You have a $18mL$ sample of acetylcholine $($a neurotransmitter$)$ with an unknown concentration and a pH of $7\mathrm{.}82.$ 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 $5\mathrm{.}66.$ Assuming there was no buffer in the assay mixture, determine the number of nanomoles of acetylcholine in

the original $18mL$ 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.

Acetylcholine

Choline

Acetate

acetycholine in original sample:

nmol