Calculate the mass of iron sulfide, which can be obtained by the interaction of 7 g of iron with sulfur.

Let’s write the reaction equation:

Fe + S = FeS;

Now let’s calculate the amount of moles (n) of iron, since we are given its mass:

n (Fe) = m (Fe): M (Fe) = 7 g: 56 g / mol = 0.125 mol;

Since all substances in the equation have a coefficient of 1 (conditionally), this means that the number of moles of FeS = the number of moles of Fe:

n (FeS) = 0.125 mol.

Now we just have to find the FeS mass:

m (FeS) = n (FeS) * M (FeS) = 0.125 mol * 88 g / mol = 11 g (iron sulfide is formed during the reaction). M (FeS) = Ar (Fe) + Ar (S) = 56 + 32 = 88 g / mol (according to the periodic table, we find the values of Ar).