Organic Chemistry
posted by Cerise .
CH2=CH2 +H2O <> CH3CH2OH
Delta H = 10.6 kcal/mol
Delta S = 30.3 cal/Kmol
why is delta S a negative value?

Not quite sure I understand the question.
If we go to the Gibb's free energy equation:
delta G = delta H  (T)(delta S)
where T is the temperature in kelvin
Remember that a more negative value of delta g is more spontaneous, and a large positive value of delta g is less spontaneous.
since both H and S are negative:
delta G = (H)  (T)(S)
delta G = (H) + (T)(S)
thus, the larger the value of T, the more positive the delta G... the LESS spontaneous...
Is this what you are after?