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
21.5 g CaCl2​V = 1000 mL

21.5 g of CaCl2 (M = 110.98 g/mol) is dissolved in water to make 1000 mL of solution. Find the molarity c.

m = 21.5 gM = 110.98 g/molV = 1000 mL
c = mol/L
2.Easy
18.5 g NaOHV = 150 mL

18.5 g of NaOH (M = 40 g/mol) is dissolved in water to make 150 mL of solution. Find the molarity c.

m = 18.5 gM = 40 g/molV = 150 mL
c = mol/L
3.Medium
4 mol/LV1​ = ?0.3 mol/L200 mL

You need 200 mL of 0.3 mol/L solution and have a 4 mol/L stock solution. What volume V1 of stock solution do you need?

c1 = 4 mol/Lc2 = 0.3 mol/LV2 = 200 mL
V1 = mL
4.Medium
4 mol/LV1​0.4 mol/L100 mL

You need 100 mL of 0.4 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 = 0.4 mol/LV2 = 100 mL
Vwater = mL
5.Hard
0.5 mol/L200 mL0.1 mol/L50 mLc = ?250 mL

200 mL of a 0.5 mol/L solution is mixed with 50 mL of a 0.1 mol/L solution of the same substance. Find the concentration c of the mixture (volumes are additive).

c1 = 0.5 mol/LV1 = 200 mLc2 = 0.1 mol/LV2 = 50 mL
c = mol/L
6.Hard
2 mol/L200 mL1.2 mol/L500 mLc = ?700 mL

200 mL of a 2 mol/L solution is mixed with 500 mL of a 1.2 mol/L solution of the same substance. Find the concentration c of the mixture (volumes are additive).

c1 = 2 mol/LV1 = 200 mLc2 = 1.2 mol/LV2 = 500 mL
c = mol/L

Answer key

  1. 1. c = 0.1937 mol/L
  2. 2. c = 3.083 mol/L
  3. 3. V1 = 15 mL
  4. 4. Vwater = 90 mL
  5. 5. c = 0.42 mol/L
  6. 6. c = 1.429 mol/L

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