Heating 1.0 mole of ammonia and 1.0 mole of molecular nitrogen at 723k in a 10L flask,the following equilibrium is observed:
N2(g)+3H2(g)=2NH3(g)
when the equilibrium is reached ,0.40 moles of molecular hydrogen are present in the flask,determine Kp and Kc and equilibrium composition of the mixture.
initial (N2) = 1/10 = 0.1
initial (H2) = 1/10 = 0.1
equilibrium (H2) = 0.4/10 = 0.04
.......N2 + 3H2 ==> 2NH3
I.....0.1..0.1......0
C.....-x....-3x.....+2x
E..0.1-x...0.1-3x...2x
The problem tells that 0.1-3x = 0.04 so x = 0.02. That allows you to calculate composition of each component. Plug values of each component into Kc expression and solve for Kc.
Plug Kc into Kp = Kc(RT)^delta n and solve for Kp.
To determine Kp and Kc and the equilibrium composition of the mixture, we need to go through several steps:
Step 1: Write the balanced equation:
N2(g) + 3H2(g) ⇌ 2NH3(g)
Step 2: Write the expression for Kp:
Kp = (PNH3)^2 / (PN2 * PH2^3)
where PNH3, PN2, and PH2 are the partial pressures of NH3, N2, and H2, respectively, at equilibrium.
Step 3: Write the expression for Kc:
Kc = ([NH3]^2) / ([N2] * [H2]^3)
where [NH3], [N2], and [H2] are the molar concentrations of NH3, N2, and H2, respectively, at equilibrium.
Step 4: Calculate the given equilibrium concentrations:
Given:
Initial moles of NH3 = 1.0 mol
Initial moles of N2 = 1.0 mol
Initial moles of H2 = 0.40 mol
Total initial moles = 1.0 + 1.0 + 0.40 = 2.40 mol
Now, the moles of NH3 at equilibrium can be determined from the balanced equation:
Starting with 1.0 mole of NH3 and 2.40 moles of total reactants,
1.0 mole of NH3 and 1.0 mole of N2 react to form 2.0 moles of NH3.
Therefore, at equilibrium, the concentration of NH3 is 2.0 mol / 10 L = 0.20 mol/L.
The moles of N2 and H2 can be calculated by subtracting the moles of NH3 from the total initial moles:
Moles of N2 = 1.0 - 1.0 = 0.0 mol
Moles of H2 = 0.40 - 3.0 * 1.0 = -2.60 mol (Note that the negative sign indicates that H2 is in excess).
Step 5: Calculate Kp and Kc using the equilibrium concentrations:
Kp = (0.20^2) / (0.0 * (-2.60)^3)
(Note: The value for PN2 is zero since there are no moles of N2 left at equilibrium.)
Similarly, Kc = ((0.20)^2) / ((0.0) * (-2.60)^3)
As dividing by zero is undefined, Kp and Kc cannot be calculated as the denominator becomes zero.
Furthermore, the negative value for the moles of H2 indicates that the reaction did not proceed in the forward direction. It suggests that there might be an error or inconsistency in the given information or calculations.
In conclusion, Kp and Kc cannot be calculated, and the equilibrium composition of the mixture is not available due to the inconsistent data provided.