2 Calculate the equilibrium concentrations of N204 and NO2 a

2. Calculate the equilibrium concentrations of N204 and NO2 at 25°C in a vessel that contains initial concentration of 0.0500M of N204. Kc = 4.64 x 10-3 at 25°C. N204 (g) 2NO2 (g)

Solution

the reaction is N2O4<--------->2NO2(g)

Kc= [NO2]²/ [N2O4]= equilibrium constant

preparing the ICE Table

                                        [N2O4]                             [NO2]

initial                                      0.05M                             0

change                                   -x                                    2x

Equilibrium                      0.05-x                                 2x

KC= (2x)²/ (0.05-x)= 4.64*10^-3, x²/(0.05-x)= 4.64*10^-3/4= 1.16*10^-3

when solved using excel , x=0.00694, hence at equilibirum [N2O4]= 0.05-0.00694= 0.04306 and [NO2] =2*0.00694=0.01388 M