L37S07_Polyprotic Acids, Amino Acids 04-20-07

L37S07_Polyprotic Acids, Amino Acids 04-20-07 - Chem 1A L...

Info icon This preview shows page 1. Sign up to view the full content.

View Full Document Right Arrow Icon
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: Chem 1A L 37: "Polyprotic Acids, Amino Acids " pH Titration of a Weak Acid by a Strong Base D C B AE.P. A HA Summary TITRATION O + Ac HAc + H O H WEAK-ACID BASE OH0.1 - x 2 Region A : 0.1 M HAc 3 + - x x Expect: 1.0 < pH < 7.0 HA/AHA/ Buffer acid HA + OH- base H2O + A- acid base Assume 0.1-x ? 0.1 0.1x2 = Ka = 1.76 x 10-5 0.1- x pH = 2.88 0.1x2 = 0.1 Ka x = 1.33x10-3 L29-6 + OHA.Pines,M.Kubinec,UCB L29-4 A.Pines,M.Kubinec,UCB Region C : 0.1 M AcAc - + H2O 0.1 - x Region B : [HA] ~ [HA] pH Buffer [A-] HAc +OHx Expect: x 7.0 < pH < 13.0 x2 = Kb = 5.68 x 10-10 0.1- x 0.1x2 = 0.1 Kb A.Pines,M.Kubinec,UCB Assume 0.1-x ? 0.1 0.1pH = 8.88 [HA] = [A-] x = 7.5x10-6 L29-8 A.Pines,M.Kubinec,UCB E.P. A.Pines,M.Kubinec,UBC HA + OH- H2O + AH2O + HA A- + H3O+ K >> 1 + L37-1 OHL30-4 ChemQuiz 36.2 Shown in yellow is the titration of HNO3 per mole KOH. Which is KOH. the correct curve for x10 dilution of HNO3? 1) A.Pines,M.Kubinec,UCB H2O HNO3 2) mol OHmol OH- 3) mol OHL37-2 ChemQuiz 36.3 Shown is in yellow the titration of HAc per mole KOH. Which is the KOH. correct curve for x10 dilution of HAc? HAc? 1) A.Pines,M.Kubinec,UCB H2O HAc 2) mol OHmol OH- 3) mol OHL37-4 A.Pines,M.Kubinec,UCB 1 Chem 1A L 37: "Polyprotic Acids, Amino Acids " PolyProtic Acids/Blood Buffer Summary Blood pH Stats: pH PCO = 40 torr 2 pKa2 pKa1 +OH A.Pines,M.Kubinec,UBC [CO2] = 1.2 mM [CO2] = [H2CO3] Carbonic Anhydrase Kidneys Lungs Henry's Law [HCO3-] = 24 mM L30-12 A.Pines,M.Kubinec,UCB L37-6 PolyProtic Acids: Indicators Thymol Blue (H2Thy) (H Thy) HThypH pKa2 Thy-2 + H+ pKa2 = 8.8 pKa1 H2Thy HThy- + H+ +OH- pKa1 = 2.0 A.Pines,M.Kubinec,UCB L37-7 PolyProtic Acids H2CO3 pH H3PO4 H2SO4 trend: pKa1 < pKa2 < pKa3 pKa2 pKa1 HCO3H2CO3 +OH- CO3-2 + H3O+ pKa2 = 10.2 HCO3- + H3O+ pKa1 = 6.1 A.Pines,M.Kubinec,UCB L37-8 A.Pines,M.Kubinec,UCB 2 Chem 1A L 37: "Polyprotic Acids, Amino Acids " ChemQuiz 37.1 Which carbonate species is present in the highest concentration at pH 7 ? pKa2 pKa1 1) H2CO3 A.Pines,M.Kubinec,UCB 2) HCO3 -1 3) CO3 -2 L37-9 PolyProtic Acids/Blood Buffer Blood pH Stats: pH PCO = 40 torr 2 pKa2 pKa1 +OHA.Pines,M.Kubinec,UCB [CO2] = 1.2 mM [CO2] = [H2CO3] Carbonic Anhydrase Kidneys Lungs Henry's Law Henry' [HCO3-] = 24 mM L37-11 PolyProtic Acids/Blood Buffer Blood pH Stats: Henry's Law Henry' 24] [[24] 3-] HCO pH = pKa + log 6.1 [H2CO3] [CO2] = 1.2 mM [1.2] 1.2] [CO2] = [H2CO3] [H Carbonic Anhydrase pH = 7.4 [HCO3-] = 24 mM Kidneys PCO = 40 torr 2 Lungs A.Pines,M.Kubinec,UCB L37-12 A.Pines,M.Kubinec,UCB 3 Chem 1A L 37: "Polyprotic Acids, Amino Acids " 9.0 Amino Acid pKa's C C C C +N -O O C C + N 9.1 pH = 7.0 10.5 10.1 C C C C C C O 2.2 Lysine O +N 2.2 C C C - O Tyrosine A.Pines,M.Kubinec,UCB L37-13 Amino Acid pKa's +N 2.0 O 10 O C C C 3.9 O 9.2 N N C C C C pH = 7.0 C O - Aspartic Acid O O + C N N C C C N N 6.0 C C A.Pines,M.Kubinec,UCB 1.8 O O Histidine L37-14 ChemQuiz 37.2 Solution pKa: pKa= 9.0 pH < pKa: acid form pH 5.0 - N + + C O C C S pH < pKa: acid form pKa: pKa= 8.0 pH > pKa: base form pKa: pKa= 2.2 1) + 1 A.Pines,M.Kubinec,UCB 2) 0 3) -1 L37-16 A.Pines,M.Kubinec,UCB 4 Chem 1A L 37: "Polyprotic Acids, Amino Acids " Lecture complete A.Pines,M.Kubinec,UCB L37-17 A.Pines,M.Kubinec,UCB 5 ...
View Full Document

{[ snackBarMessage ]}

What students are saying

  • Left Quote Icon

    As a current student on this bumpy collegiate pathway, I stumbled upon Course Hero, where I can find study resources for nearly all my courses, get online help from tutors 24/7, and even share my old projects, papers, and lecture notes with other students.

    Student Picture

    Kiran Temple University Fox School of Business ‘17, Course Hero Intern

  • Left Quote Icon

    I cannot even describe how much Course Hero helped me this summer. It’s truly become something I can always rely on and help me. In the end, I was not only able to survive summer classes, but I was able to thrive thanks to Course Hero.

    Student Picture

    Dana University of Pennsylvania ‘17, Course Hero Intern

  • Left Quote Icon

    The ability to access any university’s resources through Course Hero proved invaluable in my case. I was behind on Tulane coursework and actually used UCLA’s materials to help me move forward and get everything together on time.

    Student Picture

    Jill Tulane University ‘16, Course Hero Intern