At 25°C, Kp = 2.910−3 for the following reaction.
NH4OCONH2(s) 2 NH3(g) + CO2(g)
In an experiment carried out at 25°C, a certain amount of NH4OCONH2 is placed in an evacuated rigid container and allowed to come to equilibrium. Calculate the total pressure in the container at equilibrium.
To calculate the total pressure in the container at equilibrium, we need to use the equilibrium constant (Kp) and the relationship between partial pressures of the gases involved in the reaction.
According to the equation given, the reaction is:
NH4OCONH2(s) -> 2 NH3(g) + CO2(g)
The equilibrium constant expression for this reaction is:
Kp = (P(NH3)^2 * P(CO2)) / P(NH4OCONH2)
In this equation:
- P(NH3) represents the partial pressure of NH3(g) at equilibrium.
- P(CO2) represents the partial pressure of CO2(g) at equilibrium.
- P(NH4OCONH2) represents the partial pressure of NH4OCONH2(s) at equilibrium.
Given that Kp = 2.910−3 and the reaction is carried out at 25°C, we need to find the partial pressures of NH3 and CO2 in terms of P(NH4OCONH2).
Assuming the initial pressure of NH4OCONH2(s) is negligible, we can consider its partial pressure at equilibrium to be zero.
Let's represent the equilibrium partial pressures of NH3 and CO2 as P(NH3) and P(CO2), respectively. Since we know that 2 moles of NH3 are formed for every mole of NH4OCONH2, we can express P(NH3) in terms of P(NH4OCONH2):
P(NH3) = 2 * P(NH4OCONH2)
Similarly, since 1 mole of CO2 is formed for every mole of NH4OCONH2, we can express P(CO2) in terms of P(NH4OCONH2):
P(CO2) = P(NH4OCONH2)
Now, substituting these expressions into the equilibrium constant expression, we get:
Kp = (P(NH3)^2 * P(CO2)) / P(NH4OCONH2)
Kp = (4 * P(NH4OCONH2)^2 * P(NH4OCONH2)) / P(NH4OCONH2)
Kp = 4 * P(NH4OCONH2)^2
Since the equilibrium constant (Kp) is given as 2.910−3, we can set up the equation:
2.910−3 = 4 * P(NH4OCONH2)^2
Now, solve for P(NH4OCONH2):
P(NH4OCONH2)^2 = (2.910−3) / 4
P(NH4OCONH2) = √((2.910−3) / 4)
Once you calculate P(NH4OCONH2), you can determine the total pressure in the container at equilibrium by adding the partial pressures of NH3, CO2, and NH4OCONH2.
Total pressure at equilibrium = P(NH3) + P(CO2) + P(NH4OCONH2)