Introduction to Chemical Reactions Learning Reaction Types and Their Patterns

Chemical Reactions

Synthesis A + B  AB Element A + Element B  Compound AB Magnesium Strip + Oxygen Gas  Solid Magnesium Oxide

2 Mg(s) + O2 (g)  2 MgO (s) (white powder)

Decomposition AB  A + B Compound AB  Element A + Element B Aqueous hydrogen peroxide  oxygen gas + liquid water

Splint Test A test used to determine the production of one of the following gases: O2 – flame gets bigger and splint will relight CO2 – flame will go out H2 – popping noise (flame may go out from mini explosion!)

2 H2O2 (aq)  O2 (g) + 2 H2O (l)

ABCD  AB + C + D Compound ABCD  Compound AB + Element C + Element D Solid ammonium dichromate  solid chromium (III) oxide + nitrogen gas + water vapor

ABCD  AB + C + D Compound ABCD  Compound AB + Element C + Element D Solid ammonium dichromate  solid chromium (III) oxide + nitrogen gas + water vapor

(NH4)2Cr2O7 (s)  N2 (g) + Cr2O3 (s) + 4 H2O (g)

Single Replacement - Cationic A + BC  B + AC Element A+ Compound BC Element B+ Compound AC Note: Elements A & B are metals Copper wire + aqueous silver nitrate  solid silver + aqueous copper (I) nitrate

Cu(s) + AgNO3 (aq)  Ag(s) + CuNO3 (aq) (blue)

Iron nail + copper (II) chloride solution  solid copper + iron (II) chloride solution

Fe(s) + CuCl2 (aq)  FeCl2 (aq) + Cu (s) (red)

Solid zinc + aqueous hydrochloric acid  hydrogen gas + aqueous zinc chloride

Zn(s) + 2HCl(aq)  ZnCl2 (aq) + H2 (g) (“pop” splint test)

Single Replacement - Anionic A + BC  C + BA Element A + Compound BC  Element C + Compound BA Note: Elements A & C are nonmetals

Chlorine gas + aluminum bromide solution  bromine gas + aluminum chloride solution

3Cl2 (g) + 2AlBr3 (aq)  3Br2 (g) + 2AlCl3 (aq)

Double Replacement AB + CD  AD + CB Compound AB + Compound CD  Compound AD + Compound BC aqueous copper (II) nitrate + aqueous sodium hydroxide  copper (II) hydroxide (ppt) + aqueous sodium nitrate.

Cu (NO3)2 (aq) + 2 NaOH (aq)  Cu (OH)2 (s) + 2 NaNO3 (aq)

aqueous silver nitrate + potassium chromate  aqueous potassium nitrate + solid silver chromate

AgNO3 (aq) + K2CrO4 (aq)  KNO3 (aq) + Ag2CrO4 (s)

In order for a double replacement reaction to occur, one of the following must be produced: Gas Water Precipitate (ppt.)

Precipitation Animation http://www.mhhe.com/physsci/chemistry/animations/chang_7e_esp/crm3s2_3.swf

Combustion Hydrocarbon + oxygen  carbon dioxide + water + heat Hydrocarbon is a compound containing carbon, hydrogen and sometimes oxygen (CxHyOz) aqueous methanol + oxygen gas  carbon dioxide gas + liquid water

2 CH3OH(aq) + 3 O2 (g)  2 CO2 (g) + 4 H2O (l) + heat

methane gas + oxygen gas  carbon dioxide gas + water vapor

CH4 (g) + 2O2 (g)  CO2 (g) + 2H2O(g)