[random87]

I'm trying to figure out how to compute the average molecular weight of a gas mixture (nitrogen dioxide and nitrogen tetroxide). I think I'm suppose to use this equation: M(mix)=X(NO2)M(NO2)+ X(N2O4)M(N2O4) , where I would just need to calculate the mole fractions and the molecular weight of the individual gases. Is this correct? If not assistance would be appreciated.

Also I need to determine the equilibrium constant, delta G standard and delta S standard. I think to find the equilibrium constant I need to use this equation: K= n(N2O4)/((2)n(NO2)) ? To find delta G I could then use this equation: detla G= -RTlnK ? and I have no idea how to find delta S standard.

Known: Pressure, Temp, Volume and three different weights of gas mixture.

[Borek]

I think I'm suppose to use this equation: M(mix)=X(NO2)M(NO2)+ X(N2O4)M(N2O4)

Looks OK to me.

K= n(N2O4)/((2)n(NO2))

Not 2 but ².

[random87]

Ok I'm trying to get the mole fraction and ran into a little bit of a problem:
 n_f= PV/RT= 0.95646 x10⁵cm³x267.403 x10^-6bar/ 8.31 x 303.15 K
                   = 0.010153 mol

n_i+x=119.283g/(92 g/mol)
                     = 1.29655 ?

n_i+x cannot equal n_f when n_i alone is larger. What am I doing wrong?

Also once this problem is fixed what equation would I use to determine delta S standard?