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
21.5 g Na2​CO3​V = 200 mL

21.5 g of Na2CO3 (M = 105.99 g/mol) is dissolved in water to make 200 mL of solution. Find the molarity c.

m = 21.5 gM = 105.99 g/molV = 200 mL
c = mol/L
2.Easy
31.5 g CuSO4​V = 150 mL

31.5 g of CuSO4 (M = 159.61 g/mol) is dissolved in water to make 150 mL of solution. Find the molarity c.

m = 31.5 gM = 159.61 g/molV = 150 mL
c = mol/L
3.Medium
0.5 mol/LV1​ = ?0.2 mol/L250 mL

You need 250 mL of 0.2 mol/L solution and have a 0.5 mol/L stock solution. What volume V1 of stock solution do you need?

c1 = 0.5 mol/Lc2 = 0.2 mol/LV2 = 250 mL
V1 = mL
4.Medium
6 mol/LV1​0.25 mol/L1000 mL

You need 1000 mL of 0.25 mol/L solution and have a 6 mol/L stock solution. How much water Vwater do you add to the stock solution?

c1 = 6 mol/Lc2 = 0.25 mol/LV2 = 1000 mL
Vwater = mL
5.Hard
0.25 mol/L100 mL0.6 mol/L50 mLc = ?150 mL

100 mL of a 0.25 mol/L solution is mixed with 50 mL of a 0.6 mol/L solution of the same substance. Find the concentration c of the mixture (volumes are additive).

c1 = 0.25 mol/LV1 = 100 mLc2 = 0.6 mol/LV2 = 50 mL
c = mol/L
6.Hard
0.4 mol/L200 mL0.6 mol/L250 mLc = ?450 mL

200 mL of a 0.4 mol/L solution is mixed with 250 mL of a 0.6 mol/L solution of the same substance. Find the concentration c of the mixture (volumes are additive).

c1 = 0.4 mol/LV1 = 200 mLc2 = 0.6 mol/LV2 = 250 mL
c = mol/L

Answer key

  1. 1. c = 1.014 mol/L
  2. 2. c = 1.316 mol/L
  3. 3. V1 = 100 mL
  4. 4. Vwater = 958.3 mL
  5. 5. c = 0.3667 mol/L
  6. 6. c = 0.5111 mol/L

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