When solid NH4HS is placed in a closed flask at 28 C, the solid dissociates according to the equation:

Question

NH4HS(s) <=> NH3(g) + H2S(g)

The total pressure of the equilibrium mixture is 0.766 atm. Determine Kp at this temperature.
Choose one answer.

a. 0.147

b. 0.766

c. 0.587

d. 0.383

e. 1.53

Answer 1

NH4HS(s) <=> NH3(g) + H2S(g)

p = partial pressure.
Kp = pNH3 x pH2S

Since the total pressure is 0.766 atm, and the number of moles NH3 = number of moles H2S, won't the partial pressure of each gas be just 1/2 of the total pressure? Substitute into Kp and solve. Check my thinking.