Posted by Amber on .
At a particular temperature, K = 3.75 for the following reaction.
SO2(g) + NO2(g) <==> SO3(g) + NO(g)\
If all four gases had initial concentrations of 0.550 M, calculate the equilibrium concentrations of the gases.

Chemistry 
DrBob222,
Since you gave concns in M, I assume the K given is Kc. First, calculate Qrxn.
Q = (SO3)(NO)/(SO2)(NO2) = 1 (you can plug in the numbers to see Q = 1. So Kc = 3.75 which means the reaction must move to the right to attain equilibrium.
..............SO2 + NO2 ==> SO3 + NO
initial.....0.550..0.550..0.550...0.550
change........x.....x........x....+x
final0.550x..0.550x..0.550+x 0.550+x
Substitute the final (equilibrium but I didn't have enough space to write that) into the Kc expression and solve for x, then evaluate 0.550+x and 0.550x.