Answer to Question #193143 in Chemistry for John

Question

This question is on equilibrium.

(a) Many chemical processes release waste products, such as carbon dioxide into the atmosphere. Scientists are developing new catalysts to convert these emissions into useful products, such as fuels.

CO₂(g)+ 3H₂(g) ⇌ CH₃OH(g) + H₂O(g) ∆H = −49 kJ mol^-1

(i) Use Le Chatelier’s principle to explain why the reaction is carried out at a

high pressure rather than at atmospheric pressure.

(ii) A copper catalyst is employed to speed up the reaction, but it does not have any effect on the position of equilibrium. Explain why.

                   

(iii) The reactions is carried out at low temperatures 270-280 K. Explain why this is ideal in terms of the equilibrium

Answer 1

i) The reaction given is an exothermic reaction (∆H =). As a result, If the pressure increases, the equilibrium position moves to the right, increasing the yield of the products.

ii) Catalysts do not affect the reaction equilibrium since the same amounts of reactants and products will be present at equilibrium In the presence of a catalyst.

iii) Since heat is the product of the exothermic reaction, at low temperatures the equilibrium will shift to the right increasing the yield of the reaction.