1. II. Five basic types of chemical reactions:

2. B. Decomposition:
A single compound breaks down into its component parts or simpler compounds.
Basic form: AX  A  +  X

3. Examples of decomposition reactions:
Metallic carbonates, when heated, form metallic oxides and CO2 .
ex CaCO3   CaO  +  CO2

4. Most metallic hydroxides, when heated, decompose into metallic oxides and water.
ex Ca(OH)2   CaO  +  H2O

5. Metallic chlorates, when heated, decompose into metallic chlorides and oxygen.
ex KClO3   2KCl  +  3O2

6. Some acids, when heated, decompose into nonmetallic oxides and water.
ex H2SO4   H2O  +  SO3

7. Some oxides, when heated, decompose.
ex HgO   2Hg  +  O2

8. Some decomposition reactions are produced by electricity.
ex H2O   2H2  +  O2
ex NaCl   2Na  +  Cl2

9. What do all of these have in common?
CaCO3   CaO  +  CO2
Ca(OH)2   CaO  +  H2O
2KClO3   2KCl  +  3O2
H2SO4   H2O  +  SO3
2HgO   2Hg  +  O2
2H2O    2H2  +  O2

10. Example
Decomposition of ammonium dichromate

11. Practice Predicting Products of Decomposition Reactions

12. D. Ionic or Double Replacement:
occurs between ions in aqueous solution.
A reaction will occur when a pair of ions come together to produce at least one of the following:
a precipitate
a gas
water or some other non-ionized substance.
Basic form: AX  + BY    AY  +  BX

13. Examples of ionic reactions:
#3: Formation of water. (If the reaction is between an acid and a base it is called a neutralization reaction.)
ex. HCl  +  NaOH   NaCl  +  H2O

14. #2 Formation of a gas. ex. HCl + FeS - FeCl2 + H2S
H2S is the only gas you need
to remember.

15. Look for one of these three.
Rewrite equation, replacing unstable compound with products.
Ex. NH4Cl + Ca(OH)2  NH4OH + CaCl2
NH4Cl + Ca(OH)2  NH3  +H2O + CaCl2
Now balance the equation!
Note the up arrow. You must indicate that a gas is produced!

16. #1 Formation of precipitate.
Use Solubility Table
(A solid that was not present in the reactants)
Marked with (s) or 
S mean soluble, or dissolved. No
precipitate is formed.
ALL OTHER LETTERS MEAN THAT
A PRECIPITATE FORMS.
Look up the formulas for your products.
Whichever forms a precipitate is
marked with (s) or  . Any soluble
products are marked (aq).
If no solid forms, write N.R. for
no reaction.

17. Magnesium acetate + sodium carbonate 
Think: It's not an acid + base.
What are the products?
magnesium carbonate and
sodium acetate
Any unstable product?
Look for H2CO3, H2SO3, NH4OH
Not there. Now check for a precipitate.
Magnesium carbonate has a P solid
forms.
Finish equation with a down arrow or (s)
after the magnesium carbonate.

18. Ammonium chloride + barium hydroxide
Example
Ammonium chloride + barium hydroxide

19. Practice Predicting Products of Ionic Reactions

20. Combustion of Hydrocarbons:
Hydrocarbons contain hydrogen and carbon. Some also have oxygen.
When a hydrocarbon is burned with sufficient oxygen supply, the products are always carbon dioxide and water vapor.
Balance in this order: C, H, O

21. If the supply of oxygen is low or restricted, then carbon monoxide will be produced.
This is why it is so dangerous to have an automobile engine running inside a closed garage or to use a charcoal grill indoors.

22. NOTE:
The phrase "To burn" means to add oxygen unless told otherwise.

23. (CxHy) + O2  CO2 + H2O ex. CH4 + 2O2  CO2 + 2H2O

24. C. Single Replacement:
a more active element takes the place of another element in a compound and sets the less active one free.
Basic form: A  +  BX   AX  +  B
 or
AX  +  Y   AY + X

25. Examples of replacement reactions:
ex. Fe  +  CuSO4   FeSO4  +  Cu

26. 2. Replacement of hydrogen in water by an active metal.
ex. 2Na  +  2H2O   2NaOH  +  H2
Only one hydrogen is replaced, leaving
an hydroxide ion.

27. Only these metals will react with water, producing hydrogen gas and metallic hydroxide.

28. 3. Replacement of hydrogen in acids by active metals.
ex. Zn  +  2HCl   ZnCl2  +  H2

29. Only these metals will react with acids, producing hydrogen gas and metallic hydroxide.

30. ex. Cl2  +  2NaBr   2NaCl  +  Br2
The halogen is replaced, NOT the metal! The halogen activity series is Group 17 on the Periodic Table.

31. Examples

32. A. Synthesis (composition):
two or more elements or compounds may combine to form a more complex compound.
Basic form: A  +  X   AX

33. Examples of synthesis reactions
Metal  +  oxygen  metal oxide
ex Mg  +  O2   2MgO

34. Nonmetal  +  oxygen  nonmetallic oxide
ex C  +   O2   CO2

35. Metal oxide  +  water   metallic hydroxide
ex MgO  +   H2O   Mg(OH)2

36. Nonmetallic oxide  +  water   acid
ex CO2  +  H2O    H2CO3

37. Metal + nonmetal   salt
ex Na  +  Cl2   2NaCl

38. A few nonmetals combine with each other.
ex P  +  3Cl2   2PCl3

39. What do all of these have in common?
2Mg  +  O2   2MgO
C  +   O2   CO2
CO2  +  H2O    H2CO3
MgO  +   H2O   Mg(OH)2
2 Na  +  Cl2   2NaCl
2P  +  3Cl2   2PCl3

40. Example Zinc + Iodine zinc iodide Oxygen + Hydrogen  Water
Click on pictures
Oxygen + Hydrogen  Water

41. Practice Predicting Products of Synthesis Reactions

42. Analyzing Chemical Reactions
One Reactant? no
yes
One Product?
Decomposition no
yes
Next slide
Synthesis

43. 2 Ionic Compounds or Acid and Ionic Compound?
yes no
Double Replacement
Next slide
Precipitate Neutralization Gas

44. yes no Element and Compound? Single Replacement Hydrocarbon and O2 no
Metal Halogen Metallic oxide no
Combustion
????

45. Precipitate Gas Neutralization
One Reactant?
yes no
One Product?
Decomposition
yes no
Synthesis
2 Ionic Compounds or Acid and Ionic Compound?
yes no
Double Replacement
Element and Compound?
yes no
Precipitate Gas Neutralization
Hydrocarbon and O2?
Single Replacement
yes no no
Combustion
????