For the reaction: A+B <-----> 2C (all gases)

2.0 mol A, 2.8 mol B and 1.0 mol C are placed in a 2.0 L container and allowed to reach equilibrium. When equilibrium is established [C]=0.75 M. Calculate all equilibrium concentrations. Calculate K.
I am so confused!

well, K

K=(a)(b)/(2C)^2 from the equation

A, and B will be half the C concentration..

K= .75^2/4 / 1.50^2

now you have K.

If C=.75, then A and B both used up .75/2

Which means the original-used is the now concentration

A=1M-.75= you do it
B=1.4M-.75= you do it
in the above, remember volume is 2L