stainless steel: iron + carbon + nickel + chromium; utensils, surgical instruments
- 4 · Real-life link. Chola bronze statues, brass kuthuvilakku lamps and stainless steel tumblers are all alloys we see every day.
- 5 · Close in one line. Thus alloys give metals properties that the pure metals do not have.
Scoring tip: Write the metals in each alloy with chemical symbols too (Cu, Zn). Give two uses for each alloy.
