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
8.5 g KMnO4​V = 200 mL

8.5 g of KMnO4 (M = 158.03 g/mol) is dissolved in water to make 200 mL of solution. Find the molarity c.

m = 8.5 gM = 158.03 g/molV = 200 mL
c = mol/L
2.Easy
28.5 g KMnO4​V = 500 mL

28.5 g of KMnO4 (M = 158.03 g/mol) is dissolved in water to make 500 mL of solution. Find the molarity c.

m = 28.5 gM = 158.03 g/molV = 500 mL
c = mol/L
3.Medium
1 mol/LV1​ = ?0.4 mol/L100 mL

You need 100 mL of 0.4 mol/L solution and have a 1 mol/L stock solution. What volume V1 of stock solution do you need?

c1 = 1 mol/Lc2 = 0.4 mol/LV2 = 100 mL
V1 = mL
4.Medium
0.5 mol/LV1​ = ?0.4 mol/L1000 mL

You need 1000 mL of 0.4 mol/L solution and have a 0.5 mol/L stock solution. What volume V1 of stock solution do you need?

c1 = 0.5 mol/Lc2 = 0.4 mol/LV2 = 1000 mL
V1 = mL
5.Hard
0.1 mol/L150 mL3 mol/L500 mLc = ?650 mL

150 mL of a 0.1 mol/L solution is mixed with 500 mL of a 3 mol/L solution of the same substance. Find the concentration c of the mixture (volumes are additive).

c1 = 0.1 mol/LV1 = 150 mLc2 = 3 mol/LV2 = 500 mL
c = mol/L
6.Hard
0.5 mol/L300 mL0.05 mol/L100 mLc = ?400 mL

300 mL of a 0.5 mol/L solution is mixed with 100 mL of a 0.05 mol/L solution of the same substance. Find the concentration c of the mixture (volumes are additive).

c1 = 0.5 mol/LV1 = 300 mLc2 = 0.05 mol/LV2 = 100 mL
c = mol/L

Answer key

  1. 1. c = 0.2689 mol/L
  2. 2. c = 0.3607 mol/L
  3. 3. V1 = 40 mL
  4. 4. V1 = 800 mL
  5. 5. c = 2.331 mol/L
  6. 6. c = 0.3875 mol/L

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