Net Ionic Equations mixing ionic compounds

Ionic interactions When you dissolve 2 or more ionic compounds in water some parts of it may react together and precipitate out When you dissolve 2 or more ionic compounds in water some parts of it may react together and precipitate out Precipitate-solid falling out of solution Precipitate-solid falling out of solution More times than not, most (if not all) of the ions do nothing More times than not, most (if not all) of the ions do nothing Net ionic equations are only concerned with the ions that do something Net ionic equations are only concerned with the ions that do something

This goes back to ionic dissociation in water NaCl (s) + AgNO 3(s) in water  Na + (aq) + Cl - (aq) + Ag + (aq) + NO 3 - (aq)  Here’s the trick, AgCl is insoluble AgCl (s) + Na + (aq) + NO 3 - (aq) Net ionic ignores everything that doesn’t do anything! Ag + (aq) + Cl - (aq)  AgCl (s) net ionic equation-- 

More net ionic equations You normally write the reactants as aqueous (since you are dissolving them) You normally write the reactants as aqueous (since you are dissolving them) Mg(NO 3 ) 2(aq) + Na 2 CO 3(aq)  MgCO 3(s) + 2NaNO 3(aq) Mg(NO 3 ) 2(aq) + Na 2 CO 3(aq)  MgCO 3(s) + 2NaNO 3(aq) Dissociate everything that is aqueous, not solid Dissociate everything that is aqueous, not solid Mg NO Na + + CO 3 -- Mg NO Na + + CO 3 --   MgCO 3(s) + 2 Na + + 2NO 3 - Now cancel out everything that is the same on both sides of the equation Now cancel out everything that is the same on both sides of the equation These are called spectator ions These are called spectator ions The remaining part is the net ionic equation Mg ++ + CO 3 --  MgCO 3(s)

What if nothing precipitates out? K 2 SO 4(aq) +AgNO 3(aq)  KNO 3(aq) + Ag 2 SO 4(aq) K 2 SO 4(aq) +AgNO 3(aq)  KNO 3(aq) + Ag 2 SO 4(aq) (by the way, this equation isn’t balanced) (by the way, this equation isn’t balanced) 2 K + + SO Ag + + NO 3 -  2 K + + SO Ag + + NO 3 -  K + + NO Ag + + SO 4 2- K + + NO Ag + + SO 4 2- Everything cancels out Everything cancels out There is no net ionic equation There is no net ionic equation

Practice with equations that are not yet balanced K 2 CO 3(aq) + Ca(NO 3 ) 2( aq)  KNO 3(aq) + CaCO 3(s) K 2 CO 3(aq) + Ca(NO 3 ) 2( aq)  KNO 3(aq) + CaCO 3(s) 2K + + CO Ca NO 3 - 2K + + CO Ca NO 3 -  CaCO 3(s) + K + + NO 3 -  CaCO 3(s) + K + + NO 3 - Just ignore coefficients when canceling Just ignore coefficients when canceling Ca ++ + CO 3 2-  CaCO 3(s) Ca ++ + CO 3 2-  CaCO 3(s) If it were unbalanced now you would balance it If it were unbalanced now you would balance it

Tip to make sure your answer is right Make sure you have the same atoms on each side of the equation Make sure you have the same atoms on each side of the equation If your final answer is something like If your final answer is something like K + + CO 3 2-  CaCO 3(s) K + + CO 3 2-  CaCO 3(s) It is wrong!!! It is wrong!!! Atoms don’t spontaneously change into other atoms (without a nuclear reaction) Atoms don’t spontaneously change into other atoms (without a nuclear reaction)

more K 2 C 2 O 4(aq) + CuNO 3 ( aq)  KNO 3(aq) + Cu 2 C 2 O 4(s) K 2 C 2 O 4(aq) + CuNO 3 ( aq)  KNO 3(aq) + Cu 2 C 2 O 4(s) Pb(ClO 3 ) 4(aq) + NiCl 2( aq)  Ni(ClO 3 ) 2(aq) + PbCl 4 (s) Pb(ClO 3 ) 4(aq) + NiCl 2( aq)  Ni(ClO 3 ) 2(aq) + PbCl 4 (s)

Homework Write the net ionic equation for the following Write the net ionic equation for the following Na 3 PO 4(aq) + Ba(NO 3 ) 2(aq)  NaNO 3(aq) + Ba 3 (PO 4 ) 2(s) Na 3 PO 4(aq) + Ba(NO 3 ) 2(aq)  NaNO 3(aq) + Ba 3 (PO 4 ) 2(s)