In: Chemistry
The criterion for a spontaneous chemical reaction is:
a) ΔrG < 0 |
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b) ΔrS = 0 |
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c) ΔrH > 0 |
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d) ΔrG = 0 |
The criterion for sponataneous chemical reaction depend upon
G but not
H, and
S.
Enthalpy: H = -ve,
spontaneous
H = +ve,
non-spontaneous
H = 0,
equillibrium
but it is not criterion for spontaneous process in all cases
Entropy: S = +ve,
Spontaneous
S = -ve,
non-spontaneous
S = 0,
Equilibrium
but it is not criterion for spontaneous process in all cases
So, Gibbs freeenergy is introduced to explain spontaneity
G =
H -
T
S
Gibbs freeenergy:
G = -ve,
spontaneous
G = +ve,
non-spontaneous
G = 0,
Equilibrium
So, by using Gibbs freeenergy is used to explain spontaneity of reaction by combining both enthalpy and entropy in all cases at all temperatures and pressures