Question
In: Chemistry
Lactic acid is very good at penetrating the skin. Because of this, it is used in...
Lactic acid is very good at penetrating the skin. Because of this, it is used in a number of products for skin care, such as exfoliating creams and chemical peels, and in formulations for transdermal delivery of medications, such as topical ointments and extended release patches for delivery through the skin. Lactic acid has a pKa of 3.86 in water at 25o C.
After graduation, you land your dream job at a small biotech firm specializing in novel antimicrobial agents. They have just developed a new drug, Poly-XSeption-L®, to help prevent antibiotic-resistant infections during local surgeries. Poly-XSeption-L® is to be applied to the skin at the site of the surgery in a liquid formulation containing lactic acid.
(a) The initial formulation being tested is a 1.0 wt% solution of Poly-XSeption-L® in a 0.015 M solution of aqueous lactic acid. Neglecting the effect of the antibiotic on the solution, what would you estimate the pH of this solution to be? State any assumptions you make.
(b) In clinical studies, it was found that the acidity of the initial formulation caused some problems with local irritation, and that Poly-XSeption-L® was not as effective below a pH of 4.2. It is proposed that sodium lactate be added to create a buffered solution with pH = 4.2. What concentration of sodium lactate should be used to achieve this pH?
Solutions
queen_honey_blossom answered 2 years agoRelated Solutions
What is the origin of the lactate or lactic acid?
What is the origin of the lactate or lactic acid?
The bacterium Micrococcus luteus lives on mammalian skin where it feeds on amino acids and lactic...
The bacterium Micrococcus luteus lives on mammalian
skin where it feeds on amino acids and lactic acid found in sweat.
Answer the following questions about carbohydrate metabolism[1] in
M. luteus.
M. luteus lacks any hexokinase orthologs (e.g. any
enzyme catalyzing the reaction glucose + ATP ⇌ glucose-6-phosphate
+ ADP) as well as any phosphohexose isomerase homologs (e.g. any
enzyme catalyzing the reaction glucose-6-phosphate ⇌
fructose-6-phosphate), but they express all other enzymes involved
in glycolysis. Are M. luteus bacteria capable of...
A solution containing a mixture of lactic acid and lactate was found to have a pH of 3.56. Calculate the ratio of the lactate concentration to the lactic acid concentration in this solution.
During exercise when the body lacks an adequate supply of oxygen to support energy production, the pyruvate that is produced from the breakdown of glucose is converted into lactate. High lactate levels can lead to acidity in the muscle cells as some of the lactate hydrolyzes to lactic acid. The dissociation of lactic acid to lactate is shown in the reaction below. Lactic acid has a pKa of 3.86. A solution containing a mixture of lactic acid and lactate was found to...
1) a) Calculate the pH of a buffer that is 0.12 M in lactic acid and...
1) a) Calculate the pH of a buffer that is 0.12 M in lactic acid
and 0.11 M in sodium lactate. (b) Calculate the pH of a buffer
formed by mixing 85 mL of 0.13 M lactic acid with 95 mL of 0.15M
sodium lactate.
2) You are asked to prepare a pH=3.00 buffer solution starting
from 1.25 L of a 1.00 M solution of hydroflouric acid (HF) and any
amount you need of sodium flouride (NaF). (a) What is...
Because it fumes at room temperatures, hydrochloric acid creates a very corrosive work environment. A machine...
Because it fumes at room temperatures, hydrochloric acid creates
a very corrosive work environment. A machine working in that
environment is deteriorating quickly and can be used for only one
more year, at which time it will be scrapped with no salvage value.
It was purchased 3 years ago for $88,000, and its operating cost
for the next year is expected to be $54,000. A more
corrosion-resistant challenger will cost $208,000 with an operating
cost of $54,000 per year. It...
Because it fumes at room temperatures, hydrochloric acid creates a very corrosive work environment. A machine...
Because it fumes at room temperatures, hydrochloric acid creates
a very corrosive work environment. A machine working in that
environment is deteriorating quickly and can be used for only one
more year, at which time it will be scrapped with no salvage value.
It was purchased 3 years ago for $88,000, and its operating cost
for the next year is expected to be $56,000. A more
corrosion-resistant challenger will cost $210,000 with an operating
cost of $54,000 per year. It...
Lactic acid (HC3H5O3), a weak monoprotic acid with a Ka = 1.4 x 10-4, is titrated...
Lactic acid (HC3H5O3), a weak
monoprotic acid with a Ka = 1.4 x 10-4, is
titrated with KOH. If you have 50.0 mL of a 0.500 M
HC3H5O3solution,
calculate the pH after 150.0 mL of 0.250 M KOH have been added:
What determines the taste of cheddar cheese? Experimenters assessed the concentration of lactic acid, acetic acid,...
What determines the taste of cheddar cheese? Experimenters
assessed the concentration of lactic acid, acetic acid, and
hydrogen sulfide in randomly chosen pieces of cheddar cheese that
were also rated for taste by a panel of food tasters (the higher
the score, the tastier). Data from the study are shown in the
provided table, “Acetic” and are actually log‑transformed
concentrations.
Taste
Acetic
H2S
Lactic
Taste
Acetic
H2S
Lactic
12.3
4.543
3.135
0.86
40.9
6.365
9.558
1.74
20.9
5.159
5.043
1.53...
Compare ethanol and lactic acid fermentation with regard to their products and the types of cells...
Compare ethanol and lactic acid fermentation with regard to
their products and the types of cells in which they occur.
Lactic acid is a common by-product of cellular respiration and is often said to cause the...
Lactic acid is a common by-product of cellular respiration and
is often said to cause the "burn" associated with strenuous
activity. A 25.0 mL sample of 0.109 M lactic acid (HC3H5O3, pKa =
3.86) is titrated with 0.109 M NaOH solution. (Assume that all
solutions are at 25°C.) (a) Calculate the pH after the addition of
the following amounts of NaOH. Vol. NaOH added pH 0 mL 4.0 mL 8.0
mL 12.5 mL 20.0 mL 24.0 mL 24.5 mL 24.9...
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