Part I: Sections 1-4

An Ionic Compound, CuCl 2, in Water CCR, page 177

How do we know ions are present in aqueous solutions? The solutions conduct electricity! They are called ELECTROLYTES HCl, CuCl 2, and NaCl are strong electrolytes. They dissociate completely (or nearly so) into ions. Aqueous Solutions

Acetic acid ionizes only to a small extent, so it is a weak electrolyte. CH 3 CO 2 H(aq) ---> CH 3 CO 2 - (aq) + H + (aq)

Aqueous Solutions Some compounds dissolve in water but do not conduct electricity. They are called nonelectrolytes. Examples include: sugarethanol ethylene glycol Examples include: sugarethanol ethylene glycol

KISS Rules – Keep it Simple Solubility Rules #1 – Soluble Cations: sodium, potassium, and ammonium are always soluble #2 – Soluble Anions – nitrate, acetate, chlorate, perchlorate are always soluble #3 – Soluble Anions – chloride, bromide, iodide are soluble EXCEPT with the SILVER GROUP – silver, mercury and lead #4 – Soluble Anions – sulfate is soluble EXCEPT with the Silver Group or with strontium or barium #5 – EVERYTHING ELSE IS INSOLUBLE

Net Ionic Equations Mg(s) + 2 HCl(aq) --> H 2 (g) + MgCl 2 (aq) We really should write Mg(s) + 2 H + (aq) + 2 Cl - (aq) ---> H 2 (g) + Mg 2+ (aq) + 2 Cl - (aq) The two Cl - ions are SPECTATOR IONS — they do not participate. Could have used NO 3 -.

Net Ionic Equations Mg(s) + 2 HCl(aq) --> H 2 (g) + MgCl 2 (aq) Mg(s) + 2 H + (aq) + 2 Cl - (aq) ---> H 2 (g) + Mg 2+ (aq) + 2 Cl - (aq) We leave the spectator ions out — Mg(s) + 2 H + (aq) ---> H 2 (g) + Mg 2+ (aq) NET IONIC EQUATION to give the NET IONIC EQUATION

Precipitation Reactions The “driving force” is the formation of an insoluble compound — a precipitate. Pb(NO 3 ) 2 (aq) + 2 KI(aq) -----> 2 KNO 3 (aq) + PbI 2 (s) 2 KNO 3 (aq) + PbI 2 (s) Net ionic equation Pb 2+ (aq) + 2 I - (aq) ---> PbI 2 (s)

What are the properties of acids and bases? pH taste litmus color Arrhenius definition pH taste feel litmus color Arrhenius definition

Acids ---> H + in water ACIDS HCl(aq) ---> H + (aq) + Cl - (aq) HCl is a strong acid Other strong acids include: HI, HBr, HNO 3, H 2 SO 4, HClO 4

ACIDS Nonmetal oxides can produce acids CO 2 (aq) + H 2 O ---> H 2 CO 3 (aq) SO 3 (aq) + H 2 O ---> H 2 SO 4 (aq) and can come from burning coal and oil.

Base ---> OH - in water BASES NaOH(aq) ---> Na + (aq) + OH - (aq) NaOH is a strong base Other strong bases include: LiOH and KOH

Ammonia, NH 3 Ammonia, NH 3 An Important Weak Base

BASES Metal oxides can produce bases CaO(s) + H 2 O --> Ca(OH) 2 (aq) CaO in water. Indicator shows solution is basic.

Acid-Base Reactions The “driving force” is the formation of water. The “driving force” is the formation of water. NaOH(aq) + HCl(aq) ---> NaCl(aq) + H 2 O(liq) Net ionic equation Net ionic equation OH - (aq) + H + (aq)---> H 2 O(liq) OH - (aq) + H + (aq)---> H 2 O(liq) This applies to ALL reactions of STRONG acids and bases. This applies to ALL reactions of STRONG acids and bases.

Acid-Base Reactions A-B reactions are sometimes called NEUTRALIZATIONS because the solution is neither acidic nor basic at the end. A-B reactions are sometimes called NEUTRALIZATIONS because the solution is neither acidic nor basic at the end. The other product of the A-B reaction is a SALT, MX. The other product of the A-B reaction is a SALT, MX. HX + MOH ---> MX + H 2 O HX + MOH ---> MX + H 2 O M n+ comes from base & X n- comes from acid M n+ comes from base & X n- comes from acid This is one way to make compounds! This is one way to make compounds!

Gas-Forming Reactions There are four important gas-forming reactions to learn: The formation of a GAS is the DRIVING FORCE in these reactions.