Science 9 · Unit 5: Reactivity · Cambridge Lower Secondary Science Stage 9

Questions

1. 1. A metal displaces iron from iron sulfate and copper from copper sulfate, but not magnesium from magnesium sulfate. What does this tell you?

   • It is less reactive than copper.
   • It is more reactive than iron and copper, but less reactive than magnesium.
   • It is more reactive than magnesium.
   • It is exactly as reactive as iron.
   Check

2. 2. The unknown metal could be one of two metals. Which two?

   • silver or gold
   • sodium or potassium
   • lead or copper
   • aluminium or zinc
   Check

3. 3. How could you tell whether the unknown metal is aluminium or zinc?

   • Add it to zinc sulfate. Only aluminium would displace the zinc.
   • Add it to iron sulfate.
   • Add it to copper sulfate.
   • Add it to magnesium sulfate.
   Check

4. 4. Why can carbon be used to extract lead from lead oxide?

   • Carbon is more reactive than lead.
   • Carbon is a metal.
   • Lead is more reactive than carbon.
   • Lead oxide is not a compound.
   Check

5. 5. What is the word equation for heating lead oxide with carbon?

   • lead oxide + carbon → lead carbonate
   • lead + carbon dioxide → lead oxide + carbon
   • lead oxide + carbon → no reaction
   • lead oxide + carbon → lead + carbon dioxide
   Check

6. 6. Copper is less reactive than lead. Can carbon be used to extract copper from copper oxide?

   • Yes
   • No
   Check

7. 7. Why can't aluminium be extracted from aluminium oxide using carbon?

   • Aluminium oxide is too soft.
   • Carbon is more reactive than aluminium.
   • Aluminium is not a metal.
   • Aluminium is more reactive than carbon.
   Check

8. 8. Rails are welded using the thermite reaction. Which metal displaces iron from iron oxide?

   • silver
   • lead
   • aluminium
   • copper
   Check

9. 9. Why is the thermite reaction used to weld rails, rather than ordinary welding?

   • It is cold and safe.
   • It removes the rails.
   • It makes the rails out of aluminium.
   • It makes molten iron on the spot, without needing electricity.
   Check

10. 10. What is the word equation for the thermite reaction?

    • iron + aluminium oxide → iron oxide + aluminium
    • aluminium oxide + iron → aluminium + iron oxide
    • aluminium + iron oxide → no reaction
    • aluminium + iron oxide → aluminium oxide + iron
    Check

11. 11. In a blast furnace, which element displaces iron from iron oxide?

    • oxygen
    • aluminium
    • copper
    • carbon
    Check

12. 12. How is iron produced from iron oxide in a blast furnace?

    • Iron ore and coke (carbon) are heated together, and the carbon takes the oxygen from the iron oxide.
    • Iron oxide is dissolved in water and the iron sinks.
    • Iron oxide is cooled until the iron separates out.
    • Aluminium powder is added to iron oxide and lit.
    Check

13. 13. What is the word equation for the reaction in a blast furnace?

    • iron oxide + oxygen → iron + carbon
    • iron oxide → iron + oxygen
    • iron + carbon dioxide → iron oxide + carbon
    • iron oxide + carbon → iron + carbon dioxide
    Check

14. 14. Carbon can displace iron from iron oxide. Where does carbon fit in the reactivity series?

    • above iron
    • below iron
    • below copper
    Check

15. 15. Which of these metals can carbon displace from its oxide?

    • aluminium
    • iron
    • magnesium
    • potassium
    Check