The document discusses different types of chemical reactions including acid-base reactions where an acid and base react to form a salt and water, precipitation reactions where insoluble compounds form solid precipitates, and oxidation-reduction reactions where electrons are lost or gained. Examples of each type of reaction are provided and rules for determining oxidation states and predicting products are explained.

1. ACID-BASE
PRECIPITATION
AND OXIDATION-
REDUCTION REACTIONS

2. LAW OF CONSERVATION
OF MASS
What you put in, you have to get out.
• Mass of reactants = mass of products
• Demo: Steel wool and balloon
• Fe(s) + O2 → Fe2O3
What is the easiest way for you to remember the law of
conservation of mass?

3. __Fe(s) + __O2 → __Fe2O3
24 3 2
4 2 1 Fe 2 4
6 2 O 3 6

4. ON YOUR WHITE BOARDS:
Write and balance the reaction
between zinc and oxygen

5. 2Zn(s) + O2(g)  2ZnO(s)

6. ON YOUR WHITE BOARDS:
Write the reaction between zinc oxide and nickel
Remember, what do you need to check when you write single replacement reactions?

7. ANSWER
ZnO + Ni  No Reaction
Zinc is more active than nickel on the Activity
Series, so nickel cannot replace zinc in the reaction.

8. ACID-BASE REACTIONS
 How can you tell if a compound is an acid?
• The compound begins with hydrogen ( has H+)
 How can you tell if a compound is a base?
• The compound has the polyatomic ion hydroxide (has OH - )
 How to identify an acid-base reaction:
Acid + Base → Salt + Water

9. ACID-BASE EXAMPLE
 HCl + Mg(OH)2 → MgCl2 + H2O
Acid because Base because Salt because ionic (metal and
hydrogen HCl is nonmetal)
hydroxide Mg(OH)2 is milk of
stomach acid magnesia which is an
antacid (neutralizes the
stomach acid)

10. PRECIPITATE REACTIONS
 Precipitate = insoluble
• Determine using solubility chart
 Is a precipitate considered soluble or insoluble?
 Where would you look to see if a precipitate will be formed?
• The solubility chart in your reference materials

12. Would NH4OH be soluble or insoluble?
1. Find the anion on the chart
2. Is the anion in the soluble or insoluble
box? Insoluble
3. Is the anion with any of the
exceptions? Yes
4. Is it soluble or insoluble?

13. OXIDATION REDUCTION
REACTIONS
 Oxidation– loss of electrons
 Reduction- gain of electrons
 In the following video, watch for what is being oxidized, what is
being reduced. How can you tell the difference?
 http://highered.mcgraw-
hill.com/olcweb/cgi/pluginpop.cgi?it=swf::100%::100%::/sites/dl/free/0072512644/117354/06_Oxidation_Re
duxn_Rxns.swf::Oxidation%20Reduction%20Reactions

14. LEO GOES GER
Lose Gain
Electrons goes Electrons
Oxidation Reduction

15. Rules:
• Track electrons by assigning oxidation numbers (charge)
• For atoms in their elemental form, the oxidation number is 0
• For ions, the oxidation number is equal to their charge
• For single hydrogen, the number is usually +1
• For oxygen, the number is usually -2
• The sum of the oxidation number of all the atoms in the molecule
or ion is equal to its total charge

16. PRACTICE
On your white boards, assign the oxidation
number for the following:
• Cu 0
• FeCl3 3+
• H2SO4 6+

17. PRACTICE
Predict the products and balance:
• C2H5OH + O2
Answer:
2 C2H5OH + 7O2 → 4CO2 + 6H2O

18. PRACTICE
 Calculate the mass of oxygen used in the demo reaction.

19. PRACTICE
Complete, balance, and identify:
• H2SO4 + Ca(OH)2 →
• Li2S + Cu →
• PbBr2 + Li2SO4 →
• K + O2 →

20. PRACTICE ANSWERS
Complete, balance, and identify:
• H2SO4 + Ca(OH)2 → CaSO4 + 2H2O Acid - Base
• Li2S + Cu → No Reaction Oxidation - Reduction
• PbBr2 + Li2SO4 → PbSO4 + 2LiBr Precipitation
• K + O2 → K2O Oxidation - Reduction

21. PRE-LAB:
 Determine the products and balance the equation for each reaction
and predict what type of reaction (acid-base, precipitate, or oxidation
- reduction) will occur.
 Al(s) + CuCl2(aq) →
 KI(aq) + AgNO3(aq) →
 NaOH(aq) + HC2H3O2(aq) →

22. POST - LAB
2Al(s) + 3CuCl2(aq) → 3Cu(s) + 2AlCl3(aq)
Oxidation - Reduction
KI(aq) + AgNO3(aq) → KNO3(aq) + AgI(s)
Precipitation
NaOH(aq) + HC2H3O2(aq) → NaC2H3O2(aq) + H2O(l)
Acid - Base