Types of Chemical Reactions Chemical Equations & Reactions Types of Chemical Reactions

General Types of Reactions Simple Binary (only 2 elements involved) Synthesis Decomposition “Redox” (Oxidation-reduction) Single Replacement Combustion “Double Replacement” Precipitate Acid-Base

A + B  AB Synthesis also known as a combination reaction the combination of 2 or more substances to form a compound only one product A + B  AB

Synthesis 2 Al(s)+ 3 Cl2(g)  2 AlCl3(s) Products: ionic ~ cancel charges covalent ~ hard to tell 2 Al(s)+ 3 Cl2(g)  2 AlCl3(s)

Decomposition a compound breaks down into 2 or more simpler substances only one reactant most occur only when energy in the form of electricity or heat is added AB  A + B

Decomposition 2 H2O(l)  2 H2(g) + O2(g) Electrolysis of Water

Decomposition KBr(l)  2 2 K(s) + Br2(l) Products: binary ~ break into elements others ~ hard to tell KBr(l)  2 2 K(s) + Br2(l)

Decomposition NOT Dissociation products in decomposition reactions are neutral molecules or atoms Dissociation– when soluble, ionic compounds separate into ions no NEW substance produced physical not chemical change More on that later….  NaCl(s)  Na1+(aq) + Cl1-(aq)

CH4(g) + 2O2(g)  CO2(g) + 2H2O(g) Combustion the burning of any substance in O2 releasing energy (exothermic) in the form of light and heat A + O2  B CH4(g) + 2O2(g)  CO2(g) + 2H2O(g)

Combustion 4 Na(s) + O2(g)  2 Na2O(s) Products: Must contain oxygen Hydrocarbons (CxHx) form CO2 + H2O 4 Na(s) + O2(g)  2 Na2O(s) C3H8(g) + 5 O2(g)  3 CO2(g) + 4 H2O(g)

A + BC  B + AC Single Replacement also known as displacement one element replaces another in a compound metal replaces metal (+) nonmetal replaces nonmetal (-) A + BC  B + AC

Cu(s) + 2AgNO3(aq)  Cu(NO3)2(aq) + 2Ag(s) SR - Example Cu(s) + 2AgNO3(aq)  Cu(NO3)2(aq) + 2Ag(s)

The Activity Series of Metals Lithium Potassium Calcium Sodium Magnesium Aluminum Zinc Chromium Iron Nickel Lead Hydrogen Bismuth Copper Mercury Silver Platinum Gold Metals can replace other metals provided that they are above the metal that they are trying to replace. Increasing Activity Metals above hydrogen can replace hydrogen in acids. Metals from sodium upward can replace hydrogen in water. See back of PT!!

The Activity Series of the Halogens Halogens can replace other halogens, if they are above the halogen that they are trying to replace on the periodic table. Fluorine Chlorine Bromine Iodine 2NaCl(s) + F2(g)  2NaF(s) + Cl2(g) ??? MgCl2(s) + Br2(g)  No Reaction ???

AB + CD  AD + CB Double Replacement ions in two compounds “change partners” cation of one compound combines with anion of the other AB + CD  AD + CB

Pb(NO3)2(aq) + K2CrO4(aq)  PbCrO4(s) + 2KNO3(aq) DR - Example Pb(NO3)2(aq) + K2CrO4(aq)  PbCrO4(s) + 2KNO3(aq)

Double Replacement NaNO3(aq) + KI(aq)  N.R. Products: switch negative ions one product MUST BE (insoluble) precipitate, water, or gas (check solubility rules on back of PT) Pb(NO3)2(aq) + 2 KI(aq)  PbI2(s) + 2 KNO3(aq) NaNO3(aq) + KI(aq)  N.R.