We can use Avogadro's number to convert the number of molecules to moles. Avogadro's number is 6.022 x 10^23 molecules per mole.
First, we need to determine how many moles of formic acid are represented by 4.01 x 10^25 molecules:
n = N / NA
where n is the number of moles, N is the number of molecules, and NA is Avogadro's number.
Substituting the given values, we get:
n = 4.01 x 10^25 / (6.022 x 10^23) = 66.6 moles
Therefore, the sample of formic acid contains 66.6 moles of formic acid.