Types of Chemical Reactions

Chemical Reactions

• grouped into categories• based on reactions following the same pattern

Synthesis• two simple reactants combine to make a

larger or more complex product• the general pattern is:

A + B AB• the reactants can be either atoms (elements)

or molecules (elements or compounds)

ExamplesSynthesis reaction Equation

zinc sulfide zinc + sulfur zinc sulfideZn(s) + S(s) ZnS (s)

sodium chloride sodium + chlorine sodium chloride Na(s) + Cl2(g) NaCl (s)

ammonium chloride ammonia + hydrogen chloride ammonium chloride NH3 (g) + HCl (g) NH4Cl (s)

GENERAL PATTERN A + B AB

produces zinc sulfide powder

produces sodium chloride

produces cloudy white ammonium chloride powder

Decomposition• large compounds broken down into smaller

compounds or elements• the general pattern is:

AB A + B• often absorb energy from external source and

converts products into reactants

• decomposition happens when the stability of a chemical compound is limited by exposure to an adverse condition

• examples include heat, radiation, humidity or the acidity of a solvent

ExamplesDecomposition Reaction Equation

water energy + water hydrogen + oxygen H2O(l) H2 (g) + O2 (g)

sodium azide energy + sodium azide sodium + nitrogen NaN3 Na (s) + N2 (g)

GENERAL PATTERN AB A + B

http://www.youtube.com/watch?v=dZfLOnXoVOQ

Homework: p. 239 #1,2,4