A mixture of h2 s and h2s is held in a 10-l vessel at 90

Question

A mixture of H2, S, and H2S is held in a 1.0-L vessel at 90 °C and reacts according to the equation:

H₂(g) + S(s) ↔ H₂S(g)

At equilibrium the mixture contains 0.46 g of H2S and 0.40 g H2.

a) Write the equilibrium-constant expression for this reaction.

(b) What is the value of Kc for the reaction at this temperature?

(c) Why can we ignore the amount of S when doing the calculation in part (b)?