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
1 g Na2​CO3​V = 1000 mL

1 g of Na2CO3 (M = 105.99 g/mol) is dissolved in water to make 1000 mL of solution. Find the molarity c.

m = 1 gM = 105.99 g/molV = 1000 mL
c = mol/L
2.Easy
11.5 g KClV = 750 mL

11.5 g of KCl (M = 74.55 g/mol) is dissolved in water to make 750 mL of solution. Find the molarity c.

m = 11.5 gM = 74.55 g/molV = 750 mL
c = mol/L
3.Medium
4 mol/LV1​ = ?0.3 mol/L100 mL

You need 100 mL of 0.3 mol/L solution and have a 4 mol/L stock solution. What volume V1 of stock solution do you need?

c1 = 4 mol/Lc2 = 0.3 mol/LV2 = 100 mL
V1 = mL
4.Medium
5 mol/LV1​ = ?0.2 mol/L250 mL

You need 250 mL of 0.2 mol/L solution and have a 5 mol/L stock solution. What volume V1 of stock solution do you need?

c1 = 5 mol/Lc2 = 0.2 mol/LV2 = 250 mL
V1 = mL
5.Hard
1 mol/L300 mL0.75 mol/L100 mLc = ?400 mL

300 mL of a 1 mol/L solution is mixed with 100 mL of a 0.75 mol/L solution of the same substance. Find the concentration c of the mixture (volumes are additive).

c1 = 1 mol/LV1 = 300 mLc2 = 0.75 mol/LV2 = 100 mL
c = mol/L
6.Hard
0.1 mol/L250 mL1.2 mol/L400 mLc = ?650 mL

250 mL of a 0.1 mol/L solution is mixed with 400 mL of a 1.2 mol/L solution of the same substance. Find the concentration c of the mixture (volumes are additive).

c1 = 0.1 mol/LV1 = 250 mLc2 = 1.2 mol/LV2 = 400 mL
c = mol/L

Answer key

  1. 1. c = 0.009435 mol/L
  2. 2. c = 0.2057 mol/L
  3. 3. V1 = 7.5 mL
  4. 4. V1 = 10 mL
  5. 5. c = 0.9375 mol/L
  6. 6. c = 0.7769 mol/L

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