Science 8 · Unit 2: Properties of materials · Cambridge Lower Secondary Science Stage 8

Questions

1. 1. What is a solute?

   • the liquid that does the dissolving
   • the solid left in a filter
   • the substance that dissolves
   • the mixture formed
   Check

2. 2. What is a solvent?

   • the substance that dissolves
   • the mixture formed
   • the liquid that the solute dissolves in
   • a filter
   Check

3. 3. What is a solution?

   • the mixture formed when a solute dissolves in a solvent
   • a substance that will not dissolve
   • the solid left after filtering
   • a pure solid
   Check

4. 4. What is the difference between dissolving and melting?

   • They are the same thing.
   • Dissolving needs a solvent; melting is a solid turning to liquid by heating.
   • Melting needs a solvent.
   • Dissolving needs heat only.
   Check

5. 5. What is the difference between transparent and opaque?

   • Opaque lets more light through.
   • Transparent materials are always coloured.
   • They are the same.
   • Light passes through transparent materials but not opaque ones.
   Check

6. 6. 20 g of salt is dissolved in 100 g of water. What is the mass of the solution?

   • 100 g
   • 20 g
   • 120 g
   • 80 g
   Check

7. 7. Why does dissolved salt seem to disappear?

   • Its particles spread out between the water particles and are too small to see.
   • It is destroyed.
   • It evaporates immediately.
   • It turns into water.
   Check

8. 8. What is a filtrate?

   • the solid left in the filter
   • the filter paper
   • the solute
   • the liquid that passes through a filter
   Check

9. 9. Is a solution of salt in water transparent?

   • Yes
   • No
   Check

10. 10. Can a filter separate salt from a salt solution?

    • Only with paper towel.
    • Yes, the salt stays in the filter.
    • No, the dissolved particles pass through.
    • Yes, if you filter twice.
    Check

11. 11. Which is a mixture but not a solution?

    • salt in water
    • copper sulfate in water
    • sand in water
    • sugar in water
    Check

12. 12. What happens to the particles of a solute when it dissolves?

    • They vanish.
    • They separate and spread out among the solvent particles.
    • They float to the top.
    • They join into a bigger crystal.
    Check

13. 13. What do we call a substance that dissolves in a solvent?

    • saturated
    • opaque
    • insoluble
    • soluble
    Check

14. 14. Which law explains why the mass of a solution equals solute plus solvent?

    • conservation of mass
    • law of reflection
    • conservation of colour
    • law of gravity only
    Check

15. 15. Milk is opaque. Is milk a solution?

    • Yes, it is a liquid.
    • Yes, it has things dissolved in it.
    • No, all solutions are transparent.
    • No, solutions are always coloured.
    Check

16. 16. 9 g of salt is dissolved in 50 g of water. What is the mass of the salt solution?

    • 50 g
    • 41 g
    • 9 g
    • 59 g
    Check

17. 17. A green powder is stirred into water. The water looks cloudy and lumps of powder can still be seen. Has a solution formed?

    • Yes
    • No
    Check