According to thermodynamics,enthalpy change for spontaneous process should negative and entrophy change must be positive.It is observed during adsorption entrophy change is negative which suggests it,as a nonspontaneous process and thermodynamically should not be possible, but adsorption is spontaneous and thermodynamically possible. what maybe possible explanation of this?
Answers
Answer:
first law formula = DELTA Q = DELTA U + DELTA W
If ΔH is negative, and –TΔS positive, the reaction will be spontaneous at low temperatures (decreasing the magnitude of the entropy term). – If ΔH is positive, and –TΔS negative, the reaction will be spontaneous at high temperatures (increasing the magnitude of the entropy term).
In the quest to identify a property that may reliably predict the spontaneity of a process, we have identified a very promising candidate: entropy. Processes that involve an increase in entropy of the system (ΔS > 0) are very often spontaneous; however, examples to the contrary are plentiful. By expanding consideration of entropy changes to include the surroundings, we may reach a significant conclusion regarding the relation between this property and spontaneity
KEY's Equations:
- ΔS∘=ΔS∘298=∑νS∘298(products)−∑νS∘298(reactants)
- ΔS=qrevT
- ΔSuniv = ΔSsys + ΔSsurr
- ΔSuniv=ΔSsys+ΔSsurr=ΔSsys+qsurrT
- ΔG = ΔH − TΔS
- ΔG = ΔG° + RT ln Q
- ΔG° = −RT ln K
Explanation: