Types of Chemical Reactions

There are 6 categories for Chemical Reactions  Combustion  Synthesis  Decomposition  Single Displacement  Double Displacement  Acid-Base

COMBUSTION  When oxygen combines with another compound and produces carbon dioxide and water. This is an exothermic reaction meaning they produce heat.  Example: Burning of naphthalene C 10 H O 2 10 CO H 2 O

SYNTHESIS  When two or more simple compounds combine to form a more complicated one.  Example: combination of iron and sulfur to form iron (II) sulfide 8 Fe + S 8 8 FeS

DECOMPOSITION  Opposite of a synthesis reaction – a complex molecule breaks down into simpler ones.  Example: electrolysis of water to make hydrogen and oxygen gas 2 H 2 O 2 H 2 + O 2

SINGLE DISPLACEMENT  One element trades places with another element in a compound.  Example: magnesium replaces hydrogen in water to make magnesium hydroxide and hydrogen gas Mg + 2 H 2 O Mg(OH) 2 + H 2

DOUBLE DISPLACEMENT  When anions and cations of two different molecules switch places forming two entirely different compounds.  Example: lead (II) nitrate reacts with potassium iodide to form lead (II) iodide and potassium nitrate Pb(NO 3 ) KI PbI KNO 3

ACID-BASE  Special kind of double displacement reaction when an acid and base react with each other. H + ions in the acid react with OH - ions in the base to produce water and an ionic salt.  Example: hydrobromic acid reacts sodium hydroxide HBr + NaOH NaBr + H 2 O