Ch 23

Section 3

Classifying Chemical Reactions

Combustion   Combustion reaction- occurs when a substance reacts with

oxygen to produce energy in the form of heat and light.

CH4(g) + O2(g) CO2(g) + H2O(l)

Synthesis   Synthesis reaction- two or more substances

combine to form another substance.

A + B → AB

Decomposition   Decomposition reaction- one substance breaks

down, or decomposes, into two or more substances.

AB → A + B   Most decomposition reactions require the use of

heat, light, or electricity.

Single Displacement   Single displacement reaction- When one element

replaces another element in a compound.

A + BC → AC + B

Activity series   Metals that are more active will replace metals that

are least reactive.

Double Displacement   Double displacement reaction- the positive ion of

one compound replaces the positive ion of the other to form two new compounds.

  A double displacement reaction takes place if a precipitate, water, or a gas forms when two ionic compounds in solution are combined.

AB + CD → AD + CB

Double Displacement   Precipitate-an insoluble compound that comes out

of solution during this type of reaction.

Oxidation-Reduction   The Loss of electrons is called oxidation.

  The gain of electrons is called reduction

LEO says GER   Corrosion of metal is a visible result.

Oxidation-Reduction   The substance that gains an electron is being

reduced. (becomes more negative)

  The substance that losses an electron is being oxidized. (becomes more positive)

  Oxidation and reduction go together. We say that it is a Redox reaction.