AS Chemistry moles help?

When aqueous aluminium sulphate reacts with aqueous barium chloride, a white precipitate of barium sulphate is formed. An equation for this reaction is shown below.
Al2(SO4)3(aq) + 3BaCl2(aq) → 3BaSO4(s) + 2AlCl3(aq)
Hydrated aluminium sulphate has the formula Al2(SO4)3.xH2O, where xH2O represents the water of crystallisation.
A sample of hydrated aluminium sulphate of mass 20.0 g was dissolved in water and the solution made up to 250 cm3.
An excess of aqueous barium chloride was added to a 25.0 cm3 portion of this aluminium sulphate solution.
All the sulphate ions reacted to form a precipitate of barium sulphate.
When filtered, washed and dried, the mass of the barium sulphate precipitate was 2.10 g.


3 (a) (i) Calculate the number of moles of barium sulphate (Mr = 233.4) in the precipitate - I got 0.009 moles

3 (a) (ii) Calculate the number of moles of aluminium sulphate in the 25.0 cm3 portion of
the solution and in the original 20.0 g sample.
Moles in 25.0 cm3 - I got 0.003 moles

Moles in original sample <- Don't know how to do this one? Any help would be appreciated