A researcher put 10.0 moles of N2O into a 2-L container at some temperature where it decomposes according to the following: N2O = 2N2+ O2. At equilibrium 2.20 moles of N2O remain. Calculate the Kc for the reaction.
How am I supposed to fill in the ICE chart if Kc isn't given for me to plug into the constant equation? Please help, I can't find the the equilibrium for 2N2 + O2.
To calculate the equilibrium constant (Kc) for the given reaction, you need to know the concentrations of all the species involved at equilibrium. In this case, the problem provides the information that at equilibrium, 2.20 moles of N2O remain.
To fill in the ICE (Initial, Change, Equilibrium) chart, you'll need to make some assumptions. First, assume that x moles of N2O decompose to form 2x moles of N2 and x moles of O2 at equilibrium.
Using this assumption, you can now fill in the ICE chart as follows:
N2O: 10.0 moles -> -x -> 10.0 - x moles
N2: 0 moles -> +2x -> 2x moles
O2: 0 moles -> +x -> x moles
Notice that the initial moles for N2 and O2 are both zero since they are not present initially but are formed during the reaction.
At equilibrium, the moles of N2O remaining is given as 2.20 moles. Therefore, you can set up the equation:
10.0 - x = 2.20
Solving for x, you get x = 7.80 moles.
Now you have the concentration of N2O at equilibrium, which is 2.20 moles / 2 L = 1.10 M.
Since the equilibrium concentration for N2 and O2 is given by 2x and x respectively, the concentrations for N2 and O2 are:
[N2] = 2(7.80) / 2 L = 7.80 M
[O2] = 7.80 / 2 L = 3.90 M
You now have all the equilibrium concentrations required to calculate Kc. The equilibrium constant (Kc) expression for the given reaction is:
Kc = ([N2]^2 * [O2]) / [N2O]^2
Plugging in the values:
Kc = (7.80^2 * 3.90) / (1.10^2)
= 271.17
Therefore, the Kc for the reaction N2O = 2N2 + O2 is 271.17.
Kc is what they want you to calculate.
Initial (N2O) = 10 mols/2L = 5.0 M
Eq (NO2) = 2.1/2 = 1.1 M.
Your equation isn't balanced.
.......2N2O ==> 2N2 + O2
I......5.0M......0.....0
C......-2x......+2x....x
E......1.10M.....2x....x
So 2x = 5.0-1.1 = 3.9
Solve for x, fill in the ICE chart, substitute into the Kc expression and solve for Kc. Just some reasoning to get the ICE chart filled in. Post your work if you have more trouble.