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
16 g KClV = 1000 mL

16 g of KCl (M = 74.55 g/mol) is dissolved in water to make 1000 mL of solution. Find the molarity c.

m = 16 gM = 74.55 g/molV = 1000 mL
c = mol/L
2.Easy
14 g KNO3​V = 100 mL

14 g of KNO3 (M = 101.1 g/mol) is dissolved in water to make 100 mL of solution. Find the molarity c.

m = 14 gM = 101.1 g/molV = 100 mL
c = mol/L
3.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. How much water Vwater do you add to the stock solution?

c1 = 3 mol/Lc2 = 0.4 mol/LV2 = 500 mL
Vwater = mL
4.Medium
2.5 mol/LV1​ = ?0.25 mol/L1000 mL

You need 1000 mL of 0.25 mol/L solution and have a 2.5 mol/L stock solution. What volume V1 of stock solution do you need?

c1 = 2.5 mol/Lc2 = 0.25 mol/LV2 = 1000 mL
V1 = mL
5.Hard
0.1 mol/L250 mL3 mol/L200 mLc = ?450 mL

250 mL of a 0.1 mol/L solution is mixed with 200 mL of a 3 mol/L solution of the same substance. Find the concentration c of the mixture (volumes are additive).

c1 = 0.1 mol/LV1 = 250 mLc2 = 3 mol/LV2 = 200 mL
c = mol/L
6.Hard
2 mol/L100 mL1.2 mol/L200 mLc = ?300 mL

100 mL of a 2 mol/L solution is mixed with 200 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 = 100 mLc2 = 1.2 mol/LV2 = 200 mL
c = mol/L

Answer key

  1. 1. c = 0.2146 mol/L
  2. 2. c = 1.385 mol/L
  3. 3. Vwater = 433.3 mL
  4. 4. V1 = 100 mL
  5. 5. c = 1.389 mol/L
  6. 6. c = 1.467 mol/L

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