Acid Dissociation Constant

A 1.9 L vessel contains a gaseous mixture with 0.455 mol SO$_2$, 0.183 mol O$_2$, and 0.568 mol SO$_3$. Is the reaction at equilibrium? If not, what is the direction of the reaction?

2 SO$_2$ + O$_2$ $\leftrightharpoons$ 2 SO$_3$, K$_C$ = 280

A 1 L reaction vessel contains 2.5 mol A, 3 mol B, and initially 0 C. Find the concentrations of all species at equilibrium.

A + 2B $\leftrightharpoons$ 3 C , K$_C$ = 0.25

Find the equilibirium concentrations when starting with 0.50 M H$_2$ and 0.50 M Br$_2$

H$_2$ + Br$_2$ $\leftrightharpoons$ 2 HBr , K$_C$ = 143

0.20 M I$_2$ is placed in a reaction vessel. Find the concentrations of I$_2$ and I at equilibrium.

I$_2$ (g) $\leftrightharpoons$ 2 I (g) , K$_C$ = 3.8 x 10$^{-5}$