CHAPTER 6 STUDY GUIDEJULY 7, 2010AQUEOUS SOLUTIONS: ELECTROLYTES AND EXTENT OF IONIZATION aqueous solutions consist of a solute dissolved in water classification of solutes:1. non-electrolytes – solutes that:- do not conduct electricity in water because they do not form ions when dissolved in solution (ions conduct electricity in solution)- ionize slightly in water, typically 1–5%examples of non-electrolytes include:- C2H5OH  ethanolcontains only non-metalscontains no metals or polyatomic ionscannot produce ions in water- C6H12O6  glucose (blood sugar)contains only non-metalscannot produce ions in water- C12H22O11  sucrose (table sugar)contains only non-metalscannot produce ions in water2. strong electrolytes – solutes that:- conduct electricity extremely well in dilute aqueous solutions because they form ions when dissolved in solution (ions conduct electricity in solutions)- ionize essentially 100% in waterexamples of strong electrolytes include:- strong soluble acids, such as HCl, HNO3, etc.- strong soluble bases, such as NaOH, KOH, etc.- soluble ionic compounds, such as NaCl, KBr, etc.3. weak electrolytes – solutes that:- conduct electricity poorly in dilute aqueous solutions because they form very few ions when dissolved in solution (ions conduct electricity in solutions)examples of weak electrolytes include:- CH3COOH  acetic acid (vinegar)- (COOH)2  oxalic acid- weak bases, such as NH3, Fe(OH)3, etc.- some soluble covalent salts (which ionize in water much less than 100%) the electrolyte chartELECTROLYTESstrong electrolytes weak electrolytes non-electrolytes- strong bases- strong acids- water soluble salts- weak acids- weak bases- covalent compounds(non-metals)- insoluble saltsAQUEOUS SOLUTIONS: STRONG AND WEAK ACIDS acids – substances that generate hydrogen ions (H+ or H3O+) in aqueous solutions strong acids – ionize 100% in water (only ions are produced!)- common strong acids and their anions *know this list!* (all others are weak acids!)STRONG ACIDS ANIONSformula name formula name1CHAPTER 6 STUDY GUIDEJULY 7, 2010HCl hydrochloric acid Cl-chloride ionHBr hydrobromic acid Br-bromide ionHI hydroiodic acid I-iodide ionHNO3nitric acid NO3-nitrate ionHClO4perchloric acid ClO4-perchlorate ionHClO3chloric acid ClO3-chlorate ionH2SO4sulfuric acid HSO4-hydrogen sulfate ionSO42-sulfate ion weak acids – ionize significantly less than 100% in water (typically ionize about 1–5%)- common weak acids and their anions *do not need to memorize these for the test!*WEAK ACIDS ANIONSformula name formula nameHF hydrofluoric acid F-fluoride ionCH3COOH acetic acid (vinegar)CH3COO-acetate ionHCN hydrocyanic acid CN-cyanide ionHNO2nitrous acid NO2-nitrite ionH2CO3carbonic acid (soda water)HCO3-hydrogen carbonate ionCO32-carbonate ionH2SO3sulfurous acid HSO3-hydrogen sulfite ionSO32-sulfite ionH3PO4phosphoric acid H2PO4-dihydrogen phosphate ionHPO42-hydrogen phosphate ionPO43-phosphate ion(COOH)2oxalic acid H(COO)2-hydrogen oxalateion(COO)22-oxalate ion the formulas for inorganic (mineral) acids are usually written with the H first- examples include: HCl, HBr, HCN, etc.- HCl(g)  H+(aq) + Cl-(aq)- HCN(g)  H+(aq) + CN-(aq) organic acids contain the carboxyl (-COOH) group- nearly all organic acids are weak- one example is CH3COOH(l)  CH3COO-(aq) + H+(aq)AQUEOUS SOLUTIONS: REVERSIBLE REACTIONS a double arrow () indicates that the reaction is reversible (basically, it occurs in both directions) weak electrolytes ionize only slightly (and reversibly) in dilute aqueous solutions- all weak inorganic acids ionize in reversible reactions and establish chemical equilibrium; this is why they ionize less than 100%AQUEOUS SOLUTIONS: STRONG BASES, INSOLUBLE BASES, AND WEAK BASES bases – substances that produce hydroxide ions (OH-) in aqueous solutions strong bases – dissociate 100% in water (only ions are produced!)- common strong bases *know this list!* (all others are weak bases!)2CHAPTER 6 STUDY GUIDEJULY 7, 2010STRONG BASES – GROUP 1A STRONG BASES – GROUP 2Aformula name formula nameLiOH lithium hydroxideNaOH sodium hydroxideKOH potassium hydroxideCa(OH)2calcium hydroxideRbOH rubidium hydroxideSr(OH)2strontium hydroxideCsOH cesium hydroxideBa(OH)2barium hydroxide insoluble or sparingly soluble bases - ionic compounds that are insoluble in water are not very basic- most transition metal hydroxides are insoluble in water *do not need to memorize!*INSOLUBLE BASESformula nameCu(OH)2copper(II) hydroxideFe(OH)2iron(II) hydroxideFe(OH)3iron(III) hydroxideZn(OH)2zinc hydroxideMg(OH)2magnesium hydroxide weak bases – often covalent compounds that ionize slightly (1–5%) in water- ammonia (NH3) is a common weak baseNH3 + H2O  NH4+ + OH-- organic amines are similar to ammonia in that they are weak basesCH3NH2 + H2O  CH3NH3+ + OH-CH3NHCH3 + H2O  CH3NH2+CH3 + OH-- the carbonate (CO32-) and bicarbonate (HCO3-) ions are weak basesHCO3- + H2O  CO2 + OH-CO32- + H2O  CO2 + 2OH-AQUEOUS SOLUTIONS: SOLUBILITY RULES the solubility rules *know these rules!*1. common inorganic acids and low-molecular-weight organic acids are water-soluble2. all common compounds of the group 1A metal ions (Li+, Na+, K+, Rb+, Cs+) and the ammonium ion (NH4+) are water-soluble3. common nitrates (NO3-), acetates (CH3COO-), chlorates (ClO3-), and perchlorates (ClO4-) are water-soluble4. common chlorides (Cl-) are water-solubleexceptions: AgCl, Hg2Cl2, and PbCl2  these are insolublecommon bromides (Br-) and iodides (I-) behave similarly to chlorides (Cl-); as these halides (Cl-, Br-, and I-) increase in size, the solubilities of their slightly soluble compounds decrease[no exceptions listed]common fluorides (F-) are water-soluble3CHAPTER 6 STUDY GUIDEJULY 7, 2010exceptions: MgF2, CaF2, SrF2, BaF2, and PbF2  these are insoluble5. common sulfates (SO42-) are water-solubleexceptions: PbSO4, BaSO4, and HgSO4  these are insolublemoderately soluble: CaSO4, SrSO4, and Ag2SO4  these are moderately soluble6. common metal hydroxides (OH-) are insolubleexceptions: those of the group 1A metals (LiOH, NaOH, KOH, RbOH, and CsOH) and the heavier members of the group 2A metals, beginning with Ca(OH)2  these are soluble7. common carbonates (CO32-), phosphates (PO43-), and arsenates (AsO43-) are insolubleexceptions: those of the group 1A metals and NH4+  these are solublemoderately soluble: BaCO3 and MgCO3 