1. REACTIONS IN AQUEOUS SOLUTIONS
CHAPTER 8-3

2. Net Ionic Equations
Complete ionic equation
Many important reactions take place in water - that is, in aqueous solutions.
Most ionic compounds dissociate, or separate, into cations and anions when they dissolved in water.
In a double replacement reaction like:
AgNO3(aq) + NaCl(aq)  AgCl(s) + NaNO3(aq)
can be written in a complete ionic equation.
Ag+(aq) + NO3- (aq) + Na+(aq) + Cl-(aq)  AgCl(s) + Na+(aq) + NO3- (aq)

3. The net ionic equation is
Spectator ions
Net ionic equation
The equation is then simplified by eliminating ions that do not participate in the reaction, canceling ions that appear on both sides of the equation.
Ions that appear on both sides of the equation are called Spectator ions.
Ag+(aq) + NO3- (aq) + Na+ (aq) + Cl-(aq)  AgCl(s) + Na+ (aq) + NO3- (aq)
Spectator ions = Na+ and NO3- .
The net ionic equation is
Ag+(aq) Cl-(aq)  AgCl(s)

4. Steps to Write Net Ionic Equations
1st Step
2nd Step
Write the normal chemical equations and balance.
Na2SO4 + Ba(NO3)2  BaSO NaNO3
Identify the states of matter of each compound in the equation.
Na2SO4(aq) + Ba(NO3)2 (aq)  BaSO4 (s) + 2 NaNO3 (aq)

5. Complete ionic equation
3rd Step
Complete ionic equation
4th Step
5th Step Net ionic equation
Determine which compounds will dissociate into cations and anions.
Write the complete ionic equation and make sure it is balanced.
2Na+(aq)+ SO4-2(aq)+ Ba+2 + 2NO3-(aq)  BaSO4 (s)+2Na+(aq)+ 2NO3-(aq)
Eliminate spectator ions
2Na+(aq)+ SO4-2(aq)+ Ba+2 (aq) + 2NO3-(aq)  BaSO4 (s)+ 2Na+(aq)+ 2NO3-(aq)
Write net ionic equation
SO4-2(aq) + Ba+2(aq)  BaSO4 (s)