1. Precipitation Reactions
Example: Write the complete balanced molecular equation for the reaction between aqueous solutions of sodium phosphate and calcium acetate. Write the complete ionic equation and the net ionic equation for the reaction.

2. Precipitation Reactions
Example: Write the equation for the reaction between NH4Cl (aq) and MgSO4 (aq).

3. Precipitation Reactions
If both products are soluble (aq), then NO REACTION is presumed to occur between the ionic compounds involved.
The reaction mixture simple contains a mixture of soluble ions.
NH4Cl (aq) + MgSO4 (aq)  No Reaction
On your exam, you should be able to indicate whether a reaction occurs or not.
If it occurs, write the formulas for the products
and balance.
If no reaction occurs, write the words, “No
Reaction.” (You should still show your work!)

4. Acids & Bases Acids: Arrhenius definition:
substances that ionize to form one or more hydrogen ions (H+) when dissolved in water
Bronsted-Lowry definition:
Proton (hydrogen ion) donor

5. Acids & Bases Examples of Acids: HCl hydrochloric acid
HNO3 nitric acid
HC2H3O2 acetic acid
H2SO4 sulfuric acid
H3PO4 phosphoric acid
Note: Acids can form different numbers of H+ ions when they ionize!

6. HNO3 (aq)  H+ (aq) + NO3- (aq)
Acids & Bases
Monoprotic acids
have one ionizable H in the formula (HA)
form a single H+ ion when they ionize
HNO3 (aq)  H+ (aq) + NO3- (aq)

7. H2SO4 (aq)  2H+ (aq) + SO42- (aq)
Acids & Bases
Diprotic acids
H2A
can form two H+ ion when they ionize completely
H2SO4 (aq)  2H+ (aq) + SO42- (aq)
Polyprotic acids:
Have two or more ionizable H’s in the formula
Form two or more H+ ions when they ionize completely

8. Acids & Bases Strong Acid: an acid that is a strong electrolyte
ionizes completely in solution
Weak Acid:
an acid that is a weak electrolyte
an acid that does not ionize completely

9. Acids & Bases Strong acids:
Know the names and formulas of the 7 common strong acids:
HCl (aq) hydrochloric acid
HBr (aq) hydrobromic acid
HI (aq) hydroiodic acid
HClO3 chloric acid
HClO4 perchloric acid
HNO3 nitric acid
H2SO4 sulfuric acid

10. Acids & Bases Examples of Weak Acids HF (aq) hydrofluoric acid
H3PO4 phosphoric acid
HC2H3O2 acetic acid

11. Acids & Bases Bases: substances that accept (react with) H+ ions.
any substance that increases the OH- concentration when added to water
Examples:
NaOH (aq)  Na+ (aq) + OH- (aq)
Ca(OH)2 (aq)  Ca2+ (aq) + 2 OH- (aq)

12. NH3(aq) + H2O (l) NH4+ (aq) + OH- (aq) NH3 is a weak electrolyte!!
Acids & Bases
Examples of Bases (cont):
Ammonia (NH3)
Does not contain OH-
Accepts H+ ion from water and increases the OH- concentration in the water
NH3(aq) + H2O (l) NH4+ (aq) + OH- (aq)
NH3 is a weak electrolyte!!

13. Acids & Bases Strong Base: a base that is a strong electrolyte
ionizes completely in solution
Weak Base:
a base that is a weak electrolyte
does not ionize completely in solution

14. Acids & Bases
Strong Bases: Know the names and formulas of the strong bases
Alkali metal (1A) hydroxides
LiOH lithium hydroxide
NaOH sodium hydroxide
KOH potassium hydroxide
RbOH rubidium hydroxide
CsOH cesium hydroxide

15. Acids & Bases Strong bases to know (con’t):
Heavy alkaline earth metal (2A) hydroxides
Ca(OH)2 calcium hydroxide
Sr(OH)2 strontium hydroxide
Ba(OH)2 barium hydroxide

16. Acids & Bases Examples of Weak Bases: ammonia (NH3)
sodium bicarbonate (NaHCO3)
baking soda
a component of Alka-Seltzer

17. HCl (aq) + NaOH (aq)  H2O (l) + NaCl (aq)
Acid-Base Reactions
Reactions between acids and bases are called neutralization reactions.
HCl (aq) + NaOH (aq)  H2O (l) + NaCl (aq)
Salt:
any ionic compound whose cation comes from a base and whose anion comes from an acid
An ionic compound that is neither an acid nor a base
salt

18. Acid-Base Reactions
In general the equation for the neutralization of any acid by a metal hydroxide is:
acid + metal hydroxide  a salt + water
2 HC2H3O2 (aq) + Ca(OH)2  Ca(C2H3O2)2 (aq) + 2 H2O (l)
H3PO4 (aq) + 3 KOH (aq)  K3PO4 (aq) + 3 H2O (l)
Neutralization reactions are a type of metathesis reaction.

19. Acid-Base Reactions
To predict the products of a neutralization reaction:
identify the ions present
exchange anions
write the correct formulas for the products including physical states
write a balanced equation

20. Acid-Base Reactions
Example: Write the balanced equation for the reaction between aqueous solutions of HBr and Ca(OH)2.

21. Acid-Base Reactions
You can also write complete and net ionic equations for acid-base reactions:
Molecular equation:
2HBr (aq) + Ca(OH)2 (aq)  CaBr2 (aq) + 2H2O (l)
Complete ionic equation:
2 H+ (aq) + 2Br- (aq) + Ca2+ (aq) + 2 OH- (aq)  Ca2+ (aq)
+ 2 Br- (aq) + 2 H20 (l)

22. H+ (aq) + OH- (aq)  H2O (l)
Acid-Base Reactions
Complete ionic equation:
2 H+ (aq) + 2Br- (aq) + Ca2+ (aq) + 2 OH- (aq) 
Ca2+ (aq) + 2 Br- (aq) + 2 H20 (l)
Net ionic equation:
H+ (aq) + OH- (aq)  H2O (l)
Note: This is the net ionic equation between any strong acid and strong base.

23. Acid-Base Reactions
Example: Write the balanced molecular equation for the reaction between Mg(OH)2 (s) and HCl (aq). Write the complete ionic and net ionic equations.

24. Acid-Base Reactions
Example: Write the balanced molecular equation for the reaction between aqueous solutions of sodium hydroxide and phosphoric acid. Write the complete ionic and net ionic equations.

25. Acid-Base Reactions There are many bases that do not contain OH- Na2S
NaCN
Na2CO3
NaHCO3
These bases react with acids to form gaseous products instead of water.

26. Acid-Base Reactions Examples: KCN (aq) + HCl (aq)  HCN (g) + KCl (aq)
HBr (aq) + NaHCO3 (aq)  NaBr (aq) + H2CO3 (aq)
but:
H2CO3 (aq)  H2O (l) + CO2 (g)
so:
HBr (aq) + NaHCO3 (aq)  NaBr (aq) + H2O (l) + CO2 (g)

27. Acid-Base Reactions
You should remember the following physical states/reactions for the exam.
H2S (g)
HCN (g)
H2CO3 (aq)  H2O (l) + CO2 (g)