Identify the affect the equilibrium of the system on the following given situation.

Question

Consider the reaction that has reached a state of equilibrium at 200^oC:

CO_(g) + 3H_2(g) ⇌ CH_4(g) + H₂O_(g)   exothermic

 

Determine whether each of the following will increase the equilibrium concentration of CH₄ product. Explain your reasoning.

a. Remove H2O gas

b. Remove CO gas

c. Increasing the temperature of the system:

d. Decreasing the pressure in the reaction vessel:

Answer 1

This is a problem dealing with LeChatelier's principle, which essential says that

if a dynamic equilibrium is disturbed by changing the conditions, the position of equilibrium shifts to

counteract the change to reestablish the equilibrium.

CO_(g) + 3H_2(g) ⇌ CH_4(g) + H₂O_(g)   exothermic (heat is a product)

(a). If we remove H₂O(g): equilibrium will shift to the right (product side) in an attempt to replace the H₂O removed. This will also result in an increase in CH₄(g)

(b). If we remove CO(g): equilibrium will shift to the left (reactant side) in an attempt to replace the CO removed. This will result in a decrease in CH₄(g).

(c). If we increase the temperature: equilibrium will shift to the right (reactant side) in an attempt to remove the added heat. This is the case because the reaction is exothermic, meaning heat is given off, and so heat can be considered a product of the reaction. This will result in a decrease in CH₄(g).

(d). If we decrease the volume: A decrease in volume is equivalent to an increase in pressure since we are dealing with a system of gases. And with an increase in pressure, equilibrium will shift to the right (product side) because there are fewer moles of gas (2 mols) on the product side compared to mols of gas (4 mols) on the reactant side. This will result in an increase in CH₄(g).