Post on 23-Mar-2016
description
Single displacement reactions: are chemical changes that involve an element and a compound as reactants
One element displaces or replaces another element from a compound
Single displacement reactions have the following general formula
Z + AB ZB + AOR
Y + AB AY + B
Case 1: the metal Z has taken the place of the element A (metal always replaces metal)
Case 2: the non-metal Y has taken the place of element (non-metal always replaces non-metal)
An example: a coil of magnesium ribbon is placed in a solution of silver nitrate
Magnesium + silver nitrate silver + magnesium
nitrateMg + 2AgNO3 2Ag + Mg(NO3)2
Another example: bromine is added to a solution of calcium iodide
◦ Bromine will replace/displace the iodide ion
Bromine + calcium iodide iodine + calcium bromide
Br2 + CaI2 I2 + CaBr2
Double displacement reactions: occur when elements in different compounds displace each other or exchange places
They have the following general formula:
AB + XY AY + XB
A and X are metallic elements while B and Y are non-metallic elements.
Example: lead (II) nitrate and potassium iodide
Lead (II) nitrate + potassium iodide lead (II) iodide + potassium nitrate
Pb(NO3)2 + 2KI PbI2 + 2KNO3
Pg. 241 # 1-3