Chapter 4 Focus Questions 
Section 1 
1.	What is one of the most valuable properties of water? 
2.	What is a polar molecule and how would you represent it in a molecular model? 
3.	What is solubility and what properties should a compound have in order to have a high solubility in water? A low solubility in water? 
4.	What types of substances are most soluble in water? 
5.	Why can a nonionic substance such as alcohol be dissolved in water? 
6.	What types of substances cannot be dissolved by water? 

Section 2 
1.	Be sure to understand the terms solute, solvent, and solution. Be able to describe the difference between these terms. 
2.	What is an electrolyte? What is the difference between a strong, weak, or nonelectrolyte? 
3.	What relationship exists between acids and electrolytes? 
4.	Be sure to memorize all of the strong acids (see your “What I Need To Know” sheet). 
5.	What is the relationship between bases and electrolytes? 
6.	Be sure to memorize all of the strong bases 
7.	Why are weak acids and bases weak? What does this mean in terms of solubility and the dissolution of the original compound? 

Section 3 
1.	What is molarity (M)? How do you find this measurement? Be sure to know this! This is one of the most common measurements for solutions! 
2.	Look over the sample exercises 4.1 & 4.2 on pages 141-142. Do problem #15 on page 181. 
3.	Look over the sample exercises 4.3 & 4.4 on pages 142-143 on concentrations of ions. Do problem #17 on page 181. 

4.	What is a standard solution? 
5.	What is the process of preparing solutions by dilution (i.e., how would you do this)? 
6.	Look at sample exercises 4.5-4.7 on pages 143-146. Do problems # 23 and 25 on page 181. 

Section 4 
1.	What are the three broad classes of reactions that we can group individual
reactions in?

Section 5
1.	What is a precipitation reaction? What is a precipitate?
2.	What are two general rules that help us to identify the precipitate that is formed?
3.	Review the solubility rules that are outlined on page 152. You should have these memorized by now!
4.	What should you do before you try to figure out the chemistry of an aqueous solution?
5.	Be sure to review the sample exercise 4.8 on pages 153-154.

Section 6
1.	What is a molecular equation? What is a complete ionic equation? What is a net ionic equation?
2.	Review samples exercise 4.9 on page 155. Then do problem #35 on page 182.

Section 7
1.	What are the steps to solving stoichiometry problems for reactions in solutions?
2.	Review sample exercise 4.11 on page 157. Then do problems #39 and 41 on page 182.

Section 8
1.	What is the Brønsted-Lowry definition of an acid and a base?
2.	Why can hydrogen ion and hydroxide ion not exist in aqueous solutions in large amounts? What do they form?
3.	What is the difference between a net ionic equation for a strong acid or base and a weak acid or base? Make sure you have the strong acids and bases memorized!!!
4.	What are the steps for performing acid-base calculations?
5.	Read sample exercises 4.12 and 4.13 on pages 159-161. Now do problems #47 and 49 on page 183.
6.	What is volumetric analysis? What is a titration? What is a titrant? What is an analyte?
7.	What is the equivalence point or stoichiometric point? Of what use is an indicator? What is an indicator? What is the endpoint of the titration and what does it show us? What must you keep in mind when selecting an indicator for a titration?
8.	What are the three requirements for a successful titration?
9.	Be sure to read through sample exercises 4.14 and 4.15 on pages 162-163. Then do problem #55 on page183.
10.	What is the key to success in solving stoichiometric analysis of acid/base reactions?

Section 9
1.	What happens in an oxidation-reduction reaction? What is another name for this type of reaction?
2.	What is the charge on an atom? How do atoms become ions? 
3.	What is an oxidation state?
4.	Look at the rules for assigning oxidation states (table 4.2). You should be familiar with these rules and be able to use them to assign oxidation states to elements in compounds.
5.	Read sample exercise 4.16. Then do problem 57 on page 183.
6.	What is the oxidation state of iron in Fe3O4? How can this be possible?
7.	What is the definition of oxidation? What is the definition of reduction? What is an oxidizing agent? What does it do in a redox reaction? What is a reducing agent? What does it do in a redox reaction?
8.	Read sample exercises 4.17 and 4.18 on page 170-171. Then do problem 61 on page 183.

Section 10
1.	What is the half-reaction method and what is it used for?
2.	Read and understand the steps to the half reaction method for balancing redox reactions on page 172 and shown on pages 173-174. Be sure to know the steps involved! What do you do to balance the number of oxygens in a half-reaction? What do you do to balance the number of hydrogens?
3.	Read through sample exercise 4.19 on pages 175-176.
4.	What is different about redox reactions in basic solutions than in acidic solutions? What steps do you take that are different for the basic solutions than for the acidic solutions when balancing by the half-reaction method?
5.	Be sure to read through sample exercise 4.20 on pages 178-179.
6.	Do problems #63 and 65 on page 184.