betweenKa for a Weak Acid and Kb for its Conjugate Base
The relationshipbetweenKa 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...
concentration of
0.121 moldm‐3 (pKb of ammonia is 4.75) [5]
(M04/H/1) What is the relationshipbetweenKa 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...
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...
A. The relationshipbetweenKa 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...
base. The relationshipbetween 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...
extreme pH values give different scanning curves. Comment on the relationshipbetween the color of the substance and the λmax
Color illustrates the approximate complementary relationshipbetween the wavelengths of light absorbed and the wavelengths transmitted or reflected.
2. What is the...
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...
solution, there must be a relationshipbetween 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...
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...
accurate in determining the pKa value for ethanoic acid.
This can be explained by the fact that there is an equal relationshipbetween 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...
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...
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...
, 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...
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...
, 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...
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 relationshipbetween the...
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...
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...