Molarity & dilution worksheet with answers

Free printable Molarity & dilution worksheet: 6 problems from easy to exam level, with an answer key. Print it or save it as a PDF.

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1.Easy
20 g CaCl2​V = 500 mL

20 g of CaCl2 (M = 110.98 g/mol) is dissolved in water to make 500 mL of solution. Find the molarity c.

m = 20 gM = 110.98 g/molV = 500 mL
c = mol/L
2.Easy
1000 mLc = 0.5 mol/L

What mass m of KMnO4 (M = 158.03 g/mol) do you need to make 1000 mL of a 0.5 mol/L solution?

V = 1000 mLc = 0.5 mol/LM = 158.03 g/mol
m = g
3.Medium
1.5 mol/LV1​ = ?0.25 mol/L100 mL

You need 100 mL of 0.25 mol/L solution and have a 1.5 mol/L stock solution. What volume V1 of stock solution do you need?

c1 = 1.5 mol/Lc2 = 0.25 mol/LV2 = 100 mL
V1 = mL
4.Medium
3 mol/LV1​ = ?0.05 mol/L500 mL

You need 500 mL of 0.05 mol/L solution and have a 3 mol/L stock solution. What volume V1 of stock solution do you need?

c1 = 3 mol/Lc2 = 0.05 mol/LV2 = 500 mL
V1 = mL
5.Hard
0.8 mol/L100 mL0.05 mol/L200 mLc = ?300 mL

100 mL of a 0.8 mol/L solution is mixed with 200 mL of a 0.05 mol/L solution of the same substance. Find the concentration c of the mixture (volumes are additive).

c1 = 0.8 mol/LV1 = 100 mLc2 = 0.05 mol/LV2 = 200 mL
c = mol/L
6.Hard
2 mol/L250 mL3 mol/L100 mLc = ?350 mL

250 mL of a 2 mol/L solution is mixed with 100 mL of a 3 mol/L solution of the same substance. Find the concentration c of the mixture (volumes are additive).

c1 = 2 mol/LV1 = 250 mLc2 = 3 mol/LV2 = 100 mL
c = mol/L

Answer key

  1. 1. c = 0.3604 mol/L
  2. 2. m = 79.02 g
  3. 3. V1 = 16.67 mL
  4. 4. V1 = 8.333 mL
  5. 5. c = 0.3 mol/L
  6. 6. c = 2.286 mol/L

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