To find the molar mass of Fe2O3, we need to add the atomic masses of the elements present.

Fe = 55.84 g/mol
O = 16.00 g/mol

Fe2O3 = 2(Fe) + 3(O) = 2(55.84) + 3(16.00) = 111.68 + 48.00 = 159.68 g/mol

Now, we can use the molar mass of Fe2O3 to find the mass of Fe2O3 in the sample.

Given:
m(Fe(OH)3)2 = 30.9 g

Now, we need to find the molar mass of Fe(OH)3:
Fe(OH)3 = Fe + 3(O) + 3(H) = 55.84 + 3(16.00) + 3(1.01) = 55.84 + 48.00 + 3.03 = 106.87 g/mol

Now, we can calculate the mass of Fe2O3 in the sample using the ratio of molar masses:

m(Fe2O3) = (m(Fe(OH)3)2 molar mass of Fe2O3) / molar mass of Fe(OH)3
m(Fe2O3) = (30.9 159.68) / 106.87
m(Fe2O3) = 4743.432 / 106.87
m(Fe2O3) ≈ 44.38 g

Therefore, the mass of Fe2O3 in the sample is approximately 44.38 grams.