Misty Hardcastle
STUDENT NAME
_________________________________
CHEMISTRY 1 (All Classes)
CLASS PERIOD
1 2 3 4 5 6 7 8
Predicting Products Notes
DATE
___________________
Predicting Products for Chemical Reactions
If you know the Reactants of a chemical reaction, you should be able to predict
the Products of that reaction.
To write the "correct" chemical formulas for the Products, keep these things in mind:

There are 7 elements that MUST have a subscript of 2 when they are found
ALONE in a chemical equation − the diatomic molecules.

NEVER change a subscript that is part of the chemical formula of a polyatomic
ion.

ALL other subscripts (and subscripts found outside parentheses around a
polyatomic ion) are there to make the oxidation numbers in the chemical formula
total zero. These subscripts DO NOT automaticallytransfer from the reactant side
to the product side!
In the five examples below, we are NOT concerned with writing "balanced" equations.
We are ONLY concerned with writing the correct chemical formulas for the reaction
products!
All simple Decomposition Reactions begin with: compound →






In the example: H2O →
break the compound into its individual elements, H and O
H+O
When elements are ALONE in an equation, ask yourself "are they one of the 7
diatomic molecules?"
In this case, both of the products ARE diatomic molecules.
The correct chemical equation is: H2O → H2 + O2
All simple Synthesis Reactions begin with: element + element →




In the example: O2 + Al →
Combine the elements to make a compound.
Write the metal (element with a positive oxidation number) first and the nonmetal
(element with a negative oxidation number second.
AlO
1
Misty Hardcastle
STUDENT NAME
_________________________________


CHEMISTRY 1 (All Classes)
CLASS PERIOD
1 2 3 4 5 6 7 8
Predicting Products Notes
DATE
___________________
Now use subscripts to make the oxidation numbers total zero. (aluminum is +3
and oxygen is −2)
The correct chemical equation is: O2 + Al → Al2O3
All simple Single Displacement Reactions begin with: element + compound →







In the example: Zn + HCl →
Zinc (with a positive oxidation number) will switch places with the positive part of
the compound.
H + ZnCl
Is hydrogen one of the diatomic molecules?
(yes, it must have a subscript of 2) H2 + ZnCl
Use subscripts to make the oxidation numbers in the compound total zero. (Zn is
+2 and Cl is −1)
The correct chemical equation is: Zn + HCl → H2 + ZnCl2
All simple Double Displacement Reactions begin with: compound + compound
→





In the example: FeCl3 + NH4OH →
Switch the positive parts of the two compounds.
NH4Cl + FeOH
Use subscripts to make the oxidation numbers in both compounds total zero.
 The polyatomic ion NH4 is +1
 Chlorine is −1
 Fe is +3 on the left and you can assume it will remain +3 on the right
 The polyatomic ion OH is −1
The correct chemical equation is: FeCl3 + NH4OH → NH4Cl + Fe(OH)3
All simple Combustion Reactions begin with: hydrocarbon + oxygen →



In the example: C6H6 + O2 →
The products of combustion are ALWAYS carbon dioxide and water.
The correct chemical equation is: C6H6 + O2 → CO2 + H2O
2
Misty Hardcastle
STUDENT NAME
_________________________________
CHEMISTRY 1 (All Classes)
CLASS PERIOD
1 2 3 4 5 6 7 8
Predicting Products Notes
DATE
___________________
Predicting Reactions
Directions – Looking at the equations below, using the above notes and your periodic table, #1.)
determine the PRODUCTS FOR EACH REACTION, #2.) BALANCE THE EQUATION AFTER
PRODUCTS ARE MADE, #3.) GIVE THE RATIO FOR THE EQUATION, AND #4.) LIST 1 OF THE 5
TYPES OF CHEMICAL REACTIONS, ie. Synthesis; Decomposition; Combustion; Single Displacement
(Single Replacement); Double Displacement (Double Replacement); Acid-Base Reaction. Remember show
your work!!!
1)
____ Na + ____ FeBr3 
Separate each compound into its ionic form. That is using the periodic table to find the ion charge,
your notes on your periodic table you should have written in +1, +2, +3, +/-4, -3, -2, -1, 0 . After
each element is put in its ionic form (element with a + or – charge), switch the positive elements
place with the other positive element or the negative element just not both or you will end up with
the same compounds. Put them back together with the new matched element and make into a
compound (H2O) or molecule (H2). If you have a single element its ionic charge goes away and
depending on if it is a solid or liquid will determine the subscript, a solid has no subscript, a gas will
have a subscript of 2 ( ex. Fe+3 (iron) is a solid so it is Fe and He0 (helium) is a gas so it is He2.
1.
____ Na +
____ FeBr3
2.
__3__ Na + ___1___ FeBr3 

Na+1
+
Fe+3
___3____ NaBr +
Br-1 (Na+1 Br-1 + Fe+3 )
___1____ Fe
*** Remember that the #1 does not need or have to be written, remember it is assumed to be
there. If you need to write it currently to learn what you are doing then go ahead, you will not be
penalized for it.
2)
3.
Reaction = Single Displacement (Single Replacement)
4.
Ration = 3 : 1 : 3 : 1
____ NaOH + ____ H2SO4 
1. Na+1 OH-1 + H+1 SO4-2 
Na+1 SO4-2 +
2. __2__ NaOH + __1__ H2SO4

H+1 OH-1
___1____Na2SO4 + __2___ HOH (H2O)
3. Reaction = Double Displacement (Double Replacement)
4. Ratio
= 2:1:1:2
3
Misty Hardcastle
STUDENT NAME
_________________________________
3)
____ C2H4O2 + ____ O2 
4)
____ NH3 + ____ H2O 
5)
____ PbSO4 + ____ AgNO3 
6)
____ PBr3 
7)
____ HBr + ____ Fe 
CHEMISTRY 1 (All Classes)
CLASS PERIOD
1 2 3 4 5 6 7 8
Predicting Products Notes
DATE
___________________
4
Misty Hardcastle
STUDENT NAME
_________________________________
8)
____ KMnO4 + ____ ZnCl2 
9)
____MnO2 + ____ Sn(OH)4 
10)
____ O2 + ____ C5H12O2 
11)
____ H2O2 
12)
____ PtCl4 + ____ Cl2 
CHEMISTRY 1 (All Classes)
CLASS PERIOD
1 2 3 4 5 6 7 8
Predicting Products Notes
DATE
___________________
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