• Acid-Base Calculations
    between Ka for a Weak Acid and Kb for its Conjugate Base The relationship between Ka for a weak acid HA and Kb for its conjugate base A– is Ka(HA) Kb(A–) = Kw = 1.0 x 10-14 (12) If we define pKa = - log10(Ka) and pKb = - log10(Kb), the logarithmic form of Eq(12) is pKa(HA) + pKb(A...
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  • Acids and Bases Exercises
     concentration of  0.121 moldm‐3 (pKb of ammonia is 4.75)                              [5]    (M04/H/1) What is the relationship between Ka and pka?  (N03/H)   a)  Calculate the Ka value of methanoic acid, HCOOH, using table 15 in the Data  Booklet.                [1]  b)  Based on its Ka...
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  • Chemistry 151 Weak Acid Titration
    sample and the weight of the sample we can determine the molar mass of that sample. Molar Mass is a unit with sub-units(g/mol) so by dividing the mass of the sample by the titrated moles we can determine the molar mass. To determine Ka values the equation pKa =-log Ka, along with the relationship...
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  • Determination of Ka for a weak Acdi
    A. The relationship between Ka and pKa is that Ka is the equilibrium constant for the dissociation of a weak acid and pKa is the half-equivalence point where pH=pKa. In addition to the pH, Ka is an indication of an acids strength; pKa = - log Ka. B. The potential sources for errors...
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  • titration acid base
    base. The relationship between these two ions revolves around the auto-ionization reaction of water(1): 2H2O (l)  H3O+ (aq) + OH- (aq) This reaction is described by the equilibrium constant Kw, 1.01 x 10-14, at 25o C. The auto-ionization equilibrium couples with the equilibrium between the...
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  • POSTLAB
    extreme pH values give different scanning curves. Comment on the relationship between the color of the substance and the λmax Color illustrates the approximate complementary relationship between the wavelengths of light absorbed and the wavelengths transmitted or reflected. 2. What is the...
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  • Acid and Bases Ib
    often expressed as a pKa, the relationship being similar to that between [H+] and pH: pKa = – log Ka (hence Ka = 10-pKa) Solution If pH = 5.00, then 2 +] = [A–] = 1.00 × 10–5 mol dm–3. [H x Ka = ____ a–x The Ka of ethanoic acid, for example, is 1.74 × 10–5 mol dm–3 at 298 K, so that its...
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  • Acids
    solution, there must be a relationship between pH and the pKa of a weak acid. This relationship is given by the Henderson–Hasselbalch equation: pH= pKa   +   log  [base] [acid] Where “base” represents the conjugate base, and “acid” the conjugate acid, of a...
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  • Chemical Reactions
    relationship in the following two equilibria: Conjugate Acids NH4(+) H2O NH4(+) H3O(+) Conjugate Bases NH3 OH(–) NH3 H2O Acid-Base Reaction K pK NH3 + H2O NH4(+) + OH(–) Kb = 1.8*10-5 pKb = 4.74 NH4(+) + H2O H3O(+) + NH3 Ka = 5.5*10-10 pKa = 9.25 Tables of pKa values for...
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  • Chem 3418 Organic Chemistry Laboratory I Acid Base Review
    % − ( $ [A ] ' Ka = # [HA] & −log[H 3O+ ] = −log[K a ] − log% − ( $ [A ] ' # [HA] & pH = pKa − log% − ( $ [A ] ' # [A − ] & pH = pKa + log% ( $ [HA] ' The Henderson-Hasselbach equation shows the relationship between the pH of an aqueous solution, the pKa of the organic solute, and the relative...
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  • a2 chemistry
    calculate precisely what happens. In general, for a reversible reaction between a moles of substance A, and b moles of substance B etc: a A + b B c C + d D when the system has come to equilibrium, the ratio given by Kc will be constant: Kc = where [C] means concentration at...
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  • Determine Pka of Ethanoic Acid
    accurate in determining the pKa value for ethanoic acid. This can be explained by the fact that there is an equal relationship between the pH and pKa values, the accuracy of which is solemnly dependent on the titration curve plotted. “Method 1” involves determining other variables (e.g. H+ or Ka...
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  • Biochem Review
    the reaction reaches equilibrium, which happens very quickly, the acid dissociation constant is equal to the concentration of the products divided by the concentration of the reactants. o Because Ka values are numerically small, they are placed in a logarithmic scale. pKa = -log Ka A pH...
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  • Unit Plan on Acids and Bases
    dissociation ▪ Give examples of conjugate acid/base pair ▪ Introduce Ka, and pka ▪ Show that dilution favors the dissociation of weak acid or weak base ▪ Model calculating pH of a weak acid or weak base ▪ Explain relation between pH and pKa ▪ Model using the gamma rule to...
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  • Lab of Acid Base
    , make sure to record all your observations in your notebook. Most importantly, have fun. This is what chemistry is all about. — MAH Unknown Acids, Indicators, and Buffers page 2 The pKa of an Unknown Acid-Base Indicator Your group will be assigned a solution containing an unknown amount of...
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  • The Determination of Acid Constant Ka
    reactions; b) to review the basic lab procedure of a titration and introduce the student to the concept of a primary standard and the process of standardization. From my graph my equivalence point was PH=8.80, volume is 15 ml , pka=4.80, ka=1.58 × 10-5 Introduction Acids dissolve in water...
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  • Sceince
    , use this formula to find the Ka: pKa = -log10 Ka or inversely Ka = 10-pKa OK -- now how do we solve? To do this, we must set up what is sometimes called an "ICE" chart, for Initial-Change-End. Because of the formating constraints, it will be hard to show that here correctly, but I will...
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  • Package
    Pharmaceuticals H2 N H N O O O O Tamiflu 8) (8 pts) Working out the configurations of the chiral centers (i.e. R or S) will help in the following questions. (Klein Chapter 5) a. Convert the following “wedge-dash” depiction into a Fischer projection. b. What is the relationship between the...
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  • subi
    constant for the conjugate acid of the base. So we start with the protonated base and write the reaction equation for dissociation of the protonated base (conjugate acid of the base) The larger the pKa value, the stronger the base. We would expect that the acid dissociation constant, Ka , for the...
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  • pH Titration
    drawing tool to add these. Table 3. Ka data. (5 pts) For both Ka’s, include the volume used for graphical Ka determination, pKa determined graphically, corresponding Ka, and true (“literature”) values for pKa and Ka. Include Ka1 calculated from the initial pH of cola and the initial...
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