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Submitted by kassi17 on Wed, 12/02/2009 - 14:57

If 104 g of solid Fe2S3 reacts stoichiometrically according to the balanced equation, how many milliliters of 2.11 M aqueous HCl are required?

Fe2S3(s) + 6HCl(aq) ? 3H2S(g) + 2FeCl3(aq) 

First find the molar mass of Fe2S3. Using simple atomic masses, it is (56x2)+(32x3) g/mol

Fe2S3(s) + 6HCl(aq) ? 3H2S(g) + 2FeCl3(aq) 
1 mole        6 mol

With the molar mass of Fe2S3 and you know that this will react with 6 moles HCl
Then find the number of moles of HCl that will react with 104g of Fe2S3

Once you have the number of moles HCl and you know the molarity, plug into
Volume in litres = no. of mole / molarity