A 12-oz (355-mL) Pepsi contains 38.9 mg caffeine (molar mass ?? 194.2 g/mol). Assume that the Pepsi, mainly water, has a density of 1.01 g/mL.
For such a Pepsi, calculate:
(a) its caffeine concentration in ppm
(b) its molarity of caffeine
(c) the molality of caffeine.