Do you know how to set up the ICE? That's what you need to do. If you know but are confused, tell us what you don't understand about it.
At 55 degrees celcius, the K for the reaction: 2NO2 (g) <=> N2O4(g) is 1.15
Calculate the concentration of N2)4(g) present in equilibrium with 0.50 mole of NO2.
Please help. Thanks!