1. 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

2. 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

3. 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

4. 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

5. 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

6. 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 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

7. 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 M H2SO4?
2 N2H4 (aq) + H2SO4 (aq) 
2 N2H5+ (aq) + SO42- (aq)
2.34 g N2H4
Chem 105 Chpt 4 Lsn 12

8. 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
M NaOH
% Fe
g C6H8O6
Chem 105 Chpt 4 Lsn 12

9. 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

10. 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

11. Next Lesson
Chapter 6
Chem 105 Chpt 4 Lsn 12