1. Chapter 20 Predicting the Products of a Chemical Reaction
Chapter 11 TYPES OF CHEMICAL REACTIONS
Chapter 20 Predicting the Products of a Chemical Reaction

3. I can ……. double replacement Precipitation Acid / base
classify reactions:
double replacement
Precipitation
Acid / base
predict and write the products of the above types of reactions.
predict the states of the reactants by using the solubility rules.
identity spectator ions and explain what they do.

4. Double Replacement Reactions
Reactants are always 2 compounds
Products are always 2 new compounds
The same charge ions switch partners

5. We do not just “switch” the cations (metals) to create the products.
NaCl + BaO → NaO + BaCl is not correct !!
You must make sure you follow the rules of formula writing when writing new compounds:
Predict what is formed in the reaction
Check the charges of each ion
Criss-cross and drop charges to write correct chemical formulas
Balance the final equation using coefficients

6. Examples:. 1. Predict what is formed in the reaction. 2
Examples: 1. Predict what is formed in the reaction 2. Check the charges of each ion 3. Criss-cross and drop Write correct formula 5. Balance the final equation MgCl CaS  MgS + CaCl Be(NO3) K2SO4  2KNO3 + BeSO4

7. Beautiful Chemical Reactions
Specific Types of Double Replacement Reactions Precipitation – two aqueous solutions react to form one solid precipitate and an aqueous solution Example: KCl(aq) + AgNO3(aq)  KNO3 (aq) + AgCl (s)
Beautiful Chemical Reactions

8. Specific Types of Double Replacement Reactions Acid/Base “Neutralization – An acid (always starts with “H”) and a base (always ends in “OH”) react to form a salt and water Example: HCl(aq) + NaOH(aq)  NaCl(aq) + H2O(l)

9. Acid – Base Neutralization Reactions (write these reactions)
Acid + Base  Salt + Water HCl + NaOH  NaCl + H2O
HNO3 + KOH  KNO3
+ H2O
Copy

10. Double Replacement – Precipitation Reactions Soluble – able to be dissolved in water (aq) Insoluble – not able to be dissolved in water (s)
Na+ and Cl- are called SPECTATOR IONS.
They do not react and remain dissolved in solution
Solid precipitate

11. Double Replacement – Precipitation Reactions
Ionic compounds that dissolve in water split apart into ions. Ions conduct electricity when dissolved in solution. Electrolytes are any ionic compounds which are soluble and thus conduct electricity
Ionic compounds that do not dissolve are insoluble and are called precipitates. These compounds form a solid when in solution

12. Double Replacement – Precipitation Reactions
Solubility was discovered by trial and error. Over time, scientists developed a set of rules (solubility rules) which help predict the solubility of a substance
When new compounds are formed in a double replacement reaction, you must identify the solubility (state) of the products
Soluble = (aq)
Insoluble = (s) - precipitate

13. Double Replacement – Solubility Rules
SOLUBILITY RULES FOR COMMON IONIC COMPOUNDS IN WATER
Mainly water soluble
NO­3- All nitrates are soluble
C2H3O2- All acetates are soluble
ClO3- All chlorates are soluble
Cl- All chlorides are soluble EXCEPT AgCl, Hg2Cl2, and PbCl­2
Br- All bromides are soluble EXCEPT AgBr, Hg2Br2, and HgBr­2
I- All iodides are soluble EXCEPT AgI, Hg2I2, and HgI­2
SO42- All sulfates are soluble EXCEPT CaSO4, SrSO4, BaSO4, PbSO4, Hg2SO4, and Ag2SO4
Mainly water insoluble
S2- All sulfides are insoluble EXCEPT those of groups 1 & 2 and (NH4)2S
CO32- All carbonates are insoluble EXCEPT those of group 1 and (NH4)2CO3
CrO42- All chromates are insoluble EXCEPT those of group 1 and (NH4)2CrO4
PO43- All phosphates are insoluble EXCEPT those of group 1 and (NH4)3PO4
OH- All hydroxides are insoluble EXCEPT those of group 1, Ba(OH)2, Sr(OH)2, and Ca(OH)2
Double Replacement – Solubility Rules

