5.2 Displacement Reactions
Learning Goals
• Learn how to read and use the activity series
• Learn what is a single displacement reaction and
how to create a single displacement reactions
• Learn what is a double displacement reaction and
how to create a double displacement reaction
Classifying Chemical Reactions
•
The new substances, or products, that form during chemical changes
will depend on the type of chemical reaction occurring.
•
There are four main types of chemical reactions:
1) Synthesis Reactions
2) Decomposition Reactions
3) Single Displacement Reactions
4) Double Displacement Reactions
Single Displacement Reactions
In a single displacement reaction, one element takes the place of (displaces)
another element in a compound.
There are two general forms of equations for a single displacement reaction:
For a single displacement, where A is a metal:
For a single displacement, where A is a non-metal:
Example 1
A single displacement reaction involving a metal replacing another metal
occurs when copper is placed in an aqueous solution of silver nitrate.
copper + silver nitrate  copper(II) nitrate + silver
Cu(s) + AgNO3(aq)  Cu(NO3)2(aq) + Ag(s)
Cu(s)
Cu(s)++2AgNO
AgNO3(aq)  Cu(NO3)2(aq) + Ag(s)
2Ag(s)
Metals differ in their reactivity. The
activity series is a list of metals
organized according to their chemical
reactivity; the most reactive metal
appears at the top and the least
reactive metal appears at the bottom.
A reactive metal will displace or
replace a metal in a compound that is
below it in the activity series.
Looking back at the previous example:
Cu(s) + 2AgNO3(aq)  Cu(NO3)2(aq) + 2Ag(s)
Could it be the other way around?
Ag(s) + Cu(NO3)2(aq)  No reaction
Example 2
A single displacement reaction involving a metal replacing hydrogen
occurs when zinc is placed in an aqueous solution of hydrochloric acid
(hydrogen chloride).
zinc + hydrochloric acid  zinc chloride + hydrogen
Zn(s) + HCl(aq)  ZnCl2(aq) + H2(g)
Zn(s) + 2HCl(aq)  ZnCl2(aq) + H2(g)
Example 3
A single displacement reaction involving a non-metal replacing another
non-metal occurs when fluorine is placed in an aqueous solution of
potassium iodide.
fluorine + potassium iodide  potassium fluoride + iodine
F2(g) + KI(aq)  KF(aq) + I2(g)
F2(g) + 2KI(aq)  2KF(aq) + I2(g)
Double Displacement Reactions
In a double displacement reaction, the cations of two different compounds
exchange places, forming two new compounds.
The general form of the equation is:
In this equation, A and C are cations and B and D are anions.
Example
An example of a double displacement reaction occurs when barium
hydroxide and sodium sulfate are mixed in a solution.
barium hydroxide + sodium sulfate  barium sulfate + sodium chloride
Ba(OH)2(aq) + Na2SO4(aq)  BaSO4(s) + NaOH(aq)
Ba(OH)2(aq) + Na2SO4(aq)  BaSO4(s) + 2NaOH(aq)
Example
The following is a double displacement reaction.
Complete and balance the chemical equation.
AlCl3(aq) + CuNO3(aq) 
Homework
Textbook:
• Read Section 5.2
• Questions pg 193 # 1, pg 196 # 1
Formal Lab Report Due Thursday!