The vapor-phase hydration of ethene to produce ethanol is represented below

CHEMISTRY · Multi-part · A Level · Chemistry · Thermodynamics · Thermodynamics

Problem

The vapor-phase hydration of ethene to produce ethanol is represented below.

\text{C}_2\text{H}_4(g)+\text{H}_2\text{O}(g)\rightarrow\text{C}_2\text{H}_5\text{OH}(g)

Standard molar free energies of formation at

298\,\text{K}

are provided.

\begin{array}{lcl}\text{Species}&&\Delta G_f^\circ\,(\text{kJ mol}^{-1})\\\text{C}_2\text{H}_4(g)&&+68.1\\\text{H}_2\text{O}(g)&&-228.6\\\text{C}_2\text{H}_5\text{OH}(g)&&-174.8\end{array}

(a) Determine the standard free-energy change

\Delta G^\circ

for the hydration reaction at

298\,\text{K}

. (b) Using your result from part (a), calculate the equilibrium constant

K

298\,\text{K}

. (c) A sealed vessel at

298\,\text{K}

initially contains only

1.00\,\text{mol}

\text{C}_2\text{H}_4

and

1.00\,\text{mol}

\text{H}_2\text{O}

at a total pressure of

1.00\,\text{atm}

. No ethanol is initially present. Based on the value of

K

from part (b), estimate whether conversion of ethene to ethanol is less than

10\%

, between

10\%

and

90\%

, or greater than

90\%

. Justify your choice quantitatively.