14. Double Replacement Reactions

15. Draw a picture of each solution showing the ions present
Consider 2 Beakers: One with aqueous silver nitrate, one with aqueous barium chloride
Draw a picture of each solution showing the ions present
Ba 2+
Ag1+
Cl 1-
NO31-
Cl 1-

16. Consider 2 Beakers: One with aqueous silver nitrate, one with aqueous barium chloride
Draw a picture after the solutions are mixed (before new compounds are formed
Ag1+
NO31-
Ba 2+
Cl 1-
Cl 1-

17. Consider 2 Beakers: One with aqueous silver nitrate, one with aqueous barium chloride
Predict the products for any reaction that occurs and draw what would be in the beaker (check solubility rules)
Write an equation for the reaction:
2AgNO3 (aq) + BaCl2 (aq) 
2AgNO3 (aq) + BaCl2 (aq)  2AgCl (s) + Ba(NO3) 2 (aq)

18. Consider 2 Beakers: One with aqueous silver nitrate, one with aqueous barium chloride
Spectator Ions – Ions that remain as ions on both sides
of the equation (do not become part of a precipitate)
List the spectator ions in this example:
NO31-
Ba 2+

19. Double Replacement – Precipitation Reactions
Use the solubility rules to predict what will happen when the following solutions are mixed. Label each new compound with an (aq) (electrolyte) or (s) (precipitate). Circle the ions that would be spectator ions
2KNO3 + BaCl2
Na2SO4 + Pb(NO3)2
Na2S + Cu(NO3)2
2NH4Cl + Pb(NO3)2
swap front ions
Criss-cross charges
balance equations
 Ba(NO3)2 (aq) + 2KCl (aq)
 2 NaNO3 (aq) + PbSO4 (s)
 2 NaNO3 (aq) + CuS (s)
 2 NH4NO3 (aq) + PbCl2 (s)

20. Chapter I can …….
Identify oxidation – reduction reactions which are also called Redox reactions
Predict products for redox reactions

21. Oxidation Reduction Reactions (Synthesis, Decomposition, Single Replacement, Combustion)
In these reactions, electrons are transferred from one atom to another
Atoms that lose electrons (become more positive) are oxidized
Atoms that gain electrons (become more negative) are reduced
LEO says GER or OIL RIG
Lose Electron Oxidized Oxidation Is Loss
Gain Electrons Reduced Reduction Is Gain

22. How to determine if element gains or loses electrons from its charge
e- carry negative charge! Remember this!
Element loses e-
Element “-” so element becomes more positive
= 0 +1
Element gains e-
Element “+” so element becomes more negative
= 0 - 1

23. Oxidation Reduction Reactions
Example 1: Identify the element that has been oxidized and the element that has been reduced.
2Ca O2  2CaO
Step 1: Write the charge above any ions that are part of a compound
Step 2: Write a zero above any elements that exist by themselves (or as a diatomic)
Step 3: Label atoms that have gained electrons (become more negative) as reduced, and label atoms that have lost electrons (become more positive) as oxidized 2+ 2-
Ca became more positive
So Ca lost electrons
so it was oxidized
Oxygen became more negative
So O gained electron
so it was reduced

24. Oxidation Reduction Reactions
Example 2: Identify the element that has been oxidized and the element that has been reduced.
Zn HCl  ZnCl H2 1+ 1- 2+ 1-
Zn became more positive
So Zn lost electrons
so Zn was oxidized
H became more negative
So H gained electrons
so H was reduced

25. Predicting Products of ReDox Reactions
Synthesis – More than one reactant, but a single product
Example:
2Mg O2  2MgO
Decomposition – A single reactant, multiple products
2KNO3  KNO O2

