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
32.5 g NaClV = 150 mL

32.5 g of NaCl (M = 58.44 g/mol) is dissolved in water to make 150 mL of solution. Find the molarity c.

m = 32.5 gM = 58.44 g/molV = 150 mL
c = mol/L
2.Easy
12 g NaClV = 100 mL

12 g of NaCl (M = 58.44 g/mol) is dissolved in water to make 100 mL of solution. Find the molarity c.

m = 12 gM = 58.44 g/molV = 100 mL
c = mol/L
3.Medium
5 mol/LV1​0.3 mol/L500 mL

You need 500 mL of 0.3 mol/L solution and have a 5 mol/L stock solution. How much water Vwater do you add to the stock solution?

c1 = 5 mol/Lc2 = 0.3 mol/LV2 = 500 mL
Vwater = mL
4.Medium
1.5 mol/LV1​ = ?0.25 mol/L100 mL

You need 100 mL of 0.25 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 = 0.25 mol/LV2 = 100 mL
V1 = mL
5.Hard
0.4 mol/L300 mL0.3 mol/L100 mLc = ?400 mL

300 mL of a 0.4 mol/L solution is mixed with 100 mL of a 0.3 mol/L solution of the same substance. Find the concentration c of the mixture (volumes are additive).

c1 = 0.4 mol/LV1 = 300 mLc2 = 0.3 mol/LV2 = 100 mL
c = mol/L
6.Hard
1.5 mol/L100 mL0.3 mol/L200 mLc = ?300 mL

100 mL of a 1.5 mol/L solution is mixed with 200 mL of a 0.3 mol/L solution of the same substance. Find the concentration c of the mixture (volumes are additive).

c1 = 1.5 mol/LV1 = 100 mLc2 = 0.3 mol/LV2 = 200 mL
c = mol/L

Answer key

  1. 1. c = 3.708 mol/L
  2. 2. c = 2.053 mol/L
  3. 3. Vwater = 470 mL
  4. 4. V1 = 16.67 mL
  5. 5. c = 0.375 mol/L
  6. 6. c = 0.7 mol/L

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