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
100 mLc = 0.5 mol/L

What mass m of KNO3 (M = 101.1 g/mol) do you need to make 100 mL of a 0.5 mol/L solution?

V = 100 mLc = 0.5 mol/LM = 101.1 g/mol
m = g
2.Easy
40 g NaClV = 200 mL

40 g of NaCl (M = 58.44 g/mol) is dissolved in water to make 200 mL of solution. Find the molarity c.

m = 40 gM = 58.44 g/molV = 200 mL
c = mol/L
3.Medium
6 mol/LV1​0.25 mol/L200 mL

You need 200 mL of 0.25 mol/L solution and have a 6 mol/L stock solution. How much water Vwater do you add to the stock solution?

c1 = 6 mol/Lc2 = 0.25 mol/LV2 = 200 mL
Vwater = mL
4.Medium
1 mol/LV1​0.1 mol/L200 mL

You need 200 mL of 0.1 mol/L solution and have a 1 mol/L stock solution. How much water Vwater do you add to the stock solution?

c1 = 1 mol/Lc2 = 0.1 mol/LV2 = 200 mL
Vwater = mL
5.Hard
1 mol/L100 mL0.6 mol/L400 mLc = ?500 mL

100 mL of a 1 mol/L solution is mixed with 400 mL of a 0.6 mol/L solution of the same substance. Find the concentration c of the mixture (volumes are additive).

c1 = 1 mol/LV1 = 100 mLc2 = 0.6 mol/LV2 = 400 mL
c = mol/L
6.Hard
0.25 mol/L50 mL0.75 mol/L250 mLc = ?300 mL

50 mL of a 0.25 mol/L solution is mixed with 250 mL of a 0.75 mol/L solution of the same substance. Find the concentration c of the mixture (volumes are additive).

c1 = 0.25 mol/LV1 = 50 mLc2 = 0.75 mol/LV2 = 250 mL
c = mol/L

Answer key

  1. 1. m = 5.055 g
  2. 2. c = 3.422 mol/L
  3. 3. Vwater = 191.7 mL
  4. 4. Vwater = 180 mL
  5. 5. c = 0.68 mol/L
  6. 6. c = 0.6667 mol/L

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