Reactions in Aqueous Solution 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 Where we are going Classifying reactions Oxidation reactions Where we are going Measuring concentrations of compounds in solution pH Stoichiometry of reactions in aqueous solution Chem 105 Chpt 4 Lsn 12

Oxidation Numbers ReDox Reactions 4 Fe(OH)2 (s) + 2 H2O (l) + O2 (g)  4 Fe(OH)3 (aq) Write the oxidation numbers of each element on each side. Identify the species oxidized and the one reduced Oxidation (loss of e-) Reduction (gain of e-) Chem 105 Chpt 4 Lsn 12

5.8 Measuring Concentrations Chapter 01: Matter and Measurement 5.8 Measuring Concentrations How many moles of H+(aq) are present in 451 mL of 3.20 M hydrobromic acid? 1.44 mol H+ 5-46 What volume 2.06 M KMnO4, in liters, contains 322 g of solute? 0.989 L Follow-Up Problem 4.2 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? 3 x 10-11 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

Chapter 01: Matter and Measurement Challenge 5- 72 5- 75 5-76 First 3 teams (max 4 members) to correctly solve the problem receive 5 bonus points 5.72 0.167 M NaOH 5.75 12.8 % Fe 5.76 0.500 g C6H8O6 Chem 105 Chpt 4 Lsn 12

Chapter 6 Principles of Reactivity: Energy and Chemical Reactivity Energy transfer Calorie burning, gravitational, chemical, electrostatic Heat- mostly seen in chemical processes Thermodynamics – transfer of heat between objects; science of heat and work Energy: Some basic principles – capacity to do work Kinetic – energy of motion Potential – energy of position Conservation of energy (aka First law of thermodynamics) Total energy of universe is constant Chem 105 Chpt 4 Lsn 12

Energy: Some basic principles – capacity to do work Systems and surroundings Thermal equilibrium – system and surroundings reach same temperature Exothermic (heat out of system) Endothermic (heat into system) Chem 105 Chpt 4 Lsn 12

Next Lesson Chapter 6 Chem 105 Chpt 4 Lsn 12