Major Types of Reactions The 4 5 Major Types of Reactions

Synthesis Decomposition Single Displacement Double Displacement We can classify any reaction in the universe as 1 of 5 types based on the reactants and the products. We can use a general equation (using X,Y or Z to represent any element) to show what will happen overall. These 5 types are : Synthesis Decomposition Single Displacement Double Displacement Complete Combustion

Synthesis Reactions idea : 2 or more reactants come together to make 1 product general equation : X + Y  XY examples : 2H2 (g) + O2 (g)  2H2O(l) + thermal energy thermal energy + N2 (g) + O2 (g)  2NO (g) note: that a synthesis reaction may be endothermic or exothermic

Decomposition Reactions idea : 1 compound will break down into 2 or more simpler compounds or elements (this is the reverse of a synthesis reaction) general equation : XY  X + Y examples : H2CO3(aq) CO2 (g) + H2O(l) carbonic acid carbon dioxide water NH4NO3(s)  2H2O(l)+ N2O(g)

Single Displacement Reactions idea : an element can be reacted with a compound and it will trade places with one of its 2 parts general equation : X + YZ  Y + XZ examples : Mg (s) + 2HCl (aq)  MgCl2 (s) + H2 (g) F2 (g) + 2 HCl (aq)  ??? 2Ag(NO3) (aq) + Cu (s) Cu(NO3)2 (aq) + 2Ag (s) 2Na (s) + 2H-OH (l)  2Na(OH) (aq) + H2 (g)

Double Displacement Reactions idea : 2 compounds are reacted together and the first part of each compound will switch places general equation : WX + YZ  WZ + YX examples : NaOH (aq)+ HCl (aq)  NaCl (aq) + H-OH (l) Ba(OH)2 (aq)+Na2(SO4) (aq)  Ba(SO4) (aq) + 2 NaOH (aq)

Complete Combustion Idea: the addition of a hydrocarbon to oxygen in the presence of a spark or flame will generate liquid water and carbon dioxide gas General equation: CxHy +?O2 (g)? CO2 (g) + y/2 H2O (l) Example: C3H8 (g) + 5 O2 (g)  3 CO2 (g) + 4 H2O (l)

Practice p. 121 4-7 p. 128 1 -4 p. 138 1-3