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: CH₂ H₂O CH3 HO–CH,—CH,—*N–CH, + CH, Choline CH3 CH, T Acetate O + H+ nmol

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: CH₂ H₂O CH3 HO–CH,—CH,—N–CH, + CH, Choline CH3 CH, T Acetate O + H+ nmol

Principles of Modern Chemistry

8th Edition

ISBN:9781305079113

Author:David W. Oxtoby, H. Pat Gillis, Laurie J. Butler

Publisher:David W. Oxtoby, H. Pat Gillis, Laurie J. Butler

Chapter16: Solubility And Precipitation Equilibria

Section: Chapter Questions

Problem 70AP

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