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.
..........NH4HS ==> NH3 + H2S
I..................0.......0
Equil...............p.......p
Kp = 0.075 = pNH3*pH2S
0.075 = p^2
p = sqrt(0.075) = ?
0.27
To calculate the equilibrium partial pressure of ammonia (NH3), we need to use the equation for the equilibrium constant (Kp) and the given value of Kp.
The equation for the equilibrium constant (Kp) is given by:
Kp = (P(NH3) * P(H2S)) / P(NH4HS)
We are given that Kp = 0.075.
To find the equilibrium partial pressure of ammonia (P(NH3)), we need to rearrange the equation:
P(NH3) = (Kp * P(NH4HS)) / P(H2S)
Given that the solid NH4HS remains, the partial pressure of NH4HS (P(NH4HS)) is not known. However, we can assume that its partial pressure is equal to its vapor pressure at that temperature, which we can find from a vapor pressure table.
Let's assume the vapor pressure of NH4HS (P(NH4HS)) at 23°C is 0.05 atm (just an example).
Similarly, we will also need the partial pressure of H2S (P(H2S)), which we do not have.
Therefore, without knowing the partial pressure of H2S, we cannot calculate the equilibrium partial pressure of ammonia (P(NH3)) accurately.
To calculate the equilibrium partial pressure of ammonia (NH3), we need to use the equilibrium constant (Kp) and the given conditions.
First, write the balanced equation for the reaction:
NH4HS (s) ↔ NH3 (g) + H2S (g)
The equilibrium constant expression (Kp) for this reaction is:
Kp = [NH3] * [H2S]
Since the equation states that "some solid NH4HS remains," we can assume that the concentration of NH4HS remains relatively constant and does not affect the equilibrium expression. Thus, we can ignore it in our calculations.
To calculate the equilibrium partial pressure of NH3, we need to remember that Kp is a ratio of partial pressures. Since the partial pressure of NH4HS is not included in the equilibrium constant expression, it becomes irrelevant. Therefore, we only need to find the partial pressure of nitrogen gas (NH3).
Given that Kp = 0.075 and the equation does not mention any values or concentrations, we need additional information to solve this problem. Specifically, we need to know the initial pressure or the concentration of NH3 or H2S.
Once you have the initial partial pressure of NH3 or H2S, you can use the equation Kp = [NH3] * [H2S] to solve for the equilibrium partial pressure of NH3.