Calculate the equilibrium concentration of the nonionized bases and all ions in a solution that is 0.25 M in CH 3 NH 2 and 0.10 M in C 5 H 5 N ( K b = 1.7 × 10 − 9 ) .
Calculate the equilibrium concentration of the nonionized bases and all ions in a solution that is 0.25 M in CH 3 NH 2 and 0.10 M in C 5 H 5 N ( K b = 1.7 × 10 − 9 ) .
Calculate the equilibrium concentration of the nonionized bases and all ions in a solution that is 0.25 M in CH3NH2 and 0.10 M in C5H5N
(
K
b
=
1.7
×
10
−
9
)
.
--
14:40 A
Candidate Identification
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13. The compound 1-bromo-hex-2-ene
reacts with methanol to form two
products. About this reaction, mark the
correct statement:
OCH3
CH3OH
Br
OCH3 +
+ HBr
A
B
A) The two products formed will have
the same percentage of formation.
B) Product B will be formed by SN1
substitution reaction with the formation
of an allylic carbocation.
C) Product A will be formed by SN1
substitution reaction with the formation
of a more stable carbocation than
product B.
D) Product A will be formed by an SN2
substitution reaction occurring in two
stages, the first with slow kinetics and
the second with fast kinetics.
E) The two compounds were obtained
by addition reaction, with compound B
having the highest percentage of
formation.
57
--
☑
14:30 A
Candidate Identification
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10. Amoxicillin (figure X) is one of the
most widely used antibiotics in the
penicillin family. The discovery and
synthesis of these antibiotics in the 20th
century made the treatment of infections
that were previously fatal routine.
About amoxicillin, mark the correct one:
HO
NH2 H
S
-N.
HO
Figura X. Amoxicilina
A) It has the organic functions amide,
ester, phenol and amine.
B) It has four chiral carbons and 8
stereoisomers.
C) The substitution of the aromatic ring
is of the ortho-meta type.
D) If amoxicillin reacts with an alcohol it
can form an ester.
E) The structure has two tertiary
amides.
62
The environmental police of a Brazilian state received a report of contamination of a river by inorganic arsenic, due to the excessive use of pesticides on a plantation on the riverbanks. Arsenic (As) is extremely toxic in its many forms and oxidation states. In nature, especially in groundwater, it is found in the form of arsenate (AsO ₄ ³ ⁻ ), which can be electrochemically reduced to As ⁰ and collected at the cathode of a coulometric cell. In this case, Potentiostatic Coulometry (at 25°C) was performed in an alkaline medium (pH = 7.5 throughout the analysis) to quantify the species. What potential (E) should have been selected/applied to perform the analysis, considering that this is an exhaustive electrolysis technique (until 99.99% of all AsO ₄ ³ ⁻ has been reduced to As ⁰ at the electrode, or n( final) = 0.01% n( initial )) and that the concentration of AsO ₄ ³ ⁻ found in the initial sample was 0.15 mmol/L ?
Data:
AsO ₄ 3 ⁻ (aq) + 2 H ₂ O ( l ) + 2 e ⁻ → A s O ₂ ⁻ ( a…
Genetic Analysis: An Integrated Approach (3rd Edition)
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