Saturated, unsaturated and supersaturated solutions

Answer Key - Grade 10 Science Worksheet

Circle the best answer, or write your answer on the line.

1. 1.

   Sugar dissolves up to 200 g per 100 mL of water at 25 °C. What is the most that dissolves in 75 mL of water at 25 °C, Jun?

   150 g
2. 2.

   Baking soda's limit is 12.7 g per 100 g of water at 40 °C. A solution at 40 °C holds 10.0 g per 100 g. Which is it, Kira?

   • Saturated
   • Supersaturated
   • Unsaturated
3. 3.

   Baking soda's limit is 9.6 g per 100 g of water at 20 °C. A solution at 20 °C holds 9.6 g per 100 g. Which is it, Luz?

   • Supersaturated
   • Saturated
   • Unsaturated
4. 4.

   Baking soda's limit is 8.2 g per 100 g at 10 °C. A slowly cooled, clear solution at 10 °C holds 11.0 g per 100 g. Which is it, Milo?

   • Supersaturated
   • Unsaturated
   • Saturated
5. 5.

   A saturated baking soda solution at 60 °C (16.5 g per 100 g) cools to 20 °C (9.6 g). What usually happens, Noah?

   • More baking soda dissolves as the water cools
   • Nothing, since the solid stays dissolved as it cools
   • About 6.9 g per 100 g of water crystallizes out
6. 6.

   Why do crystals often form when a hot saturated solution cools, Pia?

   • Most solids dissolve less when cold, so the extra comes out
   • The water itself freezes into crystals
   • Cold water dissolves more, which pushes the old crystals out of it
7. 7.

   A saturated salt solution warms from 25 °C to 60 °C. What happens to how much salt it can hold, Ren?

   • It can hold less, so salt crystallizes out of it as it warms up
   • It turns supersaturated as it warms
   • It can hold a little more, so it becomes slightly unsaturated
8. 8.

   How is a supersaturated solution usually reached, Tala?

   • By leaving undissolved crystals sitting on the bottom
   • By cooling a hot saturated solution gently, with no crystals
   • By stirring extra solid into a cup of cold water
9. 9.

   A clear supersaturated solution fills with crystals when the cup is tapped. Why, Zee?

   • The solution was unsaturated, so it could hold no more solute
   • The tap adds more solute to the cup from the air
   • The tap starts crystals, and the extra solute comes out
10. 10.

    After crystals form in a supersaturated solution, what is the liquid left behind, Ari?

    • Pure water, with no solute left in it
    • Still supersaturated, with the same extra solute dissolved
    • Saturated: it holds the most that can dissolve