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
7.5 g NaOHV = 1000 mL

7.5 g of NaOH (M = 40 g/mol) is dissolved in water to make 1000 mL of solution. Find the molarity c.

m = 7.5 gM = 40 g/molV = 1000 mL
c = mol/L
2.Easy
23.5 g C6​H12​O6​V = 1000 mL

23.5 g of C6H12O6 (M = 180.16 g/mol) is dissolved in water to make 1000 mL of solution. Find the molarity c.

m = 23.5 gM = 180.16 g/molV = 1000 mL
c = mol/L
3.Medium
1.5 mol/LV1​ = ?0.3 mol/L1000 mL

You need 1000 mL of 0.3 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 = 0.3 mol/LV2 = 1000 mL
V1 = mL
4.Medium
3 mol/LV1​0.3 mol/L1000 mL

You need 1000 mL of 0.3 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 = 0.3 mol/LV2 = 1000 mL
Vwater = mL
5.Hard
1 mol/L250 mL2.5 mol/L400 mLc = ?650 mL

250 mL of a 1 mol/L solution is mixed with 400 mL of a 2.5 mol/L solution of the same substance. Find the concentration c of the mixture (volumes are additive).

c1 = 1 mol/LV1 = 250 mLc2 = 2.5 mol/LV2 = 400 mL
c = mol/L
6.Hard
1.5 mol/L200 mL0.05 mol/L250 mLc = ?450 mL

200 mL of a 1.5 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 = 1.5 mol/LV1 = 200 mLc2 = 0.05 mol/LV2 = 250 mL
c = mol/L

Answer key

  1. 1. c = 0.1875 mol/L
  2. 2. c = 0.1304 mol/L
  3. 3. V1 = 200 mL
  4. 4. Vwater = 900 mL
  5. 5. c = 1.923 mol/L
  6. 6. c = 0.6944 mol/L

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