Ammonium bisulfide, NH4HS, forms ammonia, NH3, and hydrogen sulfide, H2S, through the reaction NH4HS(s)⇌NH3(g)+H2S(g) This reaction has a Kp value of 0.120 at 25 ∘C.

Question

An empty 5.00-L flask is charged with 0.350 g of pure H2S(g), at 25 ∘C.

What is the initial pressure of H2S(g) in the flask?

Answer 1

moles H₂S(g) = 0.350 g x 1 mol/34 g = 0.0103 moles

PV = nRT

P = nRT/V = (0.0103 mol)(0.0821 Latm/Kmol)(298K) / 5.00 L

P = 0.0504 atm