1. Synthesis, Decomposition and Combustion Reactions

2. Synthesis
In a simple synthesis reaction, two elements come together to form a compound
Format: element + element  compound
Must be able to predict
Ex. Words: magnesium + oxygen  magnesium oxide
Formula: Mg + O2  MgO
Practice: Al + Cl2  _______ (Answer is not AlCl2, look at ions)
There are also 2 other formats that you must be able to identify as synthesis, but do not have to predict
Format 1: element + smaller compound  larger compound
Ex. CO + O2  CO2
Format 2: smaller compound + smaller compound  larger compound
Ex. Na2O +CO2 ---> Na2CO3

3. Decomposition
In a simple decomposition reaction, one compound decomposes into two pure elements
Format: compound  element + element
Ex. MgO  Mg + O2
Practice: H2O  _____ (answer is not H2 + O)
There are 2 other formats that you must be able to identify as synthesis, but do not have to predict
Format 1: larger compound  element + smaller compound
Ex. H2O2  H2O + H2
Format 2: larger compound  smaller compound + smaller compound
Ex. NH4NO3  N2O + H2O

4. Combustion
In a combustion reaction, a hydrocarbon reacts with oxygen to make CO2 and H2O
Format: hydrocarbon + O2  CO2 + H2O
Hydrocarbons contain C, H and O
Examples of hydrocarbons:
CH4 (methane), C3H8O(isopropyl alcohol)
Combustion Examples:
CH4 + O2  CO2 + H2O
C3H8O + O2  CO2 + H2O
Practice: C8H18 + O2 