Classification of Chemical Reactions Chemical reactions can be classified in one of two ways: Based on how atoms are rearranged Based on how energy/ heat is transferred Vs.

where A and B may be either elements or compounds SYNTHESIS REACTION This is a reaction in which two or more elements or compounds combine to form a single product. This type of reaction follows the general equation A + B  AB where A and B may be either elements or compounds

where A and B may be either elements or compounds. DECOMPOSITION REACTION In this type of reaction a single reactant, a compound, breaks into two or more parts. Often these are the most difficult to predict. Here is the general equation: BC B + C where A and B may be either elements or compounds. 2H2O2 2H2O +O2

F2 + MgBr2  Br2 + MgF2 Zn + CuCl2  Cu + ZnCl2 SINGLE REPLACEMENT REACTION Single replacement reactions replace one element from a compound with another element. A compound and an element react, and the element switches places with part of the original compound. A + BC  B + AC where A is a metal, or A + BC  C + BA where A is a non-metal F2 + MgBr2  Br2 + MgF2 Zn + CuCl2  Cu + ZnCl2

2KI(aq) + Pb(NO3)2(aq)  2KNO3(aq) + PbI2(s) DOUBLE REPLACEMENT REACTION Double replacement reactions swap elements between 2 compounds that react together to form two new compounds. Two compounds react, with elements switching places between the original compounds. AB + CD  AD + CB 2KI(aq) + Pb(NO3)2(aq)  2KNO3(aq) + PbI2(s) Note: “Metals” replace “metals” and non-metals replace non-metals

Special Double Replacement Reaction: Neutralization Reactions In this type of reaction, an acid and a base react to form a salt and water. The general equation for this type of reaction is: HX + MOH  MX +H2O Where M is a metal ion and X is a non-metal ion HCl + NaOH  NaCl + H2O

CxHy + O2(g)  CO2(g) + H2O(l) or (g) Combustion Reaction In this type of reaction, a hydrocarbon is burned in the presence of oxygen gas to form carbon dioxide and water. Here is the general equation in the presence of plenty of oxygen: CxHy + O2(g)  CO2(g) + H2O(l) or (g) CH4 + O2  CO2 + 2H2O + energy 2C2H2 + 5O2  4CO2 + 2H2O + energy C6H12O6 + 6O2  6CO2 + 6H2O + energy Note: If combustion is inefficient (insufficient oxygen) then carbon monoxide is formed! Acetylene torch

SUMMARY OF REACTIONS

Mixed Practice H2 + Cl2  HCl 3CuCl2 + 2Fe  2FeCl3 + 3Cu State the type (Synthesis, Double Replacement, Single Replacement, Decomposition, Combustion & Neutralization) H2 + Cl2  HCl 3CuCl2 + 2Fe  2FeCl3 + 3Cu H2SO4 + 2KOH  K2SO4 + 2HOH AgNO3 + NaCl  NaNO3 + AgCl C5H12O2 + 7O2  5CO2 + 6H2O 2HgO  2Hg + O2 Synthesis Single Replacement Neutralization Double Replacement Combustion Decomposition

Mixed Practice State the type, predict the products: BaCl2 + CaSO4  Combustion & Neutralization State the type, predict the products: BaCl2 + CaSO4  C6H12 + 9O2  Zn + CuSO4  2Cs + Br2  2H2O  NaOH + H2S  BaSO4 + CaCl2 6CO2 + 6H2O ZnSO4 + Cu 2CsBr 2H2 + O2 NaS + H2O