What is the least amount of 20 percent H2SO4 solution in grams to dissolve 11 grams of FeS?

Question

Please add some details as I'm still learning.

Answer 1

First, write a correctly balanced equation for the "reaction" of H₂SO₄ with FeS.

H₂SO₄ + FeS ==> FeSO₄ + H₂S

Next, we want to convert all reactants to moles.

11 g FeS x 1 mole FeS/87.91 g = 0.125 moles FeS

moles H₂SO₄ needed to react with 0.125 moles FeS = 0.125 mol FeS x 1 mol H2SO4/mol FeS = 0.125 mol H₂SO₄ required

To find grams of H2SO4 solution needed we first convert 0.125 moles to grams and then account for the fact that the solution is only 20% H₂SO₄:

0.125 moles H2SO4 x 98.08 g/mol = 12.26 g

20% H2SO4 (w/w) = 20 g H2SO4/100 g solution. Therefore 12.26 g/20 (x100) = 61.3 g solution = 61 g (2 sig figs)

(NOTE: this assumes that the 20% H₂SO₄ is given as a mass/mass % and not a mass/volume %)

Answer 2

Maybe the question should be "to react" instead of "to dissolve".

You need a balanced equation.

H2SO4 + FeS ----> FeSO4 + H2S.

Convert 11 g FeS to moles FeS using the molar mass of FeS, and that will = moles H2SO4. Convert to g H2SO4 using molar mass. Then, since the solution of H2SO4 is 20% H2SO4, multiply by 100/20 to get the g of solution.

"Some details", not all.