Question

A sample of gas in which [h2s] = 5.25 m is heated to 1400 k in a sealed vessel. after chemical equilibrium has been achieved, what is the value of [h2s]? assume no h2 or s2 was present in the original sample.

Answer 1

when the reaction equation is:

by using the ICE equation:

2H2S(g) ↔ 2 H2(g) + S2(s)

initial 5.25 0 0

change -2X +2X +X

Equ (5.25-2X) 2X X

and when Kc = 2.2 x 10^-4

Kc = [H2]^2/ [H2S]^2

= (2x)^2 / (5.25-2X)^2 by solving for X

∴X = 0.038 M

∴[H2S] = 5.25 - 2X

= 5.25 - (2*0.038)

= 5.174 M