Based on pKas of glycine hydrochloride estimate the percentage
of molecules that are fully protonated in...
Based on pKas of glycine hydrochloride estimate the percentage
of molecules that are fully protonated in a solution with pH =
4.4
pKa1 = 2.35 ,pKa2 = 9.60 , MW = 111.6
Solutions
Expert Solution
Chloride ion being of no importance here, has been
omitted.
It can be seen from the pKa values that the first proton will
be lost from COOH group. So we shall do all calculations in
connection with the pKa values of carboxylic group.
Using data from the table below, estimate the percentage of
chlorocyclohexane molecules that have their
substituents in an axial orientation at room temperature.
Table 4.1 - http://imgur.com/ZLsHz5S,9ose7I0
Figure 4.12 - http://imgur.com/ZLsHz5S,9ose7I0#1
Imagine you have prepared a 25.0 mL sample of .100 M glycine
hydrochloride solution to use in a titration with NaOH.
a) Using your pKa1 value (2.38) and the Henderson-Hasselbach
equation, calculate the ratio of the concentrations of
([C2H5NO2]/[C2H6NO2+])
present at pH= 2.50 for glycine hydrochloride solution.
b) What volume of .100M NaOH would you have to add during the
titration to reach pH = 2.50?
The Kb for an amine is 2.105 × 10-5. What percentage of the
amine is protonated if the pH of a solution of the amine is 9.788?
(Assume that all OH– came from the reaction of B with H2O.)
The Kb for an amine is 8.695 × 10-5. What percentage of the
amine is protonated if the pH of a solution of the amine is 9.207?
(Assume that all OH– came from the reaction of B with H2O.)
Consider a solution of 0.0500 M isoleucine. If we call the fully
protonated form H2A+, find the pH of a solution of: (a) 0.0500 M
H2ACl, (b) 0.0500 M HA, and (c) 0.0500 M NaA. For the intermediate
form, HA, calculate the pH using any reasonable
approximations.
pKa1 = 2.31
pKa2 = 9.60
Consider a solution of 0.0500 M isoleucine. If we call the fully
protonated form H2A+, find the pH of a solution of: (a) 0.0500 M
H2ACl, (b) 0.0500 M HA, and (c) 0.0500 M NaA. For the intermediate
form, HA, calculate the pH using any reasonable approximations.
pKa1 = 2.318 pKa2 = 9.758
Estimate the time needed for a glycine molecule (see Table 13?4
in the textbook) to diffuse a distance of 29 ?m in water at 20 ?C
if its concentration varies over that distance from 1.05 mol/m3 to
0.43 mol/m3 Compare this "speed" to its rms (thermal) speed. The
molecular mass of glycine is about 75 u
i) Based on the molecular geometry of the molecules from
question 1, circle the following molecules that are nonpolar:
BeF2
KrF2
KrF4
NH4+
H2Te
ii) Write the bond-line formulas for the following
straight-chain alkanes.
(a) Hexane (b) Octane