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
28 g NaClV = 150 mL

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

m = 28 gM = 58.44 g/molV = 150 mL
c = mol/L
2.Easy
14.5 g NaOHV = 1000 mL

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

m = 14.5 gM = 40 g/molV = 1000 mL
c = mol/L
3.Medium
1 mol/LV1​ = ?0.05 mol/L250 mL

You need 250 mL of 0.05 mol/L solution and have a 1 mol/L stock solution. What volume V1 of stock solution do you need?

c1 = 1 mol/Lc2 = 0.05 mol/LV2 = 250 mL
V1 = mL
4.Medium
2.5 mol/LV1​ = ?0.3 mol/L1000 mL

You need 1000 mL of 0.3 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 = 0.3 mol/LV2 = 1000 mL
V1 = mL
5.Hard
1 mol/L100 mL0.1 mol/L250 mLc = ?350 mL

100 mL of a 1 mol/L solution is mixed with 250 mL of a 0.1 mol/L solution of the same substance. Find the concentration c of the mixture (volumes are additive).

c1 = 1 mol/LV1 = 100 mLc2 = 0.1 mol/LV2 = 250 mL
c = mol/L
6.Hard
0.5 mol/L250 mL0.1 mol/L500 mLc = ?750 mL

250 mL of a 0.5 mol/L solution is mixed with 500 mL of a 0.1 mol/L solution of the same substance. Find the concentration c of the mixture (volumes are additive).

c1 = 0.5 mol/LV1 = 250 mLc2 = 0.1 mol/LV2 = 500 mL
c = mol/L

Answer key

  1. 1. c = 3.194 mol/L
  2. 2. c = 0.3625 mol/L
  3. 3. V1 = 12.5 mL
  4. 4. V1 = 120 mL
  5. 5. c = 0.3571 mol/L
  6. 6. c = 0.2333 mol/L

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