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CHAPTER 5 Reactions in Aqueous Solution. Homework for Chapter 5 problems posted due Feb 26 Know: Table 5.2, pg 182 Use: Figure 5.3, page 179. Road Map. Where we were Total & Net ionic equations Acids and bases Precipitation reactions Where we are going Classifying reactions
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CHAPTER 5 Reactions in Aqueous Solution • Homework for Chapter 5 • problems posted • due Feb 26 • Know: Table 5.2, pg 182 • Use: Figure 5.3, page 179 Chem 105 Chpt 4 Lsn 12
Road Map • Where we were • Total & Net ionic equations • Acids and bases • Precipitation reactions • Where we are going • Classifying reactions • Oxidation reactions • Measuring concentrations of compounds in solution • pH • Stoichiometry of reactions in aqueous solution Chem 105 Chpt 4 Lsn 12
Practice Problem 10 - 4 • Calcium chloride and potassium phosphate combine to form calcium phosphate and potassium chloride. • Write the molecular equation 3 CaCl2(aq) + 2 K3PO4(aq) → Ca3PO4(s) + 6 KCl(aq) • Write the Total Ionic and Net Ionic equations Chem 105 Chpt 4 Lsn 12
3 CaCl2(aq) + 2 K3PO4(aq) → Ca3PO4(s) + 6 KCl(aq) • Write the Total Ionic and Net Ionic equations • Combining 5 grams CaCl2 with 3.5 grams of K3PO4 produced only a 67% yield of KCl. • What is the limiting reactant? • What mass of product did you make? Chem 105 Chpt 4 Lsn 12
5.4 Acid-Base Reactions: Acid-Base Titrations • What volume of 0.1292 M Ba(OH)2 would neutralize 50.00 mL of the HCl solution standardized in the preceding sample problem (4.5) ? Chem 105 Chpt 4 Lsn 12
Classifying reactions (5-29) • Balance the following reactions (√) and then classify each as precipitation, acid-base, or gas-forming reaction. • a) Ba(OH)2 (aq) + 2 HCl (aq) BaCl2 (aq) + 2 H2O (l) • b) 2 HNO3 (aq) + CoCO3 (s) Co(NO3)2 (aq) + H2O (l) + CO2 (g) • c) 2 Na3PO4 (aq) + 3 Cu(NO3)2 (aq) Cu3(PO4)2 (s) + 6 NaNO3 (aq) Chem 105 Chpt 4 Lsn 12
Oxidation NumbersReDox Reactions • 5-36 (pg 225) Oxidation number • PF6- H2AsO4- UO2- N2O5 POCl5XeO42- • 5-37 (a) • Zn (s) Zn2+ (aq) 0 2+ (ox) • N5+ N4+ (aq) 5+ 4+ (red) • O2- O2- (aq) no change • H+ H+ (aq) no change • Oxidation (loss of e-) • Reduction (gain of e-) Chem 105 Chpt 4 Lsn 12
5.8 Measuring Concentrations • How many moles of H+(aq) are present in 451 mL of 3.20 M hydrobromic acid? • 5-46 What volume 2.06 M KMnO4, in liters, contains 322 g of solute? • 0.989 L Chem 105 Chpt 4 Lsn 12
Preparing solutions • 5-50 What mass of oxalic acid, H2C2O4, is required to prepare 250. mL of a solution that has a concentration or 0.15 M H2C2O4? • 3.4 g H2C2O4 Chem 105 Chpt 4 Lsn 12
pH • pH = -log [H+] • pOH = - log [OH-] • Kw = [H+][OH-] = 1.00 x 10-14 • pH + pOH = 14 • 5-56 A saturated solution of milk of magnesia, Mg(OH)2, has a pH of 10.5. What is the hydrogen ion concentration of the solution? Is the solution acidic or basic? Chem 105 Chpt 4 Lsn 12
Stoichiometry of Reactions in Solution • 5-64 Hydrazine, N2H4, a base like ammonia, can react with an acid such as sulfuric acid. What mass of hydrazine reacts with 250. mL of 0.146 M H2SO4? 2 N2H4 (aq) + H2SO4 (aq) 2 N2H5+ (aq) + SO42- (aq) • 2.34 g N2H4 Chem 105 Chpt 4 Lsn 12
Challenge • 5- 75 • 5- 74 Chem 105 Chpt 4 Lsn 12
Next Lesson • Chapter 6 Chem 105 Chpt 4 Lsn 12