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
23 g KMnO4​V = 750 mL

23 g of KMnO4 (M = 158.03 g/mol) is dissolved in water to make 750 mL of solution. Find the molarity c.

m = 23 gM = 158.03 g/molV = 750 mL
c = mol/L
2.Easy
100 mLc = 0.25 mol/L

What mass m of CaCl2 (M = 110.98 g/mol) do you need to make 100 mL of a 0.25 mol/L solution?

V = 100 mLc = 0.25 mol/LM = 110.98 g/mol
m = g
3.Medium
3 mol/LV1​ = ?0.3 mol/L1000 mL

You need 1000 mL of 0.3 mol/L solution and have a 3 mol/L stock solution. What volume V1 of stock solution do you need?

c1 = 3 mol/Lc2 = 0.3 mol/LV2 = 1000 mL
V1 = mL
4.Medium
5 mol/LV1​0.1 mol/L200 mL

You need 200 mL of 0.1 mol/L solution and have a 5 mol/L stock solution. How much water Vwater do you add to the stock solution?

c1 = 5 mol/Lc2 = 0.1 mol/LV2 = 200 mL
Vwater = mL
5.Hard
1 mol/L200 mL0.3 mol/L100 mLc = ?300 mL

200 mL of a 1 mol/L solution is mixed with 100 mL of a 0.3 mol/L solution of the same substance. Find the concentration c of the mixture (volumes are additive).

c1 = 1 mol/LV1 = 200 mLc2 = 0.3 mol/LV2 = 100 mL
c = mol/L
6.Hard
0.25 mol/L50 mL0.6 mol/L250 mLc = ?300 mL

50 mL of a 0.25 mol/L solution is mixed with 250 mL of a 0.6 mol/L solution of the same substance. Find the concentration c of the mixture (volumes are additive).

c1 = 0.25 mol/LV1 = 50 mLc2 = 0.6 mol/LV2 = 250 mL
c = mol/L

Answer key

  1. 1. c = 0.1941 mol/L
  2. 2. m = 2.775 g
  3. 3. V1 = 100 mL
  4. 4. Vwater = 196 mL
  5. 5. c = 0.7667 mol/L
  6. 6. c = 0.5417 mol/L

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