‘At 600.0 K, the equilibrium constant based on pressure is Kp = 1.83 x 10^2. Gaseous C2H4 and H2O are placed in a 1.2 L closed flask at 600.0 K. At equilibrium, the flask contains 0.0062 mol of C2H4 and 0.041 mol of H2O. Determine the equilibrium constant Kc assuming the pressure of the gases is in atmospheres.’
I know the relationship between Kp and Kc, but how do I determine the value of delta n? Do I find the limiting reagent to calculate the moles of C2H5OH and then use that?
Thanks!
Also, how would I find the partial pressure of C2H5OH if I don't know the number of moles there are?
Thanks so much, I feel like I half-understand these and then I don't.
To determine the value of Δn, which represents the change in the number of moles of gaseous molecules in the balanced chemical equation, you do not need to find the limiting reagent. Instead, you can directly calculate Δn by considering the balanced chemical equation.
In this case, the balanced chemical equation for the reaction might be:
C2H4 (g) + H2O (g) ⇌ C2H5OH (g)
Here, the reactants are C2H4 and H2O, and the product is C2H5OH. From this equation, we can determine the change in the number of moles of gaseous molecules as:
Δn = (moles of gaseous product) - (moles of gaseous reactants)
In this case, the only gaseous species is C2H4. Therefore:
Δn = (moles of C2H5OH) - (moles of C2H4)
Now, we can calculate Δn using the given values:
Δn = (0.0062 mol of C2H4) - (0 mol of C2H5OH)
Since there are no moles of C2H5OH present initially and only 0.0062 mol of C2H4 present at equilibrium, we can conclude that Δn = 0.0062 mol.
Now, using the relationship between Kp and Kc, which is given by:
Kp = Kc * (RT)^Δn
where R is the ideal gas constant and T is the temperature in Kelvin, we can rearrange the equation to solve for Kc:
Kc = Kp / (RT)^Δn
Given that Kp = 1.83 x 10^2 and the temperature is 600.0 K, you can use the appropriate values for R (0.0821 L·atm/(mol·K)) and Δn (0.0062 mol) to calculate Kc.