The change in Gibbs free energy `(DeltaG)` of the system along provides a criterion for the spontaneity of a process at constant temperature and pressure. A change in the free energy of a system at constant temperature and pressure will be:
`DeltaG_("system")=DeltaH_("system")-TDeltaS_("system")`
At constant temperature and pressure:
`DeltaG_("system")lt0` (Spontaneous)
`DeltaG_("system")=0` (equilibrium)
`DeltaG_("system")gt0` (non-spontaneous)
Free energy is related to the equilibrium constant as:
`DeltaG^(@)=2.303RTlog_(10)K_(e)`.
Q. A reaction has positive values of `DeltaH and DeltaS`. From this you can deduce that the reaction:
A. must be spontaneous at any temperature.
B. cannot be spontaneous at any temperature.
C. Will be spontaneous only at low temperature
D. will be spontaneous only at high temperature.
