Question

When heated, hydrogen sulfide gas decomposes according to 2H2S(g) = 2H2(g) + S2(g).A 3.40g sample of H2S(g) is introduced into an evacuated rigid 1.25L container. The sealed container is heated to 483 K, and 3.72 x 10^-2 mol of S2(g) is present at equilibrium.
b) calculate the number of initial moles of hydrogen sulfide