Download PreAP Chemistry Reaction Rules

PreAP Chemistry Reaction Rules
Double Replacement = 2 compounds yield 2 different compounds
The oxidation number of the metal stays the same from reactant to product
Hint: if water is involved, write it as HOH
*Probably will NOT be a Redox Reaction
Single Replacement = 1 element and 1 compound yield 1 different element and 1 different compound
Use the preferred oxidation number for the metal/nonmetal (to the right of this sheet)
Hint: if water is involved, write it as HOH
*Probably will be a Redox Reaction
Synthesis (also called Combination) = 2 or more substances yield only 1 compound
*Could be a Redox Reaction
A. Formation of a Binary Compound
2 elements yield 1 binary compound
Use the preferred oxidation number for the metal/nonmetal (to the right)
B. Formation of an Oxyacid (H with polyatomic ion containing oxygen)
Nonmetallic oxide and water yield an oxyacid
Use NOTE 1 below to determine if the polyatomic ion is “ate” or “ite”
C. Formation of a Base (metal with hydroxide)
Metallic oxide and water yield a base
The oxidation number of the metal stays the same from reactant to product
D. Formation of an Oxysalt (metal with polyatomic ion containing oxygen)
Nonmetallic oxide and metallic oxide yield an oxysalt
Metal retains the oxidation number from oxide, use NOTE 1 below to
determine if the polyatomic ion is “ate” or “ite”
Decomposition = 1 compound yields 2 or more simpler substances
*Could be a Redox Reaction
A. Decomposition of a Binary Compound
1 binary compound yields two elements
Watch for diatomic elements
B. Decomposition of an Oxyacid (H with polyatomic ion containing oxygen)
Oxyacid yields nonmetallic oxide and water
Reverse NOTE 1 below to determine oxidation number on nonmetal
C. Decomposition of a Base (metal with hydroxide)
Base yields metallic oxide and water
Metal retains the oxidation number from its base form
D. Decomposition of an Oxysalt (metal with polyatomic ion containing oxygen)
Oxysalt yields nonmetallic oxide and metallic oxide
Metal retains the oxidation number from oxysalt, reverse NOTE 1 below for
the oxidation number on the nonmetal
*A Redox (Reduction-Oxidation) Reaction is any reaction where the oxidation number
(charge/valence) changes during the reaction.
NOTE 1:

High oxidation number on the nonmetal ↔ “ate” polyatomic ion
(keeps oxidation number the same)

Low oxidation number on the nonmetal ↔ “ite” polyatomic ion
(keeps oxidation number the same)
NOTE 2:

Excess positive source (or limited negative source) = use low positive oxidation number in
the resulting compound

Limited positive source (or excess negative source) = use high positive oxidation number
in the resulting compound
Preferred
Oxidation
Numbers
Sb+3
As+3
Bi+3
Br-1
C+4
Cl-1
Cr+3
Co+2
Cu+2
Au+3
H+1
I-1
Fe+3
Pb+2
Mn+2
Hg+2
Ni+2
N+3
P+5
S+6
Sn+4
Don’t
forget the
diatomic
elements