decide comparative magnitude of kp and kc for NH3 synthesis?
Kp > Kc for NH3 synthesis.
To determine the comparative magnitudes of Kp and Kc for NH3 synthesis, we need to understand the relationship between the two equilibrium constants.
Kp and Kc are related through the ideal gas law, which states that the pressure of a gas is directly proportional to its concentration when the temperature and volume are constant.
For the reaction N2(g) + 3H2(g) ⇌ 2NH3(g), we can write the equilibrium expression in terms of pressure (Kp) and molar concentration (Kc):
Kp = (P(NH3))^2 / (P(N2) * (P(H2))^3)
Kc = ([NH3]^2) / ([N2] * ([H2])^3)
Now, let's analyze the effect of pressure and concentration on the comparative magnitude of Kp and Kc for NH3 synthesis:
1. Pressure:
Since Kp is based on partial pressures, changes in pressure have a direct impact on Kp. Increasing the total pressure by increasing the pressure of any reactant or product will increase Kp and vice versa. On the other hand, Kc is based on molar concentrations and is independent of pressure changes.
2. Concentration:
Kc is based on molar concentrations, so it is directly affected by changes in concentration. Increasing the concentration of any reactant or product will increase Kc and vice versa. Kp, however, is based on partial pressures and is independent of changes in concentration.
Based on these considerations, we can conclude that the comparative magnitude of Kp and Kc for NH3 synthesis will depend on the reaction conditions. If the pressure remains constant, Kp and Kc will have similar magnitudes since changes in concentration will not significantly affect Kp. However, if the pressure varies, Kp will be affected, and its magnitude may deviate from that of Kc.
To compare the magnitudes of Kp (the equilibrium constant in terms of partial pressures) and Kc (the equilibrium constant in terms of concentrations) for the synthesis of NH3, we need the balanced chemical equation for the reaction:
N2(g) + 3H2(g) ⇌ 2NH3(g)
Now, the equilibrium constant expression Kp is given by:
Kp = (P(NH3))^2 / (P(N2) * P(H2)^3)
Where P(NH3) represents the partial pressure of NH3, P(N2) represents the partial pressure of N2, and P(H2) represents the partial pressure of H2.
On the other hand, the equilibrium constant expression Kc is given by:
Kc = ( [NH3]^2 ) / ( [N2] * [H2]^3 )
Where [NH3] represents the concentration of NH3, [N2] represents the concentration of N2, and [H2] represents the concentration of H2.
To compare the magnitudes of Kp and Kc for NH3 synthesis, we need to consider the stoichiometric coefficients of the balanced equation.
Since the stoichiometric coefficient for NH3 is 2, when we compare the expressions for Kp and Kc, we can see that the concentration of NH3 ([NH3]) raised to the power of 2 is equivalent to the partial pressure of NH3 (P(NH3)) squared.
Similarly, since the stoichiometric coefficient for N2 is 1 and for H2 is 3, the concentration of N2 ([N2]) is equivalent to the partial pressure of N2 (P(N2)) and the concentration of H2 ([H2]) raised to the power of 3 is equivalent to the partial pressure of H2 (P(H2)) cubed.
Therefore, the magnitude of Kp is equal to the magnitude of Kc, as they have the same mathematical expression.