CHEM 111 1st Edition Lecture 6Sugar in water: Solvent=waterSolute=sugarSolutionsC2H5OH(l)−−−(H2O)−→ C2H5OH(aq)C6H12O6(s)−−−(H2O)−→C6H12O6(aq)Molecular solids fall apart become solvated (hydrated in H2O)Some compounds dissolve and dissociate somewhat or fully−¿(aq)+¿(aq)+C l¿KCl(s)−→ K¿−¿(aq)+¿(aq)+N O3¿HN O3(aq)−→H¿Solvation: polar water molecules orient themselves to maximize + - interactionsSolubility’s:-Need empirical data and rulesGeneral rules (with water as solvent!):1. Network solids are usually insoluble in water2. Metals are insoluble or react (corrode) slowly or rapidly. Ca or Na in H2O3. Ionic compoundsThere is a range of solubility’s-not just soluble or insolubleHgS: extremely insoluble in waterNaCl: extremely soluble in waterCa(OH)2 –somewhere in-betweenMolecular SubstancesC8H18∧CC l4 INSOLUBLEn ×butyl alcohol SOMEWHAT SOLUBLEEthanol and methanol MISCIBLE IN ALL PROPORTIONSHN O3∧H2S O4 MISCIBLE IN ALL PROPRTIONSElectrolytesAn electrolyte is any substance that increase the number of ions in water, when the substance is dissolved in water Strong vs. WeakA strong electrolyte is one which, when dissolved in water, etheir already is or becomes almost entirely ions in a solutionNaCl, CaCl2, KNO3, Na2SO4, NaOH, ect.A weak electrolyte is one which when dissolved in water, results in RELATIVELY few ions, i.e., it is mostly Unionized and un-dissociatedALL WEAK ACIDS AND WEAK BASES ARE IN THIS CATEGORY!Acids and BasesSimplest (Arrhenius) definitions:Acid: increases +¿(aq)H¿ when dissolved in H2Oe.g. HClBase: increase −¿(aq)when dissolved∈H2OO H¿e.g. KOHAcids and BasesImproved (Bronsted-Lowry) definitions:Acid: +¿(aq)donorH¿ e.g. HClBase: +¿ acceptorH¿e.g. +¿(aq)+H2O+¿−→ K¿KOH(aq)+H¿Bases take protons (H+ ions) from Acids! Strong acids are strong electrolytes that are acidsStrong bases are strong electrolytes that are basesStrong acids: MEMORIZE THESEHN O3H2S O4HClO4HCl HBr HIStrong Bases:LiOH NaOH KOH RbOH CsOH Ca(OH)2Sr(OH)2Ba(OH)2These are all ionic and soluble, or at least sparingly soluble, in the case of Ca(OH)2Weak acids: Many thousands!Weak bases: Many thousands!Acid Base ReactionsHN O3(aq)+NaOH(aq)−−−→ NaN O3(aq)+HO HQuestion: What is the net ionic equation?NO3- and Na+ aren’t doing anything-they started in solution (Na+(aq)) and they ended In solution (Na+(aq))Answer: −¿(aq)−−−→ H2O+¿(aq)+O