5. Acids and Bases( Chapter 15, 16.1--16.4) 5. 1. The Bronsted-Lowry definitions(H, OH transfer) (a). Strong acid(base)and Weak acid(base) (b). Conjugated acid-base pair Note in each acid-base reactions, there are two conjugated acid-base pairs (c). Poly-protic acid(base), and amphoteric substance 5.2. Lewis acid-base definition (transfer of lone pair electrons to an empty orbital) 5.3. lon pro ater,Kw=[H3O]x [OH-]=10-4(@25C (a). Kw is a constant in all aqueous solution(under a constant temperature) (b).[H3O]>10M→ acidic;田H3O=107M→ neutral;田H3O+<10M→ basic (c). pH=-logIo [H30*]: pOH=-log1o [OH]; pH pOH= 14 (d). Definition of Ka, Kb Calculate the Ka, Kb of their conjugated acid/base 5.4. Calculation of H3 in acid solution(s Every calculation is indeed based on"Initial-Change-Equilibrium"for setting up a quadratic equation of equilibrium constant (a). strong acid only Let the strong acid dissociate completely first, and then see whether thewater dissociation matters, i.e. whether [H3O*]from the strong acid>10-5M? (b). weak acid only Consider the Kal only( for poly-protic acid) If Cacid/Ka>100>[H30]=v(Cacid X Ka) If Cacid/Ka< 100> need to solve the quadratic equation (c). one strong acid+ one weak acid Let the strong acid dissociate completely first, and then setup the" ICE equation of the weak acid's dissociation (d). one weak acid its conjugated base(it is a buffer Ina buffer [H30]=Ka(Cacid/Cbase) (e). one acid one bas Let the acid-base reaction go into completion first. (Need to find out the limiting reactants! Then the remaining species will belong to one of the 5.5. Calculation of oH-l in base solution(s) 5.6. Hydrolysis of salt (a). How to quickly judge whether a salt is acidic, neutral or basic (b). Calculate the pH value of a salt solutio 5.7. Buffer solutions Note for a good buffer, its acid/base ratio should be 0. 1-10 5.8.Tt (a). Titration curve: use a strong base to titrate a strong acid (b). Titration curve: use a strong base to titrate a weak acid5．Acids and Bases (Chapter 15, 16.1—16.4) 5.1．The Bronsted-Lowry definitions(— H+ , OH￾transfer) (a)．Strong acid (base) and Weak acid (base) (b)．Conjugated acid-base pair  Note in each acid-base reactions, there are two conjugated acid-base pairs (c)．Poly-protic acid (base), and amphoteric substance 5.2．Lewis acid-base definition (— transfer of lone pair electrons to an empty orbital) 5.3．Ion product of water, Kw = [H3O+ ] × [OH- ] = 10-14 (@ 25 oC) (a)．Kw is a constant in all aqueous solution (under a constant temperature) (b)．[H3O+ ] > 10-7 M → acidic; [H3O+ ] = 10-7 M → neutral; [H3O+ ] < 10-7 M → basic (c)．pH = – log10 [H3O+ ]; pOH = – log10 [OH- ]; pH + pOH = 14 (d)．Definition of Ka, Kb.  Calculate the Ka, Kb of their conjugated acid/base 5.4．Calculation of [H3O+ ] in acid solution(s)  Every calculation is indeed based on “Initial–Change–Equilibrium” for setting up a quadratic equation of equilibrium constant. (a)．strong acid only  Let the strong acid dissociate completely first, and then see whether thewater dissociation matters, i.e. whether [H3O+ ] from the strong acid > 10-5 M? (b)．weak acid only  Consider the Ka1 only (for poly-protic acid)  If Cacid/Ka > 100 → [H3O+ ] = √(Cacid × Ka)  If Cacid/Ka ≤ 100 → need to solve the quadratic equation (c)．one strong acid + one weak acid  Let the strong acid dissociate completely first, and then setup the “ICE” equation of the weak acid’s dissociation. (d)．one weak acid + its conjugated base (it is a buffer!)  In a buffer: [H3O+ ] = Ka × (Cacid / Cbase) (e)．one acid + one base  Let the acid-base reaction go into completion first. (Need to find out the limiting reactants!) Then the remaining species will belong to one of the previous categories. 5.5．Calculation of [OH- ] in base solution(s) 5.6．Hydrolysis of salt (a)．How to quickly judge whether a salt is acidic, neutral or basic (b)．Calculate the pH value of a salt solution 5.7．Buffer solutions  Note for a good buffer, its acid/base ratio should be 0.1~10. 5.8．Titration (a)．Titration curve: use a strong base to titrate a strong acid (b)．Titration curve: use a strong base to titrate a weak acid