Dilution calculations

Answer Key - Grade 10 Science Worksheet

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

1. 1.

   0.4 L of 1.5 M salt water is diluted to 0.5 M. What final volume does it reach, to 0.01 L, Bo?

   1.2 L
2. 2.

   100 mL of 1.0 M sugar water is diluted to 400 mL. What is the new molarity, Kira?

   • 1.0 M, as the sugar is the same
   • 0.25 M
   • 4.0 M, from 1.0 × 400 ÷ 100
3. 3.

   0.20 L of 0.50 M salt water is diluted to 1.00 L. What is the new molarity, Luz?

   • 0.10 M
   • 2.5 M, from 0.50 × 1.00 ÷ 0.20
   • 0.50 M, as the salt is the same
4. 4.

   50 mL of 3.0 M salt water is diluted to 150 mL. What is the new molarity, Milo?

   • 9.0 M, from 3.0 × 150 ÷ 50
   • 1.0 M
   • 3.0 M
5. 5.

   0.50 L of 0.40 M salt water is diluted to 2.0 L. How many moles of salt are in it before and after, Noah?

   • 0.20 mol before and 0.05 mol after
   • 0.20 mol before and 0.80 mol after
   • 0.20 mol both times
6. 6.

   Which stays the same when sugar water is diluted, Pia?

   • The moles of sugar
   • The volume of the solution
   • The molarity of the sugar water
7. 7.

   After a dilution, a student finds more moles of salt than before. What went wrong, Ren?

   • Dilution can't add solute, so the math is off
   • Nothing: the added water brings more salt moles
   • Nothing: dilution doubles the moles of salt
8. 8.

   0.25 L of 2.0 M salt water is diluted to 0.50 M. What final volume, and how much water was added, Tala?

   • 1.0 L of water added on top of the 0.25 L
   • 1.0 L in all, so 0.75 L of water
   • 0.0625 L in all, from 0.50 × 0.25 ÷ 2.0
9. 9.

   0.10 L of 1.2 M sugar water is diluted to 0.30 M. How much water is added, Zee?

   • 0.30 L
   • 0.40 L, the final volume itself
   • 0.025 L, from 0.30 × 0.10 ÷ 1.2
10. 10.

    Why isn't V₂ the amount of water to add, Ari?

    • V₂ is the volume of the solute alone
    • V₂ is the water added, since water is the one thing that changes
    • V₂ includes the start, so water = V₂ − V₁