Science 7 · Unit 5: Properties of materials · Cambridge Lower Secondary Science Stage 7

Questions

1. 1. What is an alloy?

   • a mixture of a metal with other elements
   • a pure metal
   • a compound of two non-metals
   • a metal that is magnetic
   Check

2. 2. Which of these is an alloy?

   • gold
   • steel
   • copper
   • iron
   Check

3. 3. Which list contains only alloys?

   • iron, copper and tin
   • gold, silver and brass
   • steel, brass and bronze
   • steel, iron and zinc
   Check

4. 4. Which metals are mixed to make brass?

   • iron and carbon
   • copper and tin
   • gold and silver
   • copper and zinc
   Check

5. 5. Which elements are mixed to make bronze?

   • copper and zinc
   • iron and carbon
   • tin and lead
   • copper and tin
   Check

6. 6. Which element is added to iron to make steel?

   • zinc
   • oxygen
   • carbon
   • copper
   Check

7. 7. Why is pure iron not very useful for building?

   • It is too soft and bends easily.
   • It does not conduct electricity.
   • It is too brittle.
   • It is too shiny.
   Check

8. 8. Use particle theory. Why is steel stronger than pure iron?

   • The carbon atoms stop the layers of iron atoms sliding easily.
   • The carbon atoms make the iron atoms bigger.
   • Carbon makes iron a liquid.
   • The iron atoms are removed.
   Check

9. 9. How do the properties of an alloy compare with those of the metals it is made from?

   • They are different, often harder and stronger.
   • Alloys are never shiny.
   • They are always softer.
   • They are exactly the same.
   Check

10. 10. Stainless steel is used for cutlery and sinks. Which property makes it suitable?

    • It is magnetic.
    • It does not rust.
    • It is brittle.
    • It is very soft.
    Check

11. 11. You research an alloy. Which of these would be a reliable source?

    • an advert for jewellery
    • a random social media post
    • a science textbook or a university website
    • a guess from a friend
    Check

12. 12. Coins that look silver are not made of silver. What are they made of?

    • alloys containing copper and nickel
    • pure silver
    • plastic painted silver
    • pure iron
    Check

13. 13. Why is most gold jewellery, such as a wedding ring, not made of pure gold?

    • Pure gold is magnetic.
    • Pure gold rusts quickly.
    • Pure gold is not shiny.
    • Pure gold is soft, so it would wear away.
    Check

14. 14. Pure gold is 24 carat. How many parts out of 24 are pure gold in 18 carat gold?

    • 6
    • 24
    • 18
    • 12
    Check

15. 15. Planes are made mainly of aluminium. Which metals are added to make the stronger alloy duralumin?

    • iron and carbon
    • magnesium and copper
    • copper and tin
    • gold and silver
    Check