CH 221 Chapter Guides

Chapter Guide Four: Overview | Resources | Practice

  Overview of Chapter Guide Four

This module has several key components. The first portion explores the important chemical concepts of stoichiometry, limiting reactant, reactants in excess, percent yield, and chemical analysis. The second portion explores the concepts of solubility, types of reactions and net ionic reactions.

Chapter 4 Part I introduces us to the important concept of stoichiometry, or knowing how much of each reactant we need to start a reaction. We will learn about balancing equations and master its techniques. We will then explore the relationship between a limiting reactant and a "reactant in excess". We can use stoichiometry and the limiting reactant idea to find theoretical yields and percent yields from equations. Finally, we will use these ideas to understand chemical analysis, or knowing how to find a molecular formula using the molar mass and the empirical formula.

For a complete list of important concepts in Chapter 4 Part I, see the Chapter 4 Part I Study Guide.

Chapter 4 Part II introduces us to solubility, or knowing if a certain compound will dissolve in solution. We will use water as our solvent in this section, and we will explore solubility in greater detail in CH 223. Exploring net ionic reactions (and knowing how they differ from regular molecular reactions) will be our next task, for the net ionic equation allows us to see the "action" in a particular reaction. We will also begin to study the different types of reaction which guide chemists through new sets of chemical combinations (we shall continue this exploration in Module 5.)

For a complete list of important concepts in Chapter 4, see the Chapter 4 Part II Study Guide.

  Resources for Chapter Guide Four

For this module, you should read Chapter 4 in your textbook.

The following screencasts might prove useful to you as you study this chapter.

The Chapter Four Part I Lecture notes and Chapter Four Part II Lecture notes which accompany this lesson will be helpful to you when going through this section. These are Web versions of the notes I use in my "normal" CH 221 class and should let you see what is important to me in this chapter.

A variety of handouts are available from Chapter Four Part I. Feel free to explore all of them or just the ones which give you difficulty.

Once you have mastered the concepts listed above, check out the Chapter Four Part I Concept Guide and the Chapter Four Part II Concept Guide for a series of worked problems relating to this chapter. They will help you to ensure the mastery of the knowledge from this chapter.

Finally, test yourself (and get extra-credit in the bargain!) on the following chemistry concepts. If you get 9 out of 10 correct (or some multiple thereof), submit the information to me to receive extra credit.

  1. Balancing Chemical Reactions
  2. Basic Stoichiometry - Grams to Moles
  3. Basic Stoichiometry - Moles to Moles
  4. Basic Stoichiometry - Grams to Grams
  5. Limiting Reagents
  6. Using Limiting Reagents
  7. Calculations Based on Percent Yields
  8. Combining Limiting Reagent and % Yield
  9. Combustion Analysis

  Practice the Concepts of Chapter Guide Four

Please complete problem set #4 to further explore the molecule and compound concepts. Problem set #4 covers several questions from Chapter 4 Part 1, and it can be found here. We will discuss problems like these during recitation, so come prepared to ask and answer questions.

For additional practice, try completing practice problem set #4 (with answers included at the end) and/or the non-assigned problems in Chapter 4. Answers to many of those problems are listed in the back of your textbook.

If you need assistance on these problems, you have several options. You can visit the AVID / Learning Success Center located above the MHCC library on the Mt. Hood Community College campus; they have tutors available to help you with your chemistry homework. You can also contact me if you have any questions.

Test your mastery of the subject matter by trying the self quiz for Chapter 4. This is an ungraded test that you can use to gauge your comfort level with these concepts. This sample Quiz #4 (answers) (which was given during a previous year's CH 221 class) will help you understand the kind of questions that will be asked on the quiz

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