How many moles of naoh are required to neutralize 300mg of aspirin?

No formula, just dimensional analysis and ratiOS. Aspirin is C9H8O6

300 mg C9H8O6 (1 gram/1000 milligrams)(1 mole C9H8O6/212.154 grams)

= 1.41 X 10^-3 moles aspirin

just get milligrams up to grams and divide that by the molar mass