Net Ionic Equations - Continuation of Chapter 7

Net Ionic Equations - Continuation of Chapter 7

Molecular Equations - all reactants and products are shown as neutral compounds.

Total Ionic Equations - all cations and anions in solution are shown separately (all soluble compounds listed as ions).

Net Ionic Equations - total ionic equation with spectator ions cancelled.

Spectator ions - ions that are in an identical state on both sides of an equation (note directly involved in the reaction.

Examples:

Molecular: AgNO₃(aq) + NaCl(aq) ® AgCl(s) + NaNO₃(aq)

Total Ionic: Ag⁺(aq) + NO₃^-(Aq) + Na⁺(aq) + Cl^-(aq) ® AgCl(s) + Na⁺(aq) + NO₃^-(aq)

Net Ionic: Ag⁺(aq) + Cl^-(aq) ® AgCl(s)

(NO₃^-(aq) and Na⁺(aq) appear on both sides of the equation, they are spectators).

Predicting Double Replacement Reactions (Solubility):

Solubility Rules - table 7-3 and 7-4

Anion	Solubility	Exceptions
Cl^-, Br^-, I^-	Soluble	with Ag⁺, Hg₂^2+, and Pb²⁺ (PbCl₂ and PbBr₂ slightly soluble)
NO₃^-,ClO₃^-, ClO₄^-, C₂H₃O₂^-	Soluble	(KClO₄ and AgC₂H₃O₂ slightly soluble)
SO₄^2-	Soluble	Pb²⁺, Ba²⁺, Sr²⁺ (Ca²⁺ and Ag⁺ slightly soluble)
CO₃^2-, SO₃^2-, PO₄^3-	Insoluble	Group IA and NH4+
S^2-	Insoluble	Group IA and IIA and NH4+
OH^-	Insoluble	Group IA, Ba²⁺, Sr²⁺and NH₄⁺ (Ca(OH)₂ is slightly soluble)
O^2-	Insoluble	Group IA, Ca²⁺, Ba²⁺and Sr²⁺

Examples:

Na₂CO₃(aq) + CaCl₂(aq) ® ?

Are they soluble? NaCl - Yes

CaCO₃ - No

Na₂CO₃(aq) + CaCl₂(aq) ® NaCl(aq) + CaCO₃(aq)

Then Balance:

Na₂CO₃(aq) + CaCl₂(aq) ® 2NaCl(aq) + CaCO₃(s)

TIE: 2Na⁺+ CO₃^2-(aq) + Ca²⁺(aq) + 2Cl^-(aq) ® 2Na⁺+ 2Cl^-(aq) + CaCO₃(s)

NIE: CO₃^2-(aq) + Ca²⁺(aq) ® CaCO₃(s)

States are Essential!