 There are only five (5) different types of chemical reactions:  1) Double Replacement  2) Single Replacement  3) Synthesis  4) Decomposition  5) Combustion

 Occur between two ionic compounds  Does not happen with covalent compounds  Involves an exchange of cations  The cation of one compound trades places with the cation of another compound to form two new compounds

 occur in solution when the compounds are in an aqueous state (aq)  reactants are either aqueous to begin with, or solid compounds dissolved in water to form an aqueous solution of ions  in order to drive the reaction, one of the products must be removed from the aqueous solution  this can occur via one of three ways:

1) Formation of a precipitate (an insoluble solid forms in the solution)  i.e.: AgNO 3 (aq) + NaCl (aq) = NaNO 3 (aq) + AgCl (s)  Solid silver chloride is formed as precipitate and comes out of the solution

2) Formation of a gas  i.e.: FeS (aq) + 2 HCl (aq) = H 2 S (g) + FeCl 2 (aq)  Hydrogen sulfide gas is formed and comes out of the solution

3) Water is formed when a hydrogen cation unites with a hydroxide anion  i.e.: NaOH (aq) + HCl (aq) = HOH (l) + NaCl (aq)  Water (HOH) is formed and comes out of the solution

 Double replacement reactions always have two ionic compounds on the REACTANTS side  *Two compounds react to form two new compounds*  AB + CD  CB + AD  A & C are cations, B & D are anions  A & C switch places

 Atom (s) of a lone element replace the atom (s) of an element in a compound  Metals replace metals (or cations replace cations)  Non-metals replace non-metals (or anions replace anions)

 Metal Cation Replacement:  For the reaction: A + BC  B + AC  A and B are cations  A “replaces” B in the compound

 Non-metal Anion Replacement: For the reaction: D + EF  ED + F D & F are anions D “replaces” F in the compound Non metal replacements usually involve halogens

 Thermite  Thermite is a reaction that creates molten iron from rust and aluminum powder.  This reaction is typically used in certain types of welding (or for just melting stuff) Fe 2 O Al → 2 Fe + Al 2 O 3

 Activity Series:  A characteristic of metals and halogens referring to their reactivity  Determines whether or not a single replacement reaction will occur or not  Metals: on the handout provided there is an activity series of metals arranged in order of decreasing activity  Non-metals (Halogens) : as you move down the group on the periodic table activity decreases

 A single replacement reaction WILL NOT OCCUR if the reactivity of the pure element reactant is less than that of the compound reactant  i.e.: Sn (s) + NaNO 3 (aq)   no reaction b/c tin is less reactive than sodium

 A single replacement reaction WILL OCCUR if the reactivity of the pure element reactant is greater than that of the compound reactant  i.e.: Zn (s) + H 2 SO 4 (aq)  ZnSO 4 (aq) + H 2 (g)  Reaction occurs because the reactivity of zinc is higher than hydrogen

 Single replacement reactions ALWAYS have 1 lone element and 1 compound on the reactants side and the products side  Reactants will always be:  1 lone element + 1 compound  Products will always be:  1 lone element + 1 compound

 Occurs when a single compound breaks down into two or more components  Energy is required for them to occur  Reactants will always be:  1 compound  Products will always be:  ALWAYS more products than reactants  2 components (either compounds or elements)  i.e.:  AB  A + B

 One unit breaks down into its component parts  i.e. – Remember N’Sync? They split up leaving the resulting in Justin Timberlake and four guys we don’t remember.

2 H 2 O 2 (aq) → 2 H 2 O (l) + O 2 (g)  Hydrogen peroxide naturally decomposes into water and oxygen gas  If you have old hydrogen peroxide in your house, it may have turned into a bottle of water  Don’t try and drink it though. Obviously.

 Occurs when two or more components come together to form one compound  Energy is released when these reactions occur  Reactants will always be: ALWAYS more reactants than products! 2 or more components (either elements or compounds)  Products will always be: 1 single compound  i.e.: A + B  AB

 Two individual components coming together to form one unit  i.e. – Beyonce & Jay-Z were both awesome on their own, but joined together to become one, even better entity.

 Decomposition and Synthesis Reactions are opposite processes  Special Case #1:  A non metal oxide + water combine to form an acid  i.e.: SO 3 + H 2 O  H 2 SO 4  AND an acid will decompose to form a non-metal oxide + water  i.e.: H 2 SO 4  SO 3 + H 2 O

 Special Case #2  A metal oxide + water combine to form a metal hydroxide  i.e.: CaO + H 2 O  Ca(OH) 2  A metal hydroxide will decompose into a metal oxide + water  i.e.: Ca(OH) 2  CaO + H 2 O

 Special Case #3:  All carbonates decompose into carbon dioxide and an oxide  i.e.: CaCO 3  CaO + CO 2  Vice versa for synthesis/formation reactions  Special Case #4:  All chlorates decompose into oxygen and a binary salt  i.e.: KClO 3  KCl + O 2  Vice versa for synthesis/formation reactions

 Also known as burning or explosions  Hydrocarbon Compound composed of only carbon and hydrogen and sometimes oxygen  Reactants will always be: Hydrocarbon + oxygen  Products will always be: Carbon dioxide + water  i.e.: C 6 H 6 + O 2  CO 2 + H 2 O