Acertain amount of h2s was added to a 2.0 l flask and allowed to come to equilibrium. at equilibrium, 0.072 mol of h2 was found. how many moles of h2s were originally added to the flask?

0.098 moles H₂S

Explanation:

The reaction that takes place is

We can express the equilibrium constant as:

With the volume we can calculate the equilibrium concentration of H₂:

The stoichiometric ratio tells us that the concentration of S₂ is half of the concentration of H₂:

Now we can calculate [H₂S]:

So 0.013 M is the concentration of H₂S at equilibrium.

Initial moles of H₂S - Moles of H₂S that reacted into H₂ = Moles of H₂S at equilibrium

Initial moles of H₂S - 0.072 mol = 0.026 mol

Initial moles of H₂S = 0.098 moles H₂S

0.88m hope i am correct : )