Predicting Products of a Reaction
Will a reaction take place?
If so, what will be produced?
Predicting Products
• NOT just a shot
in the dark!
• Rules govern
whether or not
reactants will
form new
products.
Predicting Single Replacement
Reaction
1. Decide which element is a metal and nonmetal.
Decide which part is positive and negative.
METAL
+2
METAL NON
-1
+1
METAL
+2
NON
-1
METAL
+1
Predicting Single Replacement
• 2. USE ACTIVITY SERIES CHART from reference table to
see if loner metal is higher than metal in compound.
• If YES  the reaction proceeds, higher metal displaces
the lower metal
• If NO  the reaction will not occur.
• Examine Activity Series of Metals
• Examine Activity Series of Halogens
No RXN!
HIGHER REPLACES LOWER!
Activity Series of Halogens
HIGHER REPLACES LOWER
Predicting Single Replacement
• 3. Higher REPLACES lower
• metal replaces metal
• halogen replaces halogen
Predicting Single Replacement
4. Write correct formulas for new products!
• Remember ionic compounds (criss x cross)
• Remember diatomic gases (Br2 I2 N2 Cl2 H2 O2 F2)
Predicting Single Replacement
5. BALANCE EQUATION by balancing coefficients.
EXAMPLE
2 Fe + 6 HCl
 2 FeCl3
+ 3 H2
Iron (Fe) will try to replace the hydrogen (H) in HCl.
Can Iron (Fe) replace the hydrogen (H) in HCl?
Check Activity Series!
Is Fe higher than H?
YES
Iron (Fe) replaces the hydrogen (H) in HCl and bonds
with chloride (Cl) bumping out (H) from the compound.
Final Step is ALWAYS BALANCE!
Predicting Double Replacement
1. Divide molecules into + and - halves.
•
Positive halves switch partners!
Predicting Double Replacement
2. Write correct formula for new molecules on
product side by criss x crossing charges.
+1
-1
+2
-2
NaOH (aq) + CaSO4 (aq) 
+1
-2
+2
-1
Na2SO4 + Ca(OH)2
Predicting Double Replacement
3. Balance the EQUATION!
2 NaOH (aq) + CaSO4 (aq)  Na2SO4 + Ca(OH)2
Predicting Double Replacement
4. Decide which product will be a solid and which will be
aqueous. Watch this
http://phet.colorado.edu/en/simulations/category/ch
emistry
• USE SOLUBILITY RULES! Reference Table
• (s) INSOLUBLE  does not dissolve in water,
• (aq) SOLUBLE  dissolves in water
ppt
2 NaOH (aq) + CaSO4 (aq)  Na2SO4 + Ca(OH)2
(s)
(aq)
Predicting Double Replacement
5. IF both products are aqueous, then no reaction
occurs.