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
31 g KClV = 200 mL

31 g of KCl (M = 74.55 g/mol) is dissolved in water to make 200 mL of solution. Find the molarity c.

m = 31 gM = 74.55 g/molV = 200 mL
c = mol/L
2.Easy
100 mLc = 0.1 mol/L

What mass m of CuSO4 (M = 159.61 g/mol) do you need to make 100 mL of a 0.1 mol/L solution?

V = 100 mLc = 0.1 mol/LM = 159.61 g/mol
m = g
3.Medium
6 mol/LV1​ = ?0.4 mol/L200 mL

You need 200 mL of 0.4 mol/L solution and have a 6 mol/L stock solution. What volume V1 of stock solution do you need?

c1 = 6 mol/Lc2 = 0.4 mol/LV2 = 200 mL
V1 = mL
4.Medium
0.5 mol/LV1​ = ?0.05 mol/L100 mL

You need 100 mL of 0.05 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 = 0.05 mol/LV2 = 100 mL
V1 = mL
5.Hard
0.8 mol/L300 mL0.3 mol/L250 mLc = ?550 mL

300 mL of a 0.8 mol/L solution is mixed with 250 mL of a 0.3 mol/L solution of the same substance. Find the concentration c of the mixture (volumes are additive).

c1 = 0.8 mol/LV1 = 300 mLc2 = 0.3 mol/LV2 = 250 mL
c = mol/L
6.Hard
1.5 mol/L150 mL0.6 mol/L200 mLc = ?350 mL

150 mL of a 1.5 mol/L solution is mixed with 200 mL of a 0.6 mol/L solution of the same substance. Find the concentration c of the mixture (volumes are additive).

c1 = 1.5 mol/LV1 = 150 mLc2 = 0.6 mol/LV2 = 200 mL
c = mol/L

Answer key

  1. 1. c = 2.079 mol/L
  2. 2. m = 1.596 g
  3. 3. V1 = 13.33 mL
  4. 4. V1 = 10 mL
  5. 5. c = 0.5727 mol/L
  6. 6. c = 0.9857 mol/L

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