At 25 deg C, Kc is 5.84x10-3 for the dissociation of dinitrogen tetraoxide to nitrogen dioxide.

Question

N2O4(g) ==== 2NO2(g)
a) Calculate the equilibrium concentration of both gases when 4.00 grams of N2O4 is placed at 2.00-liter flask at 25 deg C.

b) What will be the new equilibrium concentrations if the volume of the system is suddenly increased to 3.00-liters at 25 deg C?
c) What will be the new equilibrium concentrations if the volume is decreased to 1.00-liter at 25 deg C?

Answer 1

mols N2O4 = 4/molar mass = 4/92 = about 0.0435M
M N2O4 = 0.0435/2 = about 0.0217M

..........N2O4 ==> 2NO2
I.........0.0217.....0
C.........-x........2x
E.......0.0217-x....2x

Substitute the E line into Kc expression and solve for x and 0.0217-x

b and c are done the same way.
Post your work if you get stuck.