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
19 g KNO3​V = 500 mL

19 g of KNO3 (M = 101.1 g/mol) is dissolved in water to make 500 mL of solution. Find the molarity c.

m = 19 gM = 101.1 g/molV = 500 mL
c = mol/L
2.Easy
500 mLc = 0.25 mol/L

What mass m of KMnO4 (M = 158.03 g/mol) do you need to make 500 mL of a 0.25 mol/L solution?

V = 500 mLc = 0.25 mol/LM = 158.03 g/mol
m = g
3.Medium
3 mol/LV1​0.25 mol/L100 mL

You need 100 mL of 0.25 mol/L solution and have a 3 mol/L stock solution. How much water Vwater do you add to the stock solution?

c1 = 3 mol/Lc2 = 0.25 mol/LV2 = 100 mL
Vwater = mL
4.Medium
3 mol/LV1​ = ?0.4 mol/L500 mL

You need 500 mL of 0.4 mol/L solution and have a 3 mol/L stock solution. What volume V1 of stock solution do you need?

c1 = 3 mol/Lc2 = 0.4 mol/LV2 = 500 mL
V1 = mL
5.Hard
1 mol/L150 mL0.05 mol/L400 mLc = ?550 mL

150 mL of a 1 mol/L solution is mixed with 400 mL of a 0.05 mol/L solution of the same substance. Find the concentration c of the mixture (volumes are additive).

c1 = 1 mol/LV1 = 150 mLc2 = 0.05 mol/LV2 = 400 mL
c = mol/L
6.Hard
2 mol/L300 mL0.05 mol/L100 mLc = ?400 mL

300 mL of a 2 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 = 2 mol/LV1 = 300 mLc2 = 0.05 mol/LV2 = 100 mL
c = mol/L

Answer key

  1. 1. c = 0.3759 mol/L
  2. 2. m = 19.75 g
  3. 3. Vwater = 91.67 mL
  4. 4. V1 = 66.67 mL
  5. 5. c = 0.3091 mol/L
  6. 6. c = 1.512 mol/L

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