Exam 3 Study Guide - General Chemistry | CHEM 201, Exams of Chemistry

Download Exam 3 Study Guide - General Chemistry | CHEM 201 and more Exams Chemistry in PDF only on Docsity! Chem 201 Fall 2009 EXAM 3 STUDY GUIDE The exam will consist of 20 multiple choice questions with 70% “C” questions, 20% “B” questions, and 10% “A” questions. In general, “C” questions are those involving the most basic concepts, particularly ones that you have used before. “C” calculation problems typically involve one major step with 1-2 more 3minor steps. (Examples of minor steps would be calculating molecular weights or converting [H O ] to + pH.) “B” questions involve more difficult concepts, particularly ones that are new. “B” calculation questions typically involve at least two major steps with 1-4 minor steps. “A” questions are those involving the most difficult concepts or those that require a thorough understanding in order to answer correctly. Often “A” questions require bringing together different concepts to solve the problem and 2+ calculation steps. Note also that concepts listed under the “C” or “B” categories below can be converted to harder questions, depending on how I ask the question. Background Concepts [Homework Examples; similar questions in italic that weren’t previously assigned] • Calculate molar mass, convert between grams and moles using the molar mass. [3.8, 3.12, 3.23, 3.63] • Calculate concentrations in molarity, convert between liters and moles using molarity. [3.94, 3.96, 3.100] • Know the names, molecular formulas and charges of common ions. [Ions in bold in Tables 2.3, 2.4, 2.5] “C” Questions [Homework Examples] Chapter 20: f f• Know how to calculate ÄG° from ÄG ° values, or ÄH ° and ÄS° values. [20.50, 20.52, Quiz 7] • Understand the difference between ÄG and ÄG°. Understand the relationship between ÄG and spontaneous change. Be able to interpret free energy diagrams like those in Figure 20.15. • Predict whether K>1 or <1 from ÄG°. • Calculate K from ÄG°, and ÄG° from K. [20.68, 20.76, 78a, quiz 7] Chapter 21: • Know what "oxidation" and "reduction" mean. [21.1] • Determine oxidation numbers; decide what is being oxidized and what is being reduced; identify oxidizing and reducing agents. [21.10, quiz 7] • Balance oxidation-reduction reactions in acidic or basic solution. [21.12, 21.18, quiz 7] • Understand the basics of how an electrochemical cell works. [21.27] • Know what "electrode", "anode" and "cathode" mean. • Understand the shorthand notation for electrochemical cells. [21.33, 21.34, quiz 7 and 8] • Be able to determine the overall reaction occurring in a given electrochemical cell and visa versa: construct an electrochemical cell in which a given oxidation reduction reaction will occur. [21.33, 21.34, quiz 8] cell• Calculate E° from E° values. [additional problem 1, 21.42, quiz 8] cell• Calculate ÄGE from E° and vice versa. [21.64, 21.60, quiz 8] Chapter 16: • Know the relationship between reaction rates for different reaction components. [16.14, 16.22, quiz 9] • Know what the rate law, reaction order and rate constant are.[16.23, 16.26, 16.30, quiz 9]