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
17.5 g CuSO4​V = 100 mL

17.5 g of CuSO4 (M = 159.61 g/mol) is dissolved in water to make 100 mL of solution. Find the molarity c.

m = 17.5 gM = 159.61 g/molV = 100 mL
c = mol/L
2.Easy
24.5 g Na2​CO3​V = 250 mL

24.5 g of Na2CO3 (M = 105.99 g/mol) is dissolved in water to make 250 mL of solution. Find the molarity c.

m = 24.5 gM = 105.99 g/molV = 250 mL
c = mol/L
3.Medium
6 mol/LV1​ = ?0.05 mol/L100 mL

You need 100 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 = 100 mL
V1 = mL
4.Medium
1.5 mol/LV1​ = ?0.05 mol/L200 mL

You need 200 mL of 0.05 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 = 0.05 mol/LV2 = 200 mL
V1 = mL
5.Hard
0.4 mol/L150 mL0.05 mol/L200 mLc = ?350 mL

150 mL of a 0.4 mol/L solution is mixed with 200 mL of a 0.05 mol/L solution of the same substance. Find the concentration c of the mixture (volumes are additive).

c1 = 0.4 mol/LV1 = 150 mLc2 = 0.05 mol/LV2 = 200 mL
c = mol/L
6.Hard
0.2 mol/L100 mL0.3 mol/L400 mLc = ?500 mL

100 mL of a 0.2 mol/L solution is mixed with 400 mL of a 0.3 mol/L solution of the same substance. Find the concentration c of the mixture (volumes are additive).

c1 = 0.2 mol/LV1 = 100 mLc2 = 0.3 mol/LV2 = 400 mL
c = mol/L

Answer key

  1. 1. c = 1.096 mol/L
  2. 2. c = 0.9246 mol/L
  3. 3. V1 = 0.8333 mL
  4. 4. V1 = 6.667 mL
  5. 5. c = 0.2 mol/L
  6. 6. c = 0.28 mol/L

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