Reactions in Aqueous Solutions II: Calculations Chapter 11 Reactions in Aqueous Solutions II: Calculations 1 1 1 1 1 1 1 1

Calculations Involving Molarity Example 11-1: If 100.0 mL of 1.00 M NaOH and 100.0 mL of 0.500 M H2SO4 solutions are mixed, what will the concentration of the resulting solution be? What is the balanced reaction? It is very important that we always use a balanced chemical reaction when doing stoichiometric calculations. 2 2 2 2 3 3 3 3

Calculations Involving Molarity Reaction Ratio: 2 mmol 1 mmol Before Reaction: 100 mmol 50 mmol 0 mmol After 3 3 3 3 4 4 4 4

Calculations Involving Molarity What is the total volume of solution? 100.0 mL + 100.0 mL = 200.0 mL What is the sodium sulfate amount, in mmol? 50.0 mmol What is the molarity of the solution? M = 50 mmol/200 mL = 0.250 M Na2SO4 4 4 4 4 5 5 5 5

Calculations Involving Molarity Example 11-2: If 130.0 mL of 1.00 M KOH and 100.0 mL of 0.500 M H2SO4 solutions are mixed, what will be the concentration of KOH and K2SO4 in the resulting solution? What is the balanced reaction? 5 5 5 6 6 6 6

Calculations Involving Molarity Reaction Ratio: 2 mmol 1 mmol Before Reaction: 130 mmol 50 mmol 0 mmol After 30 mmol 100 mmol 6 6 6 7 7 7 7

Calculations Involving Molarity What is the total volume of solution? 130.0 mL + 100.0 mL = 230.0 mL What are the potassium hydroxide and potassium sulfate amounts? 30.0 mmol & 50.0 mmol What is the molarity of the solution? M = 30.0 mmol/230.0 mL = 0.130 M KOH M = 50.0 mmol/230.0 mL = 0.217 M K2SO4 7 7 7 8 8 8 8

Calculations Involving Molarity Example 11-3: What volume of 0.750 M NaOH solution would be required to completely neutralize 100 mL of 0.250 M H3PO4? 8 8 8 9 9 9 9

Calculations for Acid-Base Titrations Example 11-4: Calculate the molarity of a NaOH solution if 27.3 mL of it reacts with 0.4084 g of KHP. 12 12 13 13 13 13

Calculations for Acid-Base Titrations Example 11-5: Calculate the molarity of a sulfuric acid solution if 23.2 mL of it reacts with 0.212 g of Na2CO3. 14 14 15 15 15 15

Calculations for Acid-Base Titrations Example 11-6: An impure sample of potassium hydrogen phthalate, KHP, had a mass of 0.884 g. It was dissolved in water and titrated with 31.5 mL of 0.100 M NaOH solution. Calculate the percent purity of the KHP sample. NaOH + KHP → NaKP + H2O 16 16 17 17 17 17

Balancing Redox Reactions Example 11-12: Tin (II) ions are oxidized to tin (IV) by bromine. Use the half reaction method to write and balance the net ionic equation. 40 39 41 41 41

Balancing Redox Reactions 41 42 43 43 43

Balancing Redox Reactions 42 43 44 44 44

Balancing Redox Reactions Example 11-13: Dichromate ions oxidize iron (II) ions to iron (III) ions and are reduced to chromium (III) ions in acidic solution. Write and balance the net ionic equation for the reaction. 44 43 45 45 45

Balancing Redox Reactions 44 45 47 47 46

Balancing Redox Reactions 46 47 49 49 48

Balancing Redox Reactions 48 49 51 51 50

Balancing Redox Reactions 50 51 53 53 52

Calculations for Redox Titrations Example 11-16: What volume of 0.200 M KMnO4 is required to oxidize 35.0 mL of 0.150 M HCl? The balanced reaction is: 52 51 54 54 53

Calculations for Redox Titrations Example 11-17: A volume of 40.0 mL of iron (II) sulfate is oxidized to iron (III) by 20.0 mL of 0.100 M potassium dichromate solution. What is the concentration of the iron (II) sulfate solution? 54 53 56 56 55

Synthesis Question