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
25.5 g Na2​CO3​V = 150 mL

25.5 g of Na2CO3 (M = 105.99 g/mol) is dissolved in water to make 150 mL of solution. Find the molarity c.

m = 25.5 gM = 105.99 g/molV = 150 mL
c = mol/L
2.Easy
25.5 g NaClV = 750 mL

25.5 g of NaCl (M = 58.44 g/mol) is dissolved in water to make 750 mL of solution. Find the molarity c.

m = 25.5 gM = 58.44 g/molV = 750 mL
c = mol/L
3.Medium
5 mol/LV1​ = ?0.1 mol/L200 mL

You need 200 mL of 0.1 mol/L solution and have a 5 mol/L stock solution. What volume V1 of stock solution do you need?

c1 = 5 mol/Lc2 = 0.1 mol/LV2 = 200 mL
V1 = mL
4.Medium
0.5 mol/LV1​0.2 mol/L100 mL

You need 100 mL of 0.2 mol/L solution and have a 0.5 mol/L stock solution. How much water Vwater do you add to the stock solution?

c1 = 0.5 mol/Lc2 = 0.2 mol/LV2 = 100 mL
Vwater = mL
5.Hard
0.1 mol/L150 mL0.05 mol/L250 mLc = ?400 mL

150 mL of a 0.1 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 = 0.1 mol/LV1 = 150 mLc2 = 0.05 mol/LV2 = 250 mL
c = mol/L
6.Hard
0.5 mol/L150 mL0.3 mol/L50 mLc = ?200 mL

150 mL of a 0.5 mol/L solution is mixed with 50 mL of a 0.3 mol/L solution of the same substance. Find the concentration c of the mixture (volumes are additive).

c1 = 0.5 mol/LV1 = 150 mLc2 = 0.3 mol/LV2 = 50 mL
c = mol/L

Answer key

  1. 1. c = 1.604 mol/L
  2. 2. c = 0.5818 mol/L
  3. 3. V1 = 4 mL
  4. 4. Vwater = 60 mL
  5. 5. c = 0.06875 mol/L
  6. 6. c = 0.45 mol/L

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