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
500 mLc = 0.2 mol/L

What mass m of KNO3 (M = 101.1 g/mol) do you need to make 500 mL of a 0.2 mol/L solution?

V = 500 mLc = 0.2 mol/LM = 101.1 g/mol
m = g
2.Easy
250 mLc = 0.05 mol/L

What mass m of CaCl2 (M = 110.98 g/mol) do you need to make 250 mL of a 0.05 mol/L solution?

V = 250 mLc = 0.05 mol/LM = 110.98 g/mol
m = g
3.Medium
2 mol/LV1​0.25 mol/L200 mL

You need 200 mL of 0.25 mol/L solution and have a 2 mol/L stock solution. How much water Vwater do you add to the stock solution?

c1 = 2 mol/Lc2 = 0.25 mol/LV2 = 200 mL
Vwater = mL
4.Medium
1 mol/LV1​0.3 mol/L100 mL

You need 100 mL of 0.3 mol/L solution and have a 1 mol/L stock solution. How much water Vwater do you add to the stock solution?

c1 = 1 mol/Lc2 = 0.3 mol/LV2 = 100 mL
Vwater = mL
5.Hard
0.2 mol/L150 mL0.6 mol/L50 mLc = ?200 mL

150 mL of a 0.2 mol/L solution is mixed with 50 mL of a 0.6 mol/L solution of the same substance. Find the concentration c of the mixture (volumes are additive).

c1 = 0.2 mol/LV1 = 150 mLc2 = 0.6 mol/LV2 = 50 mL
c = mol/L
6.Hard
0.4 mol/L100 mL3 mol/L200 mLc = ?300 mL

100 mL of a 0.4 mol/L solution is mixed with 200 mL of a 3 mol/L solution of the same substance. Find the concentration c of the mixture (volumes are additive).

c1 = 0.4 mol/LV1 = 100 mLc2 = 3 mol/LV2 = 200 mL
c = mol/L

Answer key

  1. 1. m = 10.11 g
  2. 2. m = 1.387 g
  3. 3. Vwater = 175 mL
  4. 4. Vwater = 70 mL
  5. 5. c = 0.3 mol/L
  6. 6. c = 2.133 mol/L

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