Ethanol can be manufactured by reacting ethene, C₂H₄, with steam.

C₂H₄(g) + H₂O(g) ⇌ C₂H₅OH(g)

a. Write the equilibrium expression in terms of partial pressures, K_p, for this reaction.

b. State the units of K_p for this reaction.

c. The reaction is at equilibrium at 290°C and 7.00 × 10⁶ Pa pressure. Under these conditions the partial pressure of ethene is 1.50 × 10⁶ Pa and the partial pressure of steam is 4.20 × 10⁶ Pa.

i. Calculate the partial pressure of ethanol.

ii. Calculate the value of the equilibrium constant, K_p, under these conditions.

d. The reaction is carried out in a closed system. Explain the meaning of the term closed system.

e. Use Le Chatelier’s principle to explain what will happen to the position of equilibrium in this reaction when the pressure is increased.

f. The results in the table below show the effect of temperature on the percentage of ethene converted to ethanol at constant pressure. Use this information to deduce the sign of the enthalpy change for this reaction. Explain your answer.