Net Ionic Equations

Writing a Complete Ionic Equation

• Start with a balanced molecular equation. • Break all soluble strong electrolytes (compounds

with (aq) beside them) into their ions – indicate the correct formula and charge of each ion – indicate the correct number of each ion – write (aq) after each ion

• Bring down all compounds with (s), (l), or (g) unchanged

2 Na3PO4 (aq) + 3 CaCl2 (aq) --> 6 NaCl (aq) + Ca3(PO4)2 (s)

6 Na+ (aq) + 2 PO43- (aq) + 3 Ca2+ (aq) + 6 Cl- (aq) --> 6 Na+ (aq) + 6 Cl- (aq) +

Ca3(PO4)2 (s)

Spectator Ions

• Spectator ions -are present in the reaction mixture but do not participate in it.

. You can recognize spectator ions by looking for ions that are present on both sides of the equation.

Writing a net ionic equation

Take your complete ionic equation and:• Cross out the spectator ions that are present. • Write the "leftovers" as the net ionic equation.• 6 Na+ (aq) + 2 PO4

3- (aq) + 3 Ca2+ (aq) + 6 Cl- (aq) --> 6 Na+ (aq) + 6 Cl- (aq) + Ca3(PO4)2 (s)

• 2 PO43- (aq) + 3 Ca2+ (aq) --> Ca3(PO4)2 (s)

• 3 (NH4)2CO3 (aq) + 2 Al(NO3)3 (aq) --> 6 NH4NO3 (aq) + Al2(CO3)3 (s)

• 2 NaOH (aq) + H2SO4 (aq) --> Na2SO4 (aq) + 2 H2O (l)

• Mg (s) + 2 HCl (aq) --> MgCl2 (aq) + H2 (g)

• Zn (s) + CuSO4 (aq) --> ZnSO4 (aq) + Cu (s)

• Na2CO3 (aq) + 2 HNO3 (aq) --> 2 NaNO3 (aq) + H2O (l) + CO2 (g)