1. Drill #4B /10/15
Predict the products and balance the equation for the following double-replacement reaction:
Na2CrO4 (aq) + Ba(OH)2 (aq) →

2. Drill # /10/15
Translate and predict products for the following reactants:
calcium hydroxide + phosphoric acid
FeCl3 + NH4OH

3. Answer 1 Na2CrO4 (aq) + 1 Ba(OH)2 (aq) → 2 NaOH (aq) + 1 BaCrO4 (s)
BaCrO4 is the precipitate (solid) – how do we know this? Solubility Rules

4. Agenda
Pass fwd 9-2 Practice Problems.

5. Drill # 4A 2/9/15
Write the balanced chemical equations for the following:
aluminum bromide + chlorine yield aluminum chloride + bromine
Potassium chlorate when heated yields potassium chloride + oxygen gas
Hydrogen + nitrogen monoxide yield water + nitrogen

6. Agenda Predicting Products
Precipitation Reactions and Solubility Rules
Lab on Wed

7. Predicting Products of Reactions

8. Synthesis Reactions: A + B  AB
Element + Element  Compound
There are other forms, but for your test, it will always be an ionic compound
To predict the products of a synthesis reaction, just cross the charges of the elements
Example:
Li + Br2  ?
Li + Br2  LiBr
2Li + Br2  2LiBr (balanced)

9. Synthesis Practice Mg + N2  ? Mg + N2  Mg3N2 3Mg + N2  Mg3N2
Mn + Cl2  ? (Use Mn2+)
Mn + Cl2  MnCl2 (already balanced)
K + O2  ?
K + O2  K2O
4K + O2  2K2O

10. Decomposition Reactions AB  A + B
Compound  Element + Element
There are other forms, but for your test, we will always end with two elements.
To predict the product, just separate the compound into elements.
Example:
CaO  ?
CaO  Ca + O2
2 CaO  2 Ca + O2
DON’T FORGET THE
DIATOMIC ELEMENTS!
H2, N2, O2, F2, Cl2, Br2, I2

11. Decomposition Practice
PbI2  ?
PbI2  Pb + I2 (already balanced)
NH3  ?
NH3  N2 + H2
2 NH3  N2 + 3 H2
Li2S  ?
Li2S  Li + S
Li2S  2 Li + S
AlF3  ?
AlF3  Al + F2
2AlF3  2Al + 3F2

12. Single Replacement Reactions
Element + Compound  New Element + New Compound
2 forms:
A + BC  AC + B (A is a metal) OR
X + YZ  YX + Z (X is a nonmetal)

13. Single Replacement Rxns. Cont.
You must use an Activity Series to determine if there is a reaction.
If the free metal is above the bonded metal on the Metal Activity Series (on the back of your Periodic Table), the free metal will take the place of the bonded metal. (If it is below, then NR – no reaction)
If the free nonmetal is above the bonded nonmetal on the Periodic Table, the free nonmetal will take the place of the bonded nonmetal. (If it is below, then NR.)

14. Single Replacement Practice
Fe + CuSO4  ? (use Fe2+)
Fe + CuSO4  FeSO4 + Cu (already balanced)
Why? Fe is above Cu on the Activity Series
Ca + HgO  ?
Ca + HgO  CaO + Hg (already balanced)
Why? Ca is above Hg on the Activity Series

15. Single Replacement Practice
Ni + Mn2O3  ? (Use Ni2+)
Ni + Mn2O3  NR (no need to balance!)
Why? Ni is below Mn on the Activity Series
Al + FeCl2  ?
Al + FeCl2  Fe + AlCl3
Why? Al is above Fe on the Activity Series
2 Al + 3 FeCl2  3 Fe + 2 AlCl3

16. Single Replacement Practice
MnCl3 + F2  ?
MnCl3 + F2  MnF3 + Cl2
Why? F is above Cl on the Periodic Table
2 MnCl3 + 3 F2  2 MnF3 + 3 Cl2
S + Na2O  ?
S + Na2O  NR (no need to balance!)
Why? S is below O on the Periodic Table

17. Double Replacement Reactions AB + CD  AD + CB
Compound + Compound  New Compound + New Compound
To predict, swap ion pairs and re-cross charges.
Example:
Fe(OH)2 + H2SO4  ?
Fe(OH)2 + H2SO4  FeSO4 + HOH (H2O)
Fe(OH)2 + H2SO4  FeSO4 + 2 H2O

18. Double Replacement Practice
KI + PbCl2  ?
KI + PbCl2  KCl + PbI2
2 KI + PbCl2  2 KCl + PbI2

19. Combustion Reactions CxHx + O2  CO2 + H2O
Any reaction between a compound of carbon and hydrogen (CxHx) and oxygen will produce the same two products – carbon dioxide and water!
Example:
CH4 + O2  ?
CH4 + O2  CO2 + H2O
CH4 + 2 O2  CO2 + 2 H2O

20. Combustion Practice C6H6 + O2  ? C6H6 + O2  CO2 + H2O
C2H5OH + O2  ?
C2H5OH + O2  CO2 + H2O
C2H5OH + 3 O2  2 CO2 + 3 H2O

21. Precipitation Reactions
No ionic compound is entirely insoluble in water, however compounds of low solubility can be considered insoluble for most practical purposes.
There are some general guidelines to help predict whether a compound made of a certain combination of ions is soluble.

22. Solubility Rules Table
Use this table to determine if precipitation will occur.
Precipitation occurs when the attraction between the ions is greater than the attraction between the ions and surrounding water molecules.
Precipitate = solid

23. Assignment
Complete the “Double Replacement Reactions and the Solubility Rules” worksheet
Directions: use the solubility rules handout to determine the correct phase for each product
Review WS