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
11.5 g KMnO4​V = 750 mL

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

m = 11.5 gM = 158.03 g/molV = 750 mL
c = mol/L
2.Easy
39 g Na2​CO3​V = 1000 mL

39 g of Na2CO3 (M = 105.99 g/mol) is dissolved in water to make 1000 mL of solution. Find the molarity c.

m = 39 gM = 105.99 g/molV = 1000 mL
c = mol/L
3.Medium
4 mol/LV1​0.25 mol/L200 mL

You need 200 mL of 0.25 mol/L solution and have a 4 mol/L stock solution. How much water Vwater do you add to the stock solution?

c1 = 4 mol/Lc2 = 0.25 mol/LV2 = 200 mL
Vwater = mL
4.Medium
6 mol/LV1​ = ?0.05 mol/L1000 mL

You need 1000 mL of 0.05 mol/L solution and have a 6 mol/L stock solution. What volume V1 of stock solution do you need?

c1 = 6 mol/Lc2 = 0.05 mol/LV2 = 1000 mL
V1 = mL
5.Hard
0.1 mol/L50 mL0.05 mol/L250 mLc = ?300 mL

50 mL of a 0.1 mol/L solution is mixed with 250 mL of a 0.05 mol/L solution of the same substance. Find the concentration c of the mixture (volumes are additive).

c1 = 0.1 mol/LV1 = 50 mLc2 = 0.05 mol/LV2 = 250 mL
c = mol/L
6.Hard
0.8 mol/L200 mL3 mol/L400 mLc = ?600 mL

200 mL of a 0.8 mol/L solution is mixed with 400 mL of a 3 mol/L solution of the same substance. Find the concentration c of the mixture (volumes are additive).

c1 = 0.8 mol/LV1 = 200 mLc2 = 3 mol/LV2 = 400 mL
c = mol/L

Answer key

  1. 1. c = 0.09703 mol/L
  2. 2. c = 0.368 mol/L
  3. 3. Vwater = 187.5 mL
  4. 4. V1 = 8.333 mL
  5. 5. c = 0.05833 mol/L
  6. 6. c = 2.267 mol/L

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