CLASSIFYING CHEMICAL REACTIONS

FIVE BASIC WAYS TO CLASSIFY CHEMICAL REACTIONS: Synthesis Decomposition Single-Replacement Double-Replacement Combustion

Synthesis Reactions: Generic Reaction X + Y-->XY Definition-In this equation, X and Y can be compounds or elements. The result XY is a compound. Analogy- Like a marriage 2 Reactants and 1 Product

Examples of Real Synthesis Reactions: 2Ba + O2 -->2BaO 4Cu + O2 -->2Cu2O 2Cu + O2 -->2CuO 2H2 + O2 -->2H2O C + O2 -->CO2 2Na + Cl2 -->2NaCl 2

Decomposition Reactions: In a decomposition reaction, an compound is broken down into two simpler substances. The generic formula of a decomposition reaction is: XY --> X + Y Decomposition reactions are the opposite of synthesis reactions. Analogy-Like divorce 1 Reactant and 2 Products

Examples of Real Decomposition Reactions: 2HgO --> 2Hg + O2 2H2O --> 2H2 + O2 CaCO3 --> CaO + CO2 Cu(OH)2 --> CuO + H2O 2KClO3 --> 2KCl + 3O2 H2SO4 --> SO3 + H2O

Single Replacement Reactions: In this type of reaction, one element replaces a similar element in a compound. A + XY --> AY + X In this equation, A, X, and Y are the elements and XY, AY, and XA are the compounds. Aggressive metal wins 1 free element + compound  compound + 1 free element Like finding a new girl friend

Li Rb K Ca Na Mg Al Mn Zn Fe Ni Sn Pb Cu Ag PtAu Metal Reactivity Chart Most aggressive metal (woman) wins out H

Examples of Single Replacement Reactions: 2Al + 3Fe(NO3)2  3Fe + 2Al(NO3)3 Zn + CuCl2  Mg + Pb(NO3)2  Fe + Na3PO4  2K + ZnCl2 

Examples of Real Single Replacement Reactions: 2Al + 3Fe(NO3)2  3Fe + 2Al(NO3)3 Zn + CuCl2  Cu + ZnCl2 Mg + Pb(NO3)2  Pb + Mg (NO3)2 Fe + Na3PO4  N.R. 2K + ZnCl2  2 KCl + Zn Cl2 + 2KBr  2KCl + Br2

Double-Replacement Reactions: In a double-replacement reaction, the two compounds exchange places in a solution to form two new compounds. The general equation of a double-replacement reaction is: AB + XY --> AY + XB Like switching partners in square dancing 2 compounds  2 compounds

Examples of Real Double-Replacement Reactions: Pb(NO3)2 + 2KI --> PbI2 + 2KNO3 FeS + 2HCl --> H2S + FeCl2 HCl + NaOH --> NaCl + H2O “lets take turns dancing with these two beautiful ladies”

Combustion Reactions: When a substance combines with oxygen releasing a large amount of energy in the form of light and heat, it is a combustion reaction. Oxygen is needed to Burn things. Generic C + O2  CO2 + heat

Examples of Real Combustion Reactions: examples of combustion reactions C3H8 + 5O2 --> 3CO2 + 4H2O + heat 2CH4 + 4O2  2CO2 + 4H2O + heat

FIVE BASIC WAYS TO CLASSIFY CHEMICAL REACTIONS: Synthesis 2 reactants1 product (like marriage) Decomposition 1 reactant 2 products(like divorce) Single-Replacement(most aggressive element wins) Double-Replacement (switch partners) Combustion=Burning (need oxygen to burn things)