Concentration as molarity

Answer Key - Grade 10 Science Worksheet - Building Confidence

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

1. 1.

   0.5 mol of salt is dissolved to make 2 L of solution. What is its molarity, to 0.01 M, Ari?

   0.25 M
2. 2.

   0.2 mol of salt is dissolved to make 0.25 L of solution. What is its molarity, to 0.01 M, Kira?

   0.8 M
3. 3.

   What does a 1 M salt solution mean, Jun?

   • 1 g of salt in each liter of the solution
   • 1 mol of salt added to 1 L of plain water
   • 1 mol of salt in each liter of solution
4. 4.

   What are the units of molarity, Luz?

   • Grams of solute per liter of the solution
   • Moles of solute per liter of water added
   • Moles of solute per liter of solution
5. 5.

   Why is molarity per liter of solution, not of water, Milo?

   • The solute adds volume, so the total counts
   • Molarity counts grams, so the volume hardly matters
   • Water and solution have the same volume each time
6. 6.

   How many liters is 250 mL, Noah?

   • 2.5 L
   • 250 L
   • 0.250 L
7. 7.

   0.10 mol of salt is dissolved to make 500 mL of solution. Which shows the molarity, Pia?

   • 0.10 mol ÷ 0.500 L = 0.20 M
   • 0.10 mol ÷ 500 L = 0.0002 M
   • 500 mL ÷ 0.10 mol = 5000 M
8. 8.

   A solution's volume is 750 mL. What volume goes into M = mol ÷ L, Ren?

   • 750 L
   • 7.5 L
   • 0.750 L
9. 9.

   Which is more concentrated: 0.5 M salt water or 0.2 M salt water, Zee?

   • They match, since both are salt water
   • The 0.5 M solution
   • The 0.2 M solution, since its number is smaller
10. 10.

    Two cups of 0.5 M sugar water hold 100 mL and 300 mL. Which is more concentrated, Esme?

    • The 100 mL cup, since it is smaller
    • The 300 mL cup, since it holds more sugar
    • Neither: both are 0.5 M