At a certain temperature , 0.960 mol of SO3 is placed in a 3.50 L container.

2SO3 ----> 2SO2 + O2

At equilibrium , 0.190 mol of O2 is present. Calculate kc.

i know that it starts off by
2SO3 -----> 2SO2 + O2
I 0.960 0 0
C -2x +2x x
_____________________
E 0.58 3.8 0.190

but then it says be sure to convert from moles to molar mass so i divided each equilibrium by 3.50 l . I did all of this but i still do not get the right answer !!! Someone help me please thank you

0.960/3.5L = 0.274M

0.190/3.5L = 0.0543M

............2SO3 ==> 2SO2 + O2
initial....0.274......0.....0
change.....-2x........2x.....x
equil.....0.274-2x....2x....0.0543
So you know x must be 0.0543 which will allow you to calculate 2x and from there SO3 and SO2 at equilibrium. Then substitute into Kc expression and solv for Kc.

I did what you said but I keep getting the wrong answer no matter what I do.

To calculate the equilibrium constant (Kc), you need to use the concentrations of the reactants and products at equilibrium. Here's a step-by-step solution to help you calculate Kc:

1. Start with the balanced chemical equation:
2SO3 ⇌ 2SO2 + O2

2. Write down the initial and equilibrium concentrations (in mol/L):

Initial:
[SO3] = 0.960 mol / 3.50 L = 0.274 mol/L

Equilibrium:
[SO3] = 0.960 mol - (2 * x) mol
[SO2] = 0 + (2 * x) mol
[O2] = 0 + x mol

Note: The stoichiometric coefficients in the balanced equation represent the change in moles, so we assume that the initial concentrations of SO2 and O2 are both 0.

3. Substitute the equilibrium concentrations into the equilibrium expression (Kc):

Kc = ([SO2]^2 * [O2]) / [SO3]^2

Kc = [(2 * x)^2 * x] / [(0.960 - 2x)^2]

4. Use the given equilibrium concentration of O2 to solve for x:

[O2] = 0.190 mol / 3.50 L = 0.0543 mol/L

0.0543 = x

5. Substitute the value of x back into the equilibrium expression:

Kc = [(2 * 0.0543)^2 * 0.0543] / [(0.960 - 2 * 0.0543)^2]

Simplify and calculate the value of Kc.

Make sure you also check your calculation for any rounding errors.

To calculate the value of Kc, you need to determine the equilibrium concentrations of each species. It seems like you've correctly set up the initial and change columns in the ICE table, but made a mistake when converting from moles to molar concentrations (mol/L).

Here's the corrected version of the table:

2SO3 -----> 2SO2 + O2
I: 0.960 0
C: -2x x
-------------------------------
E: 2x x

From the given information, at equilibrium, the concentration of O2 (x) is 0.190 mol in a 3.50 L container. Therefore, the molar concentration of O2 is:

[O2] = x / Volume = 0.190 mol / 3.50 L ≈ 0.0543 mol/L

Similarly, the molar concentration of SO3 reacting (2x) is:

[SO3] = (2x) / Volume ≈ (2 * 0.190 mol) / 3.50 L ≈ 0.1086 mol/L

And the molar concentration of SO2 produced (2x) is:

[SO2] = (2x) / Volume ≈ (2 * 0.190 mol) / 3.50 L ≈ 0.1086 mol/L

Now, you can plug the equilibrium concentrations into the equilibrium expression for Kc:

Kc = ([SO2]^2 * [O2]) / [SO3]^2

Kc = ((0.1086 mol/L)^2 * (0.0543 mol/L)) / (0.1086 mol/L)^2 = 0.0543

Therefore, the value of Kc is approximately 0.0543.