At 23°C, Kp = 0.075 for the equilibrium: NH4HS (s) ↔ NH3 (g) + H2S (g) A sample of solid NH4HS is placed in a closed vessel and allowed to equilibrate. Calculate the equilibrium partial pressure (atm) of ammonia, assuming that some solid NH4HS remains. At 23°C, Kp = 0.075 for the equilibrium: NH4HS (s) NH3 (g) + H2S (g) A sample of solid NH4HS is placed in a closed vessel and allowed to equilibrate. Calculate the equilibrium partial pressure (atm) of ammonia, assuming that some solid NH4HS remains. 0.052 0.27 3.8 0.0049 0.075

To solve this equilibrium problem we will use an ICE table. This table represents 3 stages: I (Initial), C(Change) and E(Equilibrium). We will complete each row with the partial pressure in that stage. We do not include NH₄HS because solids and pure liquids do not participate in the equilibrium (and do not contribute to pressure). In this case,

NH₄HS(s) ↔ NH₃(g) + H₂S(g)

I 0 0

C +x +x

E x x

x represents the unknown pressure of ammonia at equilibrium. We can replace this in the equilibrium constant Kp,

[tex]Kp=pNH_{3}.pH_{2}S=x.x=x^{2} \\0.075=x^{2}\\x=\sqrt{0.075} = 0.27[/tex]

Since x = 0.27, the partial pressure of ammonia is 0.27 atm.