Question

Heats of reaction calculated from bond energies and from heats of formation are often, but not always, close to each other.a. Industrial ethanol (CH3CH2OH) is produced by a catalytic reaction of ethylene (CH2=CH2) with water at high pressures and temperatures. Calculate ΔHºrxn for this gas-phase hydration of ethylene to ethanol, using bond energies and then using heats of formation.b. Ethylene glycol is produced b the catalytic oxidation of ethylene to ethylene oxide, which then reacts with water to form ethylene glycol:image from custom entry tool + H2O (l) = HOCH2CH2OH(l)The ΔHºrxn for this hydrolysis step, based on heats of formation, is -97 kJ/mol. Calculate ΔHºrxn for the hydrolysis using bond energies.c. Why are the two values relatively close for the hydration in part "a" but not close for the hydrolysis in part "b"?

Answer 1

Answer:

45.7kj

Explanation:

To calculates the heats of reaction from heats of formation:

∆Hr=£∆Hp -£∆Hr

= £∆Hch3ChOH - £∆HCh2h2+h20

=(-235.1kj)-(+52.47kj/kg + (-241.8kj/kg)

∆H = 45.71kj/kg