Metals, Non-metals, Alloys and Metallurgy

Attempt the quiz above first, then review every question with its correct answer and a short explanation below.

1. Q1.The most abundant metal in the Earth's crust is:

   • A.iron
   • B.copper
   • C.aluminium✓ Correct Answer
   • D.sodium

   Explanation: Aluminium makes up about 8 per cent of the crust.

2. Q2.The only metal that is liquid at room temperature is:

   • A.lead
   • B.mercury✓ Correct Answer
   • C.tin
   • D.zinc

   Explanation: Mercury melts at about -39 °C.

3. Q3.The best conductor of electricity among metals is:

   • A.silver✓ Correct Answer
   • B.copper
   • C.gold
   • D.aluminium

   Explanation: Copper is the next best and is used for wires because it is cheaper.

4. Q4.The chief ore of aluminium is:

   • A.haematite
   • B.bauxite✓ Correct Answer
   • C.galena
   • D.cinnabar

   Explanation: Bauxite is hydrated aluminium oxide.

5. Q5.Haematite is an ore of:

   • A.aluminium
   • B.copper
   • C.lead
   • D.iron✓ Correct Answer

   Explanation: Its formula is Fe2O3.

6. Q6.Steel is an alloy of iron and:

   • A.copper
   • B.carbon✓ Correct Answer
   • C.zinc
   • D.tin

   Explanation: A small amount of carbon makes iron harder.

7. Q7.Bronze is an alloy of:

   • A.copper and zinc
   • B.copper and tin✓ Correct Answer
   • C.iron and nickel
   • D.lead and tin

   Explanation: Bronze is made by alloying copper with tin, and is harder than pure copper.

8. Q8.Rusting of iron requires:

   • A.both oxygen and water✓ Correct Answer
   • B.only dry air
   • C.only nitrogen
   • D.only carbon dioxide

   Explanation: Rust is hydrated iron(III) oxide.

9. Q9.Coating iron with a layer of zinc to prevent rusting is called:

   • A.anodising
   • B.galvanisation✓ Correct Answer
   • C.roasting
   • D.smelting

   Explanation: Zinc protects iron even where the coating is scratched.

10. Q10.Heating a sulphide ore strongly in excess air is called:

    • A.calcination
    • B.galvanisation
    • C.roasting✓ Correct Answer
    • D.electrolysis

    Explanation: The sulphide converts to the oxide, releasing sulphur dioxide.

11. Q11.Heating a carbonate ore in limited or no air is called:

    • A.roasting
    • B.smelting
    • C.refining
    • D.calcination✓ Correct Answer

    Explanation: It drives off carbon dioxide and moisture.

12. Q12.The thermite reaction uses aluminium to reduce:

    • A.sodium chloride
    • B.water
    • C.carbon dioxide
    • D.iron(III) oxide✓ Correct Answer

    Explanation: The reaction is so exothermic it yields molten iron for welding rails.

13. Q13.The hardest natural substance known is:

    • A.graphite
    • B.quartz
    • C.diamond✓ Correct Answer
    • D.steel

    Explanation: It is an allotrope of carbon.

14. Q14.The non-metal that conducts electricity is:

    • A.graphite✓ Correct Answer
    • B.diamond
    • C.sulphur
    • D.phosphorus

    Explanation: Graphite has free electrons between its layers.

15. Q15.Gold is considered a noble metal because it is:

    • A.very unreactive and does not corrode✓ Correct Answer
    • B.very light
    • C.highly reactive
    • D.magnetic

    Explanation: It resists attack by air and most acids.

16. Q16.An amalgam is an alloy containing:

    • A.lead
    • B.carbon
    • C.sodium
    • D.mercury✓ Correct Answer

    Explanation: Dental fillings used silver amalgam.

17. Q17.Aluminium is extracted from alumina commercially by:

    • A.reduction with carbon
    • B.roasting only
    • C.calcination only
    • D.electrolysis in molten cryolite✓ Correct Answer

    Explanation: The Hall-Heroult process uses cryolite to lower the melting point.

18. Q18.Aqua regia, which dissolves gold, is a mixture of:

    • A.concentrated hydrochloric acid and nitric acid in a 3:1 ratio✓ Correct Answer
    • B.sulphuric and acetic acid
    • C.nitric acid and water
    • D.hydrochloric acid and sodium hydroxide

    Explanation: Neither acid alone dissolves gold.

19. Q19.In a blast furnace for iron, limestone is added to act as a:

    • A.catalyst for carbon
    • B.reducing agent for iron
    • C.flux that removes silica as slag✓ Correct Answer
    • D.fuel

    Explanation: Calcium oxide combines with silica to form calcium silicate slag.

20. Q20.The reducing agent in the blast furnace is mainly:

    • A.oxygen
    • B.nitrogen
    • C.carbon monoxide✓ Correct Answer
    • D.limestone

    Explanation: Coke burns to form carbon monoxide, which reduces iron oxide.