At a certain temperature, 0.780 mol SO 3 0.780 mol SO3 is placed in a 4.00 L 4.00 L container. 2 SO 3 ( g ) − ⇀ ↽ − 2 SO 2 ( g ) + O 2 ( g ) 2SO3(g)↽−−⇀2SO2(g)+O2(g) At equilibrium, 0.100 mol O 2 0.100 mol O2 is present. Calculate K c .

0.00297

Explanation:

Moles of   = 0.780 mole

Volume of solution = 4.00 L

Initial concentration of =

Equilibrium concentration of =

The given balanced equilibrium reaction is,

Initial conc.         0.195 M            0 M       0 M

At eqm. conc.     (0.195-2x) M   (2x) M   (x) M

The expression for equilibrium constant for this reaction will be,

Now put all the given values in this expression, we get :

Given = x = 0.025 M

Thus is 0.00297