Question #edf1e

2 Answers
Aug 24, 2015

I assume you are looking for the final equilibrium concentrations of this reaction.

Explanation:

First, you must balance the chemical equation in order to get the coefficients needed for the rate reaction:

2N_2 + O_2 rightleftharpoons 2N_2O2N2+O22N2O

Then you need to set up an ICE (Initial, Change, Equilibrium) chart to find the factors that need to be solved in the equation for a numerical result:

N_2 = "0.482 Mole"N2=0.482 Mole, O_2 = "0.933 Mole"O2=0.933 Mole K_c = 2 xx 10^(-37)Kc=2×1037

The volume is irrelevant as long as the molar quantities are known and it is a gas mixture. It is only necessary if you are given solution volumes and need to correct from the standard moles/Liter to actual moles in solution for liquid solutions.

" " " "2N_2" " " " + " " " "O_2" " rightleftharpoons " " " "2N_2O 2N2 + O2 2N2O

"I" " " " " " " "0.482" " " " " " " " " "0.933" " " " " " " " " " "0I 0.482 0.933 0
"C" " " " " " " "(-x)" " " " " " " " " "( -0.5x)" " " " " " " " "(+x)C (-x) ( -0.5x) (+x)
"E" " " " " (0.482-x)" " "(0.933-0.5x)" " " " " " "(+x)E (0.482x) (0.933-0.5x) (+x)

(this is why you need to balance the equation, not all of the O_2O2 will be used)

The equilibrium equation is

K_c = (["Products"]^A)/(["Reactants"]^B)" "Kc=[Products]A[Reactants]B , where

AA and BB are the coefficients in the balanced chemical equation.

The equation for this system at equilibrium is thus:

2.0 xx 10^-(37) = ([N_2O]^2)/([N_2]^2 * [O_2])2.0×10(37)=[N2O]2[N2]2[O2]

Substituting the problem values from the ICE chart:

2.0 xx 10^(-37) = (x^2)/((0.482-x)^2 * (0.933-0.5x))2.0×1037=x2(0.482x)2(0.9330.5x)

Solve for xx to calculate the final concentrations of N_2N2, O_2O2, and N_2ON2O.

Sep 22, 2015

Also asked: Is this also how to calculate composition of equilibrium?
YES.

Explanation:

In general, the steps to determine the composition of an equilibrium mixture, given the chemical reaction equation, starting concentrations of the reactants, and the equilibrium constant are the same.

  1. Write out the balanced chemical reaction.
  2. Set up the I.C.E table to determine the equilibrium concentrations of each species.
  3. Use the values from the Equilibrium line of the ICE (including the unknown factors) to set up the equilibrium equation with the equilibrium constant.
  4. Solve the equation for the unknown quantity, then back-calculate any other species that may depend on that value (if necessary).