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
4.5 g NaClV = 250 mL

4.5 g of NaCl (M = 58.44 g/mol) is dissolved in water to make 250 mL of solution. Find the molarity c.

m = 4.5 gM = 58.44 g/molV = 250 mL
c = mol/L
2.Easy
11 g Na2​CO3​V = 750 mL

11 g of Na2CO3 (M = 105.99 g/mol) is dissolved in water to make 750 mL of solution. Find the molarity c.

m = 11 gM = 105.99 g/molV = 750 mL
c = mol/L
3.Medium
2 mol/LV1​ = ?0.2 mol/L1000 mL

You need 1000 mL of 0.2 mol/L solution and have a 2 mol/L stock solution. What volume V1 of stock solution do you need?

c1 = 2 mol/Lc2 = 0.2 mol/LV2 = 1000 mL
V1 = mL
4.Medium
1 mol/LV1​ = ?0.25 mol/L250 mL

You need 250 mL of 0.25 mol/L solution and have a 1 mol/L stock solution. What volume V1 of stock solution do you need?

c1 = 1 mol/Lc2 = 0.25 mol/LV2 = 250 mL
V1 = mL
5.Hard
2 mol/L150 mL0.05 mol/L500 mLc = ?650 mL

150 mL of a 2 mol/L solution is mixed with 500 mL of a 0.05 mol/L solution of the same substance. Find the concentration c of the mixture (volumes are additive).

c1 = 2 mol/LV1 = 150 mLc2 = 0.05 mol/LV2 = 500 mL
c = mol/L
6.Hard
2 mol/L100 mL0.75 mol/L50 mLc = ?150 mL

100 mL of a 2 mol/L solution is mixed with 50 mL of a 0.75 mol/L solution of the same substance. Find the concentration c of the mixture (volumes are additive).

c1 = 2 mol/LV1 = 100 mLc2 = 0.75 mol/LV2 = 50 mL
c = mol/L

Answer key

  1. 1. c = 0.308 mol/L
  2. 2. c = 0.1384 mol/L
  3. 3. V1 = 100 mL
  4. 4. V1 = 62.5 mL
  5. 5. c = 0.5 mol/L
  6. 6. c = 1.583 mol/L

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