At a particular temperature, K = 3.75 for the following reaction.

Question

SO2(g) + NO2(g)= SO3(g) + NO(g)

If all four gases had initial concentrations of 0.840 M, calculate the equilibrium concentrations of the gases.

Answer 1

K= (.84+x)^2 /(.84-x)^2

take the square root of each side, then

sqrtK=(.84+x)/(.84-x)
and you can multipy both sides by .84-x and then solve for x.
Knowing x, you can then find the concentration of each product (either add or subtract x from .84)
check my thinking.

Answer 2

K = [SO3][NO / [SO2][NO2]] = 3.75
Let the moles of each reactant = x
[0.840+x][0.840+x] / [0.840-x][0.840-x] = 3.75
a) Solve for x.
b) To get the concentration of each reactant, subtract the value of x from 0.840M.
c) To get the concentration of each product, add the value of x to 0.840M.