Titration and Molarity Problems - Mr. Fischer



Titration and Molarity Problems

1. What is the molarity of a sodium hydroxide solution if 9 mL of the solution is titrated to the end point with 10mL of 0.20M Hydrochloric acid?

NaOH + HCl ( H2O + NaCl

0.010 L x 0.20 mole HCl = 0.002 moles

L

0.002 moles HCl x 1 mole NaOH = 0.002 moles NaOH

1 mole HCl

0.002 moles NaOH = 0.222 M

0.009 L

2. What is the molarity of a sodium hydroxide solution if 4.5 mL of the solution is titrated to the end point with 5mL of 0.083M acetic acid?

NaOH + HC2H3O2 ( H2O + NaC2H3O2

0.005 L x 0.083 mole HC2H3O2 = 0.000415 moles HC2H3O2

L

0.000415 moles HC2H3O2 x 1 mole NaOH = 0.000415 moles NaOH

1 mole HC2H3O2

0.000415 moles NaOH = 0.0922 M

0.0045 L

3. What is the molarity of a sodium hydroxide solution if 38 mL of the solution is titrated to the end point with 14mL of 0.75M sulfuric acid?

2NaOH + H2SO4 ( 2H2O + Na2SO4

0.014 L x 0.75 mole H2SO4 = 0.0105 moles H2SO4

L

0.0105 moles H2SO4 x 2 mole NaOH = 0.021 moles NaOH

1 mole H2SO4

0.021 moles NaOH = 0.553 M

0.038 L

4. If 24.6mL of a Ca(OH)2 solution is needed to neutralize 14.2 mL of 0.014M HC2H3O2, what is the concentration of the calcium hydroxide solution?

Ca(OH)2 + 2HC2H3O2 ( 2H2O + Ca(C2H3O2)2

0.0142 L x 0.014 mole HC2H3O2 = 0.0001988 moles HC2H3O2

L

0.0001988 moles HC2H3O2 x 1 mole Ca(OH)2 = 0.000994 moles Ca(OH)2

2 mole HC2H3O2

0.000994 moles Ca(OH)2 = 0.00404 M

0.0246 L

5. A 12.4 mL solution of H2SO4 is completely neutralized by 19.8 mL of 0.01M Ca(OH)2. What is the concentration of the H2SO4 solution?

Ca(OH)2 + H2SO4 ( 2H2O + Ca2SO4

0.0198 L x 0.01 mole H2SO4 = 0.0001988 moles H2SO4

L

0.0001988 moles H2SO4 x 1 mole Ca(OH)2 = 0.0001988 moles Ca(OH)2

1 mole H2SO4

0.0001988 moles Ca(OH)2 = 0.01596 M

0.0124 L

6. What volume of 0.12M Ba(OH)3 is needed to neutralize 12.2 mL of 0.25M HCl?

Ba(OH)3 + 3HCl ( 3H2O + BaCl3

0.0122 L x 0.25 mole HCl = 0.00305 moles HCl

L

0.00305 moles HCl x 1 mole Ba(OH)3 = 0.001016 moles Ba(OH)3

3 mole HCl

0.001016 mole Ba(OH)3 x 1 L = 0.00847 L

0.12 mole Ba(OH)3

7. A 55.0 mg sample of Al(OH)3 is reacted with 0.200M HCl. How many milliliters of the acid are needed to neutralize the Al(OH)3?

Al(OH)3 + 3HCl ( 3H2O + AlCl3

0.0550g x 1 mole Al(OH)3 = 0.0007053 mole Al(OH)3

77.98 g

0.0007053 mole Al(OH)3 x 3 mole HCl = 0.002115 moles HCl

1 mole Al(OH)3

0.002115 moles HCl x 1 L = 0.01058 L

0.20 moles HCl

8. What is the molarity of a solution made with 25 g of NaOH dissolved in 1.5L?

25 g x 1 mole NaOH = 0.625 moles NaOH

40 g

0.625 moles NaOH = 0.4166 M

1.5 L

9. What is the molarity of a solution made by dissolving 10g of KCl in 500mL of water?

10 g x 1 mole KCl = 0.134 moles KCl

74.55 g

0.134 moles KCl = 0.268 M

0.500 L

10. If you made 2 liters of a 6 M solution of NaCl how much NaCl would you need to use?

2 Liters x 6 moles NaCl = 12 moles NaCl

L

12 moles NaCl x 58.45 g = 701.4 g

mole NaCl

11. If you need to make 500mL of a 2 M solution of Ca(OH)2, how much Ca(OH)2 would you need to use?

0.500 Liters x 2 moles NaCl = 1 moles Ca(OH)2

L

1 moles Ca(OH)2 x 74.08 g = 74.08 g

mole Ca(OH)2

12. What is the molarity of a solution made by dissolving 3 moles of solute into 6 liters of solvent.

3 moles = 0.5 M

6 L

13. What is a solute substance dissolved in the solution.

14. What is a solvent the substance in which the solute is dissolved

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