You decide to put your growing knowledge of chemistry to profit by making and selling boutique soaps that are ultra mild and have an almost neutral pH. What is the pH of your best liquid soap made from a fatty acid (HA) that has a pKa value of 2.0? The concentration of the active ingredient, a fatty acid salt (NaA), is 1.0 M NaA.

You decide to put your growing knowledge of chemistry to profit by making and selling boutique soaps that are ultra mild and have an almost neutral pH. What is the pH of your best liquid soap made from a fatty acid (HA) that has a pKa value of 2.0? The concentration of the active ingredient, a fatty acid salt (NaA), is 1.0 M NaA.

Chemistry: The Molecular Science

5th Edition

ISBN:9781285199047

Author:John W. Moore, Conrad L. Stanitski

Publisher:John W. Moore, Conrad L. Stanitski

Chapter15: Additional Aqueous Equilibria

Section: Chapter Questions

Problem 105QRT: Apatite, Ca5(PO4)3OH, is the mineral in teeth. On a chemical basis explain why drinking milk...

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A pharmacist needs to prepare an oral solution for valproic acid at a dose of 144 mg. If you prepare a 10 mL valproic acid solution using a buffer solution at pH 3.8, what is the solution pH? Valproic acid has a pKa value of 4.8. MW = 144 What is the percentage of valproic acid that exists in the deprotonated (ionized) form?
You have a 18 mL sample of acetylcholine (a neurotransmitter) with an unknown concentration and a pH of 7.82. You incubate this sample with the enzyme acetylcholinesterase to convert all of the acetylcholine to choline and acetic acid. The acetic acid dissociates to yield acetate and hydrogen ions. At the end of the incubation period, you measure the pH again and find that it has decreased to 5.66. Assuming there was no buffer in the assay mixture, determine the number of nanomoles of acetylcholine in the original 18 mL sample. Tip: your answer should have two significant digits! Only the mantissa (the digits to the right of the decimal) are significant when you raise a decimal number to a power. CH,—C−O−CH,—CH,—*N—CH, Acetylcholine CH 3 acetycholine in original sample: CH3 H₂O CH3 HO–CH,—CH,—*N–CH, + CH, Choline CH3 CH, T Acetate O + H+ nmol
You have a 15 mL sample of acetylcholine (a neurotransmitter) with an unknown concentration and a pH of 8.06. You incubate this sample with the enzyme acetylcholinesterase to convert all of the acetylcholine to choline and acetic acid. The acetic acid dissociates to yield acetate and hydrogen ions. At the end of the incubation period, you measure the pH again and find that it has decreased to 5.91. Assuming there was no buffer in the assay mixture, determine the number of nanomoles of acetylcholine in the original 15 mL sample. O= CH3 Acetylcholine H₂O CH,—C−O−CH,—CH,—*N-CH, → HO−CH,—CH,—*N–CH, + CH,—C−O + H* CH3 CH 3 Choline CH3 Acetate
The pKa of a weak acid was determined by measuring the pH of a solution containing the weak acid at 0.30 M and its conjugate base at 0.30 M. The measured pH was 8.0. What is the pKa of the weak acid?
You have a 18 mL sample of acetylcholine (a neurotransmitter) with an unknown concentration and a pH of 8.35. You incubate this sample with the enzyme acetylcholinesterase to convert all of the acetylcholine to choline and acetic acid. The acetic acid dissociates to yield acetate and hydrogen ions. At the end of the incubation period, you measure the pH again and find that it has decreased to 6.03. Assuming there was no buffer in the assay mixture, determine the number of nanomoles of acetylcholine in the original 18 mL sample.
You have a 12 mL sample of acetylcholine (a neurotransmitter) with an unknown concentration and a pH of 8.14. You incubate this sample with the enzyme acetylcholinesterase to convert all of the acetylcholine to choline and acetic acid. The acetic acid dissociates to yield acetate and hydrogen ions. At the end of the incubation period, you measure the pH again and find that it has decreased to 6.55. Assuming there was no buffer in the assay mixture, determine the number of nanomoles of acetylcholine in the original 12 mL sample. Acetycholine in original sample:________ nmol
You have a 16 mL sample of acetylcholine (a neurotransmitter) with an unknown concentration and a pH of 7.66. You incubate this sample with the enzyme acetylcholinesterase to convert all of the acetylcholine to choline and acetic acid. The acetic acid dissociates to yield acetate and hydrogen ions. At the end of the incubation period, you measure the pH again and find that it has decreased to 5.52. Assuming there was no buffer in the assay mixture, determine the number of nanomoles of acetylcholine in the original 16 mL sample. Acetylcholine CH₂ acetycholine in original sample: CH,—C−O−CH,—CH,AN-CH, HO–CH,—CH,*N–CH, + CHy H₂O I CH3 CH3 Choline CH₂ CH,-GO + H Acetate nmol
During the fermentation of wine, a buffer system consisting of tartaric acid and potassium hydrogen tartrate is produced by a biochemical reaction. Assuming that at some time the concentration of potassium hydrogen tartrate is twice that of tartaric acid, calculate the pH of the wine. The pKa of tartaric acid is 2.96.
What is the pH of a solution containing 0.50 moles of benzoic acid and 0.75 moles of sodium benzoate if the pka is 4.19?
You have a 20 mL sample of acetylcholine (a neurotransmitter) with an unknown concentration and a pH of 8.17. You incubate this sample with the enzyme acetylcholinesterase to convert all of the acetylcholine to choline and acetic acid. The acetic acid dissociates to yield acetate and hydrogen ions. At the end of the incubation period, you measure the pH again and find that it has decreased to 6.70. Assuming there was no buffer in the assay mixture, determine the number of nanomoles of acetylcholine in the original 20 mL sample. -Å-—•- CH,—C−O−CH,—CH,—*N–CH, Acetylcholine CH₂ acetycholine in original sample: CH₂ H₂O CH₂ I HO–CH,—CH,—*N–CH, + CH Choline CH₂ CHO Acetate H* nmol
What will be the pH of a buffer solution containing an acid with a pKa of 5.4 with an acid concentration equivalent to that of its conjugate base?
You have a 11 mL sample of acetylcholine (a neurotransmitter) with an unknown concentration and a pH of 8.22. You incubate this sample with the enzyme acetylcholinesterase to convert all of the acetylcholine to choline and acetic acid. The acetic acid dissociates to yield acetate and hydrogen ions. At the end of the incubation period, you measure the pH again and find that it has decreased to 6.62. Assuming there was no buffer in the assay mixture, determine the number of nanomoles of acetylcholine in the original 11 mL sample. CH,—C−O−CH,—CH,—*N-CH, Acetylcholine CH3 acetycholine in original sample: I CH₂ H₂O CH₂ HO–CH,—CH,—*N–CH, + CH,-C−O + H* CH₂-8-0 Choline | CH3 Acetate nmol