The fermentation of sugar (C6H12O6) to form ethanol (C2H5OH) and carbon dioxide (CO2) occurs according to the following equation:
C6H12O6(aq) ¡ú 2 C2H5OH(aq) + 2 CO2(g)
kJ mol¨C1
¦¤Hf (C6H12O6(s))
is ¨C1275
¦¤Hf (C2H5OH(l))
is ¨C277
¦¤Hbond (C=O)
799
(a) Assuming the heat of dissolution of C6H12O6(s) and C2H5OH(l) in water are negligible, calculate an approximate value for the enthalpy for the above reaction.
(b) An approximate value for the entropy change, ¦¤S, for this reaction is +376 J K¨C1 mol¨C1. Comment on the sign and magnitude of this value and calculate values for the Gibbs free energy, ¦¤G, and the equilibrium constant, K at 298 K.
(c) State under what conditions this reaction is spontaneous.