1. Chapter 4 Reactions in Aqueous Solution
Chemistry: McMurry and Fay, 6th Edition
Chapter 4: Reactions in Aqueous Solution
5/19/2019 3:55:57 AM
Chapter 4 Reactions in Aqueous Solution
Copyright © 2011 Pearson Prentice Hall, Inc.

2. Naming Chemical Compounds
Chapter 2: Atoms, Molecules, and Ions
5/19/2019
Naming Chemical Compounds
Binary Acids
HCl hydrochloric acid
HBr hydrobromic acid
HF hydrofluoric acid
Copyright © 2008 Pearson Prentice Hall, Inc.

3. Naming Chemical Compounds
Chapter 2: Atoms, Molecules, and Ions
Naming Chemical Compounds
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Oxoacids do not begin with “hydro.”
Hydrochloric acid: HCl
Chloric acid: HClO3
“ous”
“ite”
“ic”
“ate”
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4. Examples
Name the following acids HI
HCN
HNO3
H3PO4
H3PO3

5. Some Ways That Chemical Reactions Occur
Chapter 4: Reactions in Aqueous Solution
5/19/2019
Some Ways That Chemical Reactions Occur
Precipitation Reactions: Processes in which soluble reactants yield an insoluble solid product that falls out of solution.
2KNO3(aq) + PbI2(s)
Pb(NO3)2(aq) + 2KI(aq)
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6. Some Ways That Chemical Reactions Occur
Acid-Base Neutralization Reactions: Processes in which an acid reacts with a base to yield water plus a salt.
H2O(l) + NaCl(aq)
HCl(aq) + NaOH(aq)
Acid Base  Water + Salt

7. Some Ways That Chemical Reactions Occur
Chapter 4: Reactions in Aqueous Solution
5/19/2019
Some Ways That Chemical Reactions Occur
Oxidation-Reduction (Redox) Reactions: Processes in which one or more electrons are transferred between reaction partners (atoms, molecules, or ions).
MgCl2(aq) + H2(g)
Mg(s) + 2HCl(aq)
Element + Compound  Compound + Element
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8. Electrolytes

9. Electrolytes in Aqueous Solution
Chapter 4: Reactions in Aqueous Solution
Electrolytes in Aqueous Solution
5/19/2019
Strong Electrolytes: Compounds that dissociate to a large extent into ions when dissolved in water.
KCl(aq)
K1+(aq) + Cl1-(aq)
Weak Electrolytes: Compounds that dissociate to a small extent into ions when dissolved in water.
H1+(aq) + CH3CO21-(aq)
CH3CO2H(aq)
For a 0.10 M solution, KCl is approximately 98% dissociated while CH3CO2H (acetic acid) is a little more than 1% dissociated.
The size of the arrows indicate which side of the chemical equation the equilibrium lies on.
The use of the equilibrium arrows is minimal until later chapters on kinetics and chemical equilibrium.
Nonelectrolytes: Substances which do not produce ions in aqueous solutions.
H2O
C12H22O11(aq)
C12H22O11(s)
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10. Electrolytes in Aqueous Solution
Chapter 4: Reactions in Aqueous Solution
5/19/2019
Electrolytes in Aqueous Solution
Strong acids are strong electrolytes (which is why they are called strong acids!). These are typically called the 6 common strong acids. There are other strong acids.
Strong Acids: hydrochloric acid, hydrobromic acid, hydroiodic acid, perchloric acid, nitric acid, sulfuric acid.
Copyright © 2008 Pearson Prentice Hall, Inc.

11. Electrolytes in Aqueous Solution
Chapter 4: Reactions in Aqueous Solution
5/19/2019
Electrolytes in Aqueous Solution
Hydroxides are also ionic compounds.
Ionic Compounds
Copyright © 2008 Pearson Prentice Hall, Inc.

