Predicting the Products of Chemical
Reactions Refresher
Chemistry
STEPS FOR PREDICTING PRODUCTS
• Classify the reaction based on the reactants
• Predict the products based on the type of
reaction
• Write the formula for each product (Take into
consideration type of bonds, polyatomic ions,
& diatomic elements)
• Balance the chemical equation and use the
solubility table to add state symbols.
Diatomics!
• Remember the elements that exist in diatomic form.
• H, N, O, F, Cl, Br and I
• All exist with two of the atoms bonded together:
• H2 N2 O2 F2 Cl2 , Br2 , I2
Polyatomic Ions!
• MEMORIZE YOUR POLYATOMICS
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Ammonium NH4+1
Hydroxide OH-1
Nitrite NO2-1
Nitrate NO3-1
Hydrogen sulfate HSO4-1
Hydrogen carbonate (bicarbonate) HCO3 -1
Carbonate CO3-2
Sulfate SO4-2
Phosphate PO4 -3
A + B  Synthesis/Combination
• If it is synthesis, write a compound that contains
both elements. (remember to balance the charges
for ionic compounds)
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2 Na(s) + Cl2(g)  2 NaCl
2 elements indicates synthesis
Write Charges for each then write compound
Na+ ClNaCl
Balance Reaction
AB  Decomposition
• A single reactant indicates a decomposition reaction.
• Separate to elements (remember diatomics!) or less
complex compounds
• Examples:
• 2 MgO  2 Mg + O2
•
NH4OH  NH3 + H2O
AB + C  Single Displacement
• Only a more reactive element can displace a less
reactive element!!!!
• AB is an ionic compound and C is an element.
• If element is a metal, it replaces the cation.
• CuSO4 + Zn  Cu + ZnSO4
• If element is a non-metal, it replaces the anion.
• 2 LiI + F2  I2 + 2 LiF
• Remember correct charges and diatomics!
• Then balance at the end.
• Finish with state symbols.
AB + CD  Double Displacement
• AB and CD are both ionic compounds.
• Separate each compound into cation and anion & write
their charges.
• Switch places and re-write new compounds.
• Example:
• Pb(NO3)2 +2 KI  PbI2 + 2 KNO3
• Pb2+ NO3K+
I• Pb2+ I- K+ NO3• Balance at the end with states
CxHy + O2  Combustion
• Can also be CxHyOz
• A hydrocarbon and oxygen indicate a
combustion reaction.
• Just write CO2 and H2O as products and then
balance (this is the hard part!)
•
C4H10 + O2 
CO2 +
H2O