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 g KNO3​V = 250 mL

8 g of KNO3 (M = 101.1 g/mol) is dissolved in water to make 250 mL of solution. Find the molarity c.

m = 8 gM = 101.1 g/molV = 250 mL
c = mol/L
2.Easy
150 mLc = 0.5 mol/L

What mass m of KCl (M = 74.55 g/mol) do you need to make 150 mL of a 0.5 mol/L solution?

V = 150 mLc = 0.5 mol/LM = 74.55 g/mol
m = g
3.Medium
1.5 mol/LV1​ = ?0.4 mol/L1000 mL

You need 1000 mL of 0.4 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 = 0.4 mol/LV2 = 1000 mL
V1 = mL
4.Medium
5 mol/LV1​ = ?0.5 mol/L250 mL

You need 250 mL of 0.5 mol/L solution and have a 5 mol/L stock solution. What volume V1 of stock solution do you need?

c1 = 5 mol/Lc2 = 0.5 mol/LV2 = 250 mL
V1 = mL
5.Hard
0.2 mol/L200 mL0.05 mol/L500 mLc = ?700 mL

200 mL of a 0.2 mol/L solution is mixed with 500 mL of a 0.05 mol/L solution of the same substance. Find the concentration c of the mixture (volumes are additive).

c1 = 0.2 mol/LV1 = 200 mLc2 = 0.05 mol/LV2 = 500 mL
c = mol/L
6.Hard
0.25 mol/L150 mL1.2 mol/L250 mLc = ?400 mL

150 mL of a 0.25 mol/L solution is mixed with 250 mL of a 1.2 mol/L solution of the same substance. Find the concentration c of the mixture (volumes are additive).

c1 = 0.25 mol/LV1 = 150 mLc2 = 1.2 mol/LV2 = 250 mL
c = mol/L

Answer key

  1. 1. c = 0.3165 mol/L
  2. 2. m = 5.591 g
  3. 3. V1 = 266.7 mL
  4. 4. V1 = 25 mL
  5. 5. c = 0.09286 mol/L
  6. 6. c = 0.8438 mol/L

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