AP Chemistry: Chapter 4 Chapter 4: Aqueous Reactions and Solution Stoichiometry This section presents the fundamental quantitative skills students will need for the rest of the course. College Board Performance Objectives: • • • • • Calculate moles of solute, volume of solution, or molarity of the solution from the other two. Recognize and solve dilution problems. Calculate the volume of a certain molarity solution required to react with another solution of known molarity. Calculate the mass of a substance that would be required to react with a given volume of a solution of known molarity. Calculate mass of solute or concentration of an unknown solution from titration data. College Board Lab Objectives: • • To become familiar with chemical formulas (empirical and molecular) and how they are obtained experimentally. Learn some basic lab procedures, the chemistry of copper, and the concept of percent yield. Troubleshooting Tips/Error Traps: Reaction stoichiometry requires a correct, balanced chemical equation. Key Terms: aqueous solution, p. 121 electrolyte p. 122 nonelectrolyte, p. 122 strong and weak electrolytes p. 124 chemical equilbrium, p. 125 solvation p. 123 precipitate/precipitation reactions p. 126 solubility, p. 127 metathesis reactions, p. 128 molecular, ionic and net ionic equations, p. 129 spectator ions, p. 129 acids and bases, p. 131 (strong and weak) neutralization reaction, p. 134 salt, p. 134 oxidation-reduction reactions, p. 137 oxidation numbers, p. 139 displacement reactions, p. 140 activity series, p. 142 molarity, p. 146 dilution, p. 148 titration, p. 152 standard solution, p. 152 equivalence point, p. 152 indicators, p. 153 endpoint p. 153 CHAPTER 4 ASSIGNMENTS: Summarize: Read Chapter 4 and write a short summary of each of the topics, 4.1-4.6 in your own words. Homework Exercises: Critical thinking questions and end-of-chapter activities are included in these exercises. • • pp. 157–165, Visualizing Concepts: # 4.1, 4.5, 4.9, Electrolytes: #4.15, 4.17, Precipitation Reactions: #4.19, 4.12, 4.23, 4.25, 4.27, Acid-Base Reactions: #4.29, 4.31, 4.35, 4.37, 4.39, 4.41, 4.43, Oxidation-Reduction Reactions: #4.45, 4.47, 4.49, 4.51, 4.52, 4.53, 4.55, 4.57, Solution Composition: 4.69, 4.71, Solution Composition: #4.79, 4.85, 4.87, 4.90, 4.92, 4.110 Bonus Problems: 4.113, 4.115. eMedia Exercises: p. 164, # 4.118, 4.119, 4.120, 4.121. Student Guide: Review Chapter 4 and Take the Student Self Test. Note:*Personally select the MOST appropriate 25 problems based on your learning needs. Solution Stoichiometry and Chemical Analysis – Concept Questions In Chapter 4 your will study the different types of chemical reactions which take place in water solutions. As you study, focus on what is actually going on in a solution, what species are really present, and how they interact with each other. One full section of the AP Chemistry Exam is devoted to writing net ionic equations for basic chemical reactions. Set aside a section in your notes for the basic types of reactions. You will need to refer to these throughout the course and during your final review for the AP Exam. This chapter is descriptive, yet it includes a review of basic calculations which will be reinforced in later chapters. Concepts: 1. Describe the geometry of a water molecule. Why is the bond angle less than one would expect? 2. What does the term hydration mean? Explain the energy involved including the terms hydration energy and lattice energy. 3. Explain the strength of an electrolyte in both operational and conceptual terms. 4. Describe the purpose of the activities series. What indicator can you use to determine if it is set up in ease of oxidation or ease in reduction? (Note: A past AP Exam had the series in reverse order) 5. Complete the following table regarding the three types of reactions discussed in Chapter 4. Give one sample reaction for each. Type of Reaction Ways to recognize it? Basic Information-Memorize it! Write one example: Write one example: Write one example: 6. During a titration you sometimes see a color change before the end point is reached, why does this occur? What must you remember to be certain that the end point has been reached? What is the difference between an endpoint and an equivalence point? 7. HCl, HBr, HI are strong acids. Why does HF not follow this trend? 8. Why does NaOH need to be standardized? 9. How do you balance a redox equation in the "basic state"? 10. In water, why does the oxygen have more attraction for electrons than the hydrogen? Memorize: Strong Acids and Bases p.132; Solubility Rules/Tables p.127 and the Rules for Assigning Oxidation Numbers p. 139.