Stoichiometry problem

Question

acetylsalicylic acid (C9H8O4) is a monoprotic acid commonly known as aspirin. A typical aspirin tablet, however, contains only a small amount of the acid. In an experiment to determine its composition, an aspirin table was crushed and dissolved in water. It took 12.25 mL of 0.1466 M NaOH to neutralize the solution. CALCULATE THE NUMBER OF GRAINS OF ASPIRIN IN THE TABLET. ( one grain = 0.0648g)

THANK YOU SO MUCH! WILL YOU PLEASE SHOW THE SOLUTION OR EVEN THE FORMULA? TNX

Answer 1

You don't need a special formula.  Just think about what's happening.

Moles NaOH = vol NaOH (L) x conc NaOH (M)

Moles aspirin = moles NaOH (why?)

Use the molar mass of aspirin to convert moles to g, and the fact he were given to convert g to grains (answer in g x [1 grain/0.0648g] = answer in grains).