If we add CO2 to increase its concentration to 0.30 mol/L, what will the concentrations of all the gases be when equilibrium is reestablished?

Consider the following equilibrium process at 686 degree C:

CO2 (g) + H2O (g) >=> CO (g) + H2O (g)

The equilibrium concentrations of the reacting species are [CO] = 0.050 M, [H2] = 0.045 M, [CO2] = 0.086 M, and [H2O] = 0.040 M.

(a) Calculate Kc for the reaction at 686°C.

(b) If we add CO2 to increase its concentration to 0.50 mol/L, what will the concentrations of all the gases be when equilibrium is reestablished?

The answers to the question are

(a) 0.52

(b) The concentrations of the gases when equilibrium is reestablished will be

[CO₂] = 0.28 M

[H₂]  = 0.0295 M

[CO] = 0.068 M

[H₂O]  = 0.058 M

Explanation:

(a) To find we have to write out the expression for equilibrium as follows

(b) When the concentration of CO₂ is increase we have go over the previous step to check the reaction quotient as follows

Since Q < K the reaction is positive that is to go forward

The change in concentration of the reactants and products at equilibrium is given by x [CO₂] = [0.3 -x], [H₂] = 0.045 -x, [CO] = 0.05 + x and [H₂O] = 0.040+x

to solve for x we have

expanding and collecting like terms, we have

0.48x² +0.2694x-0.00502 = 0

factorising gives (x+0.579)(x-1.805)×0.48=0

x = -0.579 or x = 1.805×10⁻²

[CO₂] = (0.3 -1.805×10⁻²) = 0.28 M

[H₂] = 0.045 -x = 0.0295 M

[CO] = 0.05 + x = 0.068 M

[H₂O] = 0.040+x = 0.058 M

answer : one can design an experiment using a liquid and an additive that can be added to the liquid and observe the chemical changes in the reaction species.

one would need a beaker which is filled with a known amount of the liquid in which thermometer is placed to measure the temperature changes; after addition of the additive to the liquid solution one can note down the temperature change and find whether the reaction is endothermic or exothermic in nature. by subtracting the initial temperature value with the final temperature one can find the temperature changes.

various combinations of liquid and additive can be used. liquid in this case can be a known quantity of water and additives can be epsom salt or without epsom salt the experiment can be conducted to notice the changes. water and ice, hydrogen peroxide and dry yeast, vinegar and baking soda,etc.