12. Electrolytes in Aqueous Solution
Chapter 4: Reactions in Aqueous Solution
5/19/2019
Electrolytes in Aqueous Solution
Any acid that’s not a strong acid is considered to be a weak acid.
Weak acids
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13. Electrolytes in Aqueous Solution
Chapter 4: Reactions in Aqueous Solution
5/19/2019
Electrolytes in Aqueous Solution
Any molecular compounds which are not already classified (acids are molecular).
While water does dissociate to a small degree, we consider it to be a nonelectrolyte. The dissociation of water will be dealt with in a later chapter.
Molecular Compounds
(other than any strong or weak electrolytes)
Copyright © 2008 Pearson Prentice Hall, Inc.

14. Aqueous Reactions and Net Ionic Equations
Chapter 4: Reactions in Aqueous Solution
5/19/2019
Aqueous Reactions and Net Ionic Equations
Molecular Equation: All substances in the chemical equation are written using their complete formulas as if they were molecules.
2KNO3(aq) + PbI2(s)
Pb(NO3)2(aq) + 2KI(aq)
strong electrolytes
indicated as (aq)
soluble
Precipitate
insoluble
Granted, all of the substances in the chemical equation are ionic compounds but it’s common to call this the molecular equation.
Pictures are useful especially with this reaction. Solutions of lead(II) nitrate and potassium iodide are colorless while the precipitate of lead(II) iodide is yellow.
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15. Aqueous Reactions and Net Ionic Equations
Chapter 4: Reactions in Aqueous Solution
5/19/2019
Aqueous Reactions and Net Ionic Equations
Ionic Equation: All of the strong electrolytes are written as ions.
Pb(NO3)2(aq)
2KI(aq)
Pb2+(aq) + 2NO31- (aq) + 2K1+(aq) + 2I1-(aq)
2K1+(aq) + 2NO31- (aq) + PbI2(s)
Note the proper charges (as learned previously when writing ionic compound formulas).
2KNO3(aq)
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16. Aqueous Reactions and Net Ionic Equations
Chapter 4: Reactions in Aqueous Solution
5/19/2019
Aqueous Reactions and Net Ionic Equations
Spectator Ions: Ions that undergo no change during the reaction and appear on both sides of the reaction arrow.
Pb2+(aq) + 2NO31- (aq) + 2K1+(aq) + 2I1-(aq)
2K1+(aq) + 2NO31- (aq) + PbI2(s)
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17. Aqueous Reactions and Net Ionic Equations
Chapter 4: Reactions in Aqueous Solution
5/19/2019
Aqueous Reactions and Net Ionic Equations
Net Ionic Equation: Only the ions undergoing change are shown.
PbI2(s)
Pb2+(aq) + 2I1-(aq)
This doesn’t suggest that you can actually have a solution of iodide ion. The corresponding cations and anions are present but they are spectator ions.
An aqueous solution that contains lead(II) ion when mixed with another one that contains iodide ion will typically produce a precipitate of lead(II) iodide.
Copyright © 2008 Pearson Prentice Hall, Inc.
Copyright © 2008 Pearson Prentice Hall, Inc.

18. Precipitation Reactions and Solubility Guidelines
Chemistry: McMurry and Fay, 6th Edition
Chapter 4: Reactions in Aqueous Solution
5/19/2019 3:55:57 AM
Precipitation Reactions and Solubility Guidelines
Copyright © 2011 Pearson Prentice Hall, Inc.

19. Precipitation Reactions and Solubility Guidelines
Chapter 4: Reactions in Aqueous Solution
5/19/2019
Precipitation Reactions and Solubility Guidelines
Write the molecular, ionic, and net ionic equations for the reaction that occurs when aqueous solutions of AgNO3 and Na2CO3 are mixed.
Swap the cations to determine the possible products.
Properly written products! Not: AgCO3 and Na2NO3.
Copyright © 2008 Pearson Prentice Hall, Inc.

20. Precipitation Reactions and Solubility Guidelines
Write the chemical formulas of the products (use proper ionic rules).
AgNO3(aq) +
Na2CO3(aq)
Ag2CO3(??) +
NaNO3 (??)
CB + AD
AB + CD
double replacement reaction

21. Example
Write the molecular, ionic, and net ionic equations for the reaction that occurs when
aqueous solutions of FeCl3 and Na2SO4 are mixed
Aqueous solution of Mg(NO3)2 and NH4OH