Chem 102 1st Edition Lecture 7 Outline of Last Lecture I. Equilibrium ConstantA. PressureB. MagnitudeC. CalculatingD. Predicting Direction E. Microscopic ReversibilityII. Le Chatelier’s PrincipleA. Volume and PressureB. TemperatureC. CatalystsOutline of Current Lecture I. Acid and Base Equilibrium A. Bronsted- Lowry Acids and BasesB. pH ScaleC. Strong Acids/ BasesCurrent Lecture. Acid and Base Equilibrium- acids=sour, bases=bitter -Arrhenius- acids increase [H+] in solution and bases increase [OH-] in solution… acid + base salt + water, the problem is this limits us to aqueous solutions. A. Bronsted-Lowry- acid donates H+ and base accepts H+, these cases do not need to have an OH-, water can either behave as an acid or a base, it is amphoteric.-Conjugate base- whatever of the acid is left after the proton is donated. -Conjugate acid- whatever of the base remains after it accepts theproton. -Conjugate acid-base pairs differ by only one proton. -The stronger the acid the weaker the conjugate base. -H+ is the strongest acid that can exist in equilibrium in aqueous solutions, while OH- is the strongest base. Any acid or base that is These 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.stronger reacts stoichiometrically to produce H+ and OH-. -The conjugate base of a strong acid has negligible acid-base properties, vice versa, conjugate acid of a strong base has negligible acid-base properties. B. pH Scale-in most solutions [H+(aq)] is quite small. -pH= -log[H+] or pH= -log[H3O+]-Acids have a pH less than 7, bases have a pH greater than 7. -The higher the pH, the lower the pOH, the more basic the solution. -Other “p” scales can be used. Such as, pX= -logX-The most accurate way to measure pH is by using a pH meter. -Indicators- certain dyes that change color as pH changes. Indicators are not as precise as pH meters. Most indicators are red in acidic solutions.C. Strong Acids/Bases -STRONG ACIDS- HCl, HBr, HI, HNO3, HClO3, HClO4, H2SO4. Strong acids are strong electrolytes. All strong acids iodize completely in solution. In solutions the strong acid is usually the only source of H+, therefore the pH of the solution is the initial molarity of the acid. -STRONG BASES- NaOH, KOH, Ca(OH)2. Most ionic hydroxides are strong bases. -Strong bases are strong electrolytes and dissociate completely in solution. -The pOH of a strong base is given by the initial molarity of the base. In order for a hydroxide to be a base, it must be
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