26. Predicting Products of ReDox Reactions
Combustion – Reactants are always a hydrocarbon and oxygen, products are always CO2 (carbon dioxide) and H2O (water)
Examples of hydrocarbons (must have C and H):
CH4
C2H6
CH2O
C6H12O6
Example: CH O2  CO H2O

27. One element replaces another element in a compound
SINGLE REPLACEMENT:
One element replaces another element in a compound
element + compound =
new element + new compound
A + BC  B + AC

28. Predicting Products of ReDox Reactions
Single Replacement – an element switches partners: reaction does not always happen; depends on the Activity Series (or reactivity series)
Example of a single replacement that does occur:
Na MgCl2  NaCl + Mg

29. Na is higher up on chart than Mg so Na is more reactive
If a metal is higher on the chart, it will replace a metal that is lower on the chart
Na is higher up on chart than Mg so Na is more reactive

30. NR – Ca is lower on chart than Na
Example 1: Ca ZnI2 
Example 1: Ca ZnI2 
CaI Zn
Example 2: Ca NaI 
NR – Ca is lower on chart than Na
Write NR for No reaction when a reaction does not occur

31. a. calcium, tin d. iron, copper
For each of the following pairs of elements, circle the one that will replace the other element in a compound
a. calcium, tin d. iron, copper
b. bromine, fluorine e. iodine, chlorine
c. aluminum, potassium f. silver, lead

32. More Practice: Skeleton Equations – formulas only
Cu + AgNO3  CuNO3
Ca + HCl  CaCl2 + H2
Mg + CuCl2  MgCl2 + Cu
Fe + CuSO4  FeSO4 + Cu
Zn + HCl  ZnCl2 + H
Cl2 + NaBr  NaCl + Br

33. END

34. new compound + new compound
DOUBLE REPLACEMENT:
AB + CD  CB + AD
compound + compound =
new compound + new compound
Cations and Anions switch places
But there must be a reason why they switch places ……………

35. C+ B­ D­ A+ A gas forms and leaves
A precipitate forms and settles out Water is formed

37. K+ Solubility Rules: 1. Na+ NH4 salts are soluble 2. NO3
­1-
salts are soluble
3. Cl­1- salts are soluble EXCEPT: AgCl PbCl2
and HgCl
4. SO4
2-­
salts are soluble
EXCEPT: BaSO4 PbSO4 and CaSO4

38. Four general types of chemical reactions+ .. + +

39. Four general types of chemical reactions+ .. + +

40. Synthesis

41. Decomposition

42. Synthesis
Decomposition
Single Replacement

43. Synthesis
Decomposition
Single Replacement
Double Replacement

44. •• Produces oxides of the fuel •• Hydrocarbon or any C,H,O compound
COMBUSTION: (Burning)
•• Reacts with oxygen
•• Produces oxides of the fuel
•• Hydrocarbon or any C,H,O compound
•• Produces CO2 and H2O
•• Produces energy (heat and light)
•• Exothermic reaction
•• Example: CH4 + 2O2  CO2 + 2 H2O

45. C + O2  CO2 2Ca + O2  2CaO Na + O2  Na2O
OXIDATION:
•• Metal or nonmetal reacts with oxygen
•• Produces an oxide of the element
•• Exothermic reaction­ produces heat
Examples:
C + O2  CO2
2Ca + O2  2CaO
Na + O2  Na2O

46. •• Synthesis A + B  AB Decomposition AB  A + B Single Replacement
A + BC  B + AC ••
Double Replacement AB + CD  AD + CB
Acid – Base (Neutralization) Acid + Base  Salt + Water Combustion
Oxidation

47. Predicting Products of ReDox Reactions
Synthesis – More than one reactant, but a single product
Example:
2Mg O2  2MgO
Decomposition – A single reactant, multiple products
2KNO3  KNO O2 +2 -2 +1 +3 -2 +1 +5 -2