First, determine the amount of methanol in moles by dividing the given number of molecules by the Avogadro's number.
(9.66 x 10^24 molecules) / (6.022 x 10^23 molecules / mol) = 16.04 moles
Multiply this number of moles to the molar weight of methanol which is equal to 32 g/mol
(16.04 moles) x (32 g/mol) = 513.28 grams
Therefore, the mass of methanol is approximately equal to 513.28 grams.