CHEM 101 1st Edition Lecture 7Overview of Lecture 6 I. Formula and Molecular WeightII. Limiting Reactants III. Theoretical YieldsLecture 7I. Aqueous Reactions and Stoichiometry II. Properties of Aqueous SolutionsIII. Electrolyte Properties IV. Precipitation ReactionsV. Soluble and Insoluble Compounds VI. Full and Net Ionic Equations*note: this is chapter 4 which will NOT be on the first exam*Aqueous Reactions - Solution – a homogeneous mixture of 2 or more substances - Solvent – substance present in the greatest quantityo Water us the solvent in aqueous solutions- Solute – substance dissolved in solventGeneral Properties of Aqueous Solutions- When an ionic compound dissolves in water it dissociates into its component ions. The dissolved ions are surrounded by H2O molecules o Example: NaCl (s)  Na+ (aq) + Cl – (aq)- Not all ionic compounds are dissolvable in waterThese notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.o When an ionic compound containing a polyatomic ion is dissolved in water atomsin the polyatomic ion stay togethero Pb (NO3)2 (s)  Pb (aq) + 2 NO3 (aq)- When a molecular compound dissolves in water the molecules remain intact and are evenly dispersed throughout the water o CH3OH (l)  CH3OH (aq) - Some molecular compounds (weak acids) will partially dissociate when dissolved in watero HF (g) ↔ H (aq) + F (aq) Half arrows in both directions mean the reaction goes in both directionsElectrolyte Properties of Aqueous Solutions- Strong Electrolytes – substances that completely dissociate into ions when dissolved in water. The ions are able to move in solution to carry electrical current- Nonelectrolytes – substances that do not conduct electricity when dissolved in water. These include molecular compounds that do not dissociate into ions- Weak Electrolytes – substances that only weakly conduct electricity when dissolved in water. These are weak acids that only partially dissociate into ionsPrecipitation Reactions- Exchange reaction – a reaction in which the cations and anions of 2 ionic compounds switch with one anothero AB + CD  AD + CBo Sometimes exchange reactions are also referred to as metathesis reactions- Precipitation Reaction – an exchange reaction in which an insoluble compound is formedo Example: AgNO3 (aq) + NaCl (aq)  AgCl (s) + NaNO3 (aq)  AgCl is insoluble in water- For ionic compounds (aq) means the ions are completely dissociated from each other o Ag (aq) + NO3 (aq) + Na (aq) + Cl (aq)  AgCl (s) + Na (aq) + NO3 (aq) Notice that some ions appear in the same form on both sides of the equation. These are spectator ions and remain unchanged in the reactions. Spectator ions cancel out- Ag (aq) + Cl (aq)  AgCl (s)How do you know what compound (if any) precipitates in a chemical reaction?- Look at the anion - Soluble ionic compoundso NO3 – o CH3COO-o Cl- , Br- , I-  Except with Ag and/or Pbo SO42-  Except with Sr, Ba, Pb- Insoluble Ionic Compoundso S2- , OH- Except with alkali metal cations NH4, Ca, Sr, and Bao CO3 , PO4 Except with alkali metal cations and NH4- All common ionic compounds with alkali metal cations and NH4 are solublePredict what the solid product is in the following reaction and write the net ionic equationNaOH (aq) + Cd(NO3)2 (aq)  2NaNO3 (aq) + Cd(OH)2 (s)- Full ionic equationo 2Na (aq) + 2OH (aq) + Cd (aq) + 2NO3 (aq)  2Na (aq) + 2NO3 (aq) + Cd(OH2) (s) Cross out spectators- Net Ionic Equationo 2OH (aq) + Cd (aq)  Cd (OH2) (s)No reaction occurs if no insoluble compound is formed/if all ions are spectator