Classes of Reaction Equations

There are five general classes of reaction equations Synthesis Decomposition Single displacement Double displacement Combustion

Reaction Equations Each reaction type has a basic formula. We will use letters to represent the atoms in the general formulas. A specific and real example will be presented last.

Synthesis Basically you have two reactants, but only one product. General Equation is: A + B  AB Examples: H2 + O2 -> H2O Mg + O2 -> MgO

Decomposition General equation is: AB  A + B It starts with one reactant and ends up with two or more products. General equation is: AB  A + B Example: H2O2 -> H2O + O2

Single Displacement/Replacement The reaction starts with one element and one compound. The reaction ends up with a different element and a different compound.

Single Displacement/Replacement Generally: A + BC  AC + B (cation exchange) or A + BC  BA + C (anion exchange)

Single Displacement/Replacement Example: CuCl2 + Al -> AlCl3 + Cu

Double Displacement/Replacement The equation starts with two compounds and ends with two new compounds.

Double Displacement/replacement General equation: AB + CD - AD + CB Notice: cations stay cations Example: AgNO3 + NaCl -> AgCl + NaNO3

Combustion A hydrocarbon burns with oxygen to form carbon dioxide and water. A hydrocarbon is hydrogen and carbon containing compounds.

Combustion General equation: Hydrocarbon + O2 CO2+H2O Example: CH3CH3 + O2 -> CO2 + H2O http://www.youtube.com/watch?v=gXcug7RqPgs