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

Questions

1. 1. Zara adds copper carbonate to hydrochloric acid. What happens?

   • It fizzes, as carbon dioxide is given off.
   • Nothing happens.
   • It gives a squeaky pop.
   • It turns into a solid.
   Check

2. 2. Why does Zara keep adding copper carbonate until there is no more reaction?

   • to colour the solution
   • to make the solution acidic
   • to make more carbon dioxide for later
   • to make sure all the acid has reacted
   Check

3. 3. Sofia filters the mixture. What is left in the filter paper?

   • the unreacted copper carbonate
   • copper chloride crystals
   • hydrochloric acid
   • nothing
   Check

4. 4. What is the filtrate?

   • copper chloride solution
   • copper carbonate
   • hydrochloric acid
   • pure water
   Check

5. 5. How do Sofia and Zara get crystals of copper chloride from the solution?

   • Heat it to evaporate some of the water, then leave it to crystallise.
   • Filter it again.
   • Cool it in a freezer straight away.
   • Add more acid.
   Check

6. 6. Why must they be careful when heating the solution?

   • The solution freezes.
   • The hot solution can spit.
   • The filter paper catches fire.
   • The crystals can explode.
   Check

7. 7. What is the word equation for copper carbonate and hydrochloric acid?

   • copper carbonate + hydrochloric acid → copper chloride + water + carbon dioxide
   • copper carbonate + hydrochloric acid → copper + water + carbon dioxide
   • copper carbonate + hydrochloric acid → copper sulfate + water
   • copper carbonate + hydrochloric acid → copper chloride + hydrogen
   Check

8. 8. What is the general equation for an acid reacting with a carbonate?

   • acid + carbonate → oxide + water
   • acid + carbonate → salt + hydrogen
   • acid + carbonate → salt + water
   • acid + carbonate → salt + water + carbon dioxide
   Check

9. 9. To make potassium chloride from potassium hydroxide, which acid is needed?

   • sulfuric acid
   • citric acid
   • hydrochloric acid
   • nitric acid
   Check

10. 10. Which equipment adds the acid a little at a time to neutralise 20 cm³ of potassium hydroxide?

    • a beaker
    • a burette
    • a crucible
    • a test tube
    Check

11. 11. How do Zara and Marcus know when the potassium hydroxide has been neutralised?

    • It smells different.
    • The indicator changes to its neutral colour.
    • It starts to fizz.
    • It turns cloudy.
    Check

12. 12. How can they remove the indicator's colour so the potassium chloride crystals are pure?

    • Add more indicator.
    • Add more alkali.
    • Repeat with the same volumes but no indicator, or add charcoal and filter.
    • Boil it until the colour goes.
    Check

13. 13. What is the word equation for potassium hydroxide and hydrochloric acid?

    • potassium hydroxide + hydrochloric acid → potassium chloride + hydrogen
    • potassium hydroxide + hydrochloric acid → potassium chloride + water
    • potassium hydroxide + hydrochloric acid → potassium oxide + water
    • potassium + hydrochloric acid → potassium chloride + water
    Check

14. 14. What is the symbol equation for potassium hydroxide and hydrochloric acid?

    • KOH + HCl → KCl + H₂O
    • KOH + HCl → KCl + H₂
    • KOH + HCl → KH + ClOH
    • K + HCl → KCl + H₂
    Check

15. 📖 This question is about a text that students read in the app.

    15. Substance A gave a gas that turned limewater milky. Which gas?

    • oxygen
    • hydrogen
    • chlorine
    • carbon dioxide
    Check

16. 📖 This question is about a text that students read in the app.

    16. Substance C gave a gas that made a squeaky pop with a lighted splint. Which gas?

    • hydrogen
    • carbon dioxide
    • nitrogen
    • oxygen
    Check

17. 📖 This question is about a text that students read in the app.

    17. What is the general name for the crystalline substances made by evaporation?

    • oxides
    • acids
    • salts
    • alkalis
    Check

18. 📖 This question is about a text that students read in the app.

    18. Substance A fizzed, gave carbon dioxide and made zinc sulfate. What were A and the liquid?

    • zinc oxide and hydrochloric acid
    • zinc and sulfuric acid
    • zinc carbonate and hydrochloric acid
    • zinc carbonate and sulfuric acid
    Check

19. 📖 This question is about a text that students read in the app.

    19. Substance B made iron chloride with no bubbles. What were B and the liquid?

    • iron and hydrochloric acid
    • iron oxide and hydrochloric acid
    • iron carbonate and hydrochloric acid
    • iron oxide and sulfuric acid
    Check

20. 📖 This question is about a text that students read in the app.

    20. Substance C gave hydrogen and made magnesium chloride. What were C and the liquid?

    • magnesium and sulfuric acid
    • magnesium carbonate and hydrochloric acid
    • magnesium and hydrochloric acid
    • magnesium oxide and hydrochloric acid
    Check