Chemical reactions can be classified in one of two ways: 1. Based on how atoms are reordered 2. Based on how energy/ heat is transferred

Two or more elements/compounds combine to form a single product. General equation: A + B AB 2Mg + O 2 2MgO ABAB

2Mg + O 2 2MgO(white powder) A + B AB

8 Fe + S 8 8 FeS

+

A single reactant/compound, breaks into two or more parts. General equation: AB A + B o 2H 2 O 2 2H 2 O + O 2 B AB A

2H 2 O 2 2H 2 O +O 2 AB A + B Bubbles are O2 Liquid is water. Elephants toothpaste

MgO2 Mg + O2 +

+

A more reactive Single element replaces a less reactive element in a compound. (metal replaces another metal… a non-metal replaces a non- metal) The general equation: A + BC AC + B (Rico Suave Scandal) A BBC AC

Al + CuCl 2 AlCl 3 + Cu Al + CuCl 2 AlCl 3 + Cu A + BC BA + C A + BC BA + C

Mg + 2HCl MgCl 2 + H 2 Mg + 2HCl MgCl 2 + H 2 A + BC BA + C A + BC BA + C What do you know about Hydrogen gas!? What do you know about Hydrogen gas!?

Mg + HCl _____ + _____ If a metal will only replace a metal, and a non-metal will only replace a non-metal… then what will the products be?? Mg kicks out H Mg kicks out H so that Mg can bond with Cl. BUT WAIT!!! H is the leader of the NOF 7 group – so its diatomic! BUT WAIT!!! Is it balanced?? MgCl H

Mg + AlCl 3 ________ + __________ Cl 2 + NaBr ________ + __________ Copper(II) + silver nitrate yields … _____+ _______ _________ + _______ MgCl2 Al NaClBr2 Cu Ag(NO3) Cu(NO3)2 Ag

Single Replacement

++

+ +

Two compounds switch partners to form two new compounds General equation: AB + CD AD + CB KI+ Pb(NO 3 ) 2 KNO 3 + PbI Note: Metals replace metals and non-metals replace non-metals Scandal of Scandals!! AB CBCD AD

KI (aq) + Pb(NO 3 ) 2(aq) KNO 3(aq) + PbI (s) AB + CD AD + CB

MgCl + Ca(SO4) _____ + ________ If a metal will only replace a metal, and a non- metal will only replace a non-metal… then what will the products be?? Mg kicks out Ca Mg kicks out Ca so that Mg can bond with SO4. BUT WAIT!!! Make sure CaCl has the right formula. (Ca 2+ … Cl 1- ) BUT WAIT!!! Is it balanced?? CaCl 2 MgSO4 2

Double Replacement ++

Double Replacement

(NO 3 ) 2 + I K Pb Pb(NO 3 ) 2 + K I KNO3 + PbI2

+ +

A hydrocarbon or alcohol is reacted with oxygen gas to always form the products carbon dioxide and water. General equation: Hydrocarbon + O 2 CO 2 + H 2 O or Alcohol CH

CH 4 + O 2 CO 2 + H 2 O

C 10 H O 2 ---> 10 CO H 2 O Combustion Hint: Look for CO2 and H2O as products!!

Unfortunately we cannot forget about neutralization reactions (a.k.a. acid- base reactions)! Acid and a base react to form a salt and water. General equation: HX + MOH MX +H 2 O HCl + NaOH NaCl + H2O Where M is a metal and X is a non-metal

HBr + NaOH ---> NaBr + H 2 O Neutralization

1. EXOTHERMIC (exo= outside)- energy is released as a product during a chemical reaction given off as heat (hot rxn!!) H2O2 O2 + H2O + Heat (heat is a product) 1. ENDOTHERMIC (endo= inside)- energy is required (a reactant) during a chemical reaction and heat is absorbed (cold rxn!!) 2NH4 + H2O + Heat 2NH4(OH) (heat is a reactant)

Brrr… Sodium acetate in water