Iron II sulfide is produced when iron is heated with sulfur what is the therotical yield of FeS if 25.0 g Fe is heated with 32.0 g S?

Answer 1

Fe + S = FeS

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1) The first thing you need to determine is whether Fe or S is the limiting reagent.

To do this you need the Atomic Mass of both Fe and S, which can be found on the Periodic Table.

a) Fe = 56 and S = 32

Next, divide the given mass of the substance by the atomic mass.

a) Fe = (25.0 / 56) = 0.4464 (moles of Fe)

S = (32.0 / 32) = 1.0 (moles of S)

Next, divide the number of moles of substance by the coefficient in front of the element (see the above chemical equation)

a) Fe = (0.4464/1) = 0.4464

S = (1/1) = 1

Now you can see that the final number for Fe is smaller than the final number for S. This means that Fe is the limiting reagent and S is in excess.

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2) Now you can do a simple stoichiometry problem using Fe and converting to FeS. Always use the limiting reagent in the stoichiometry problem.

Note: FeS = 88

(25) (1) (88) = 2200 = 25

(56) (1) 88

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The theoretical yield of FeS is 25g.