How to calculate the equilibrium number of moles of gas in a vessel? Help!?

Question

I'm having a really hard time with this question!:

Dinitrogen tetroxide and nitrogen dioxide exist in the following equilibrium:

N2O4(g) <===> 2NO2(g)

When 11.04g of dinitrogen tetroxide were placed in a vessel of volume 4.80dm3 at fixed temperature, 5.52g of nitrogen dioxide were produced at equilibrium under a pressure of 100kPa. Use the data, where relevant,to answer the question that follows.

Calculate the equilibrium number of moles of NO2 in the vessel.

I'd really appreciate any help that I can get on this....alot!

Answer 1

Moles NO2 = mass / molar mass = 5.52 g /46.0 g/mol =0.120

Other data are not relevant