Thermaldynamically or kinetically stable?

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In summary, the individual is seeking advice on how to calculate the free energy and stability of certain compounds, specifically dihydrogen phosphites. They are having difficulty finding information in physical chemistry handbooks and are asking for guidance on obtaining entropy and free energy information. Suggestions include consulting Barin's Thermochemical properties of inorganic substances and Lange's Handbook of Chemistry for specific values.
  • #1
solidacid
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hi
I have a question about thermodynamic and kinetic stabiliy. for the general materials we can calculate the free energy and k for evaluation of thermaldynamical and kinetical stabiliy. however, for some strange compond, it is impossible to find the enthalpy and entropy to calculate the fre energy.

so could someone give me a advice to solve this problem?

thank you
!
 
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  • #2
Can you be more specific, if you're talking about a certain compound? Maybe someone here has experience working in that area.

There are two ways to get detailed energy and entropy information about a new compound: perform experiments and run simulations.
 
  • #3
Mapes said:
Can you be more specific, if you're talking about a certain compound? Maybe someone here has experience working in that area.

There are two ways to get detailed energy and entropy information about a new compound: perform experiments and run simulations.

Thanks a lot.
my material is dihydrogen phosphites e.g. NH4H2PO3 and KH2PO3. Phosphites are widely used as furtilizers, so few people are interested to their thermo properties. Even I checked several physical chemistry handbooks while no useful information was found. :(

could you give me more detials how to get the entropy or free energy information?
 
  • #4
Try Barin's Thermochemical properties of inorganic substances (H=-1568 kJ/mol, S=134.9 J/mol-K for potassium dihydogen phosphate) and Lange's Handbook of Chemistry (H=-1445 kJ/mol, S=152.0 J/mol-K for ammonium dihydogen phosphate).
 

Related to Thermaldynamically or kinetically stable?

1. What is the difference between thermodynamically and kinetically stable?

Thermodynamically stable refers to a state where a system has reached its lowest possible energy level, while kinetically stable refers to a state where the system is not likely to undergo any chemical reactions at a certain temperature.

2. How do you determine if a system is thermodynamically stable?

A system is considered thermodynamically stable if its free energy is at its minimum and its entropy is at its maximum. This means that the system has reached a state of equilibrium and will not spontaneously undergo any changes.

3. Can a system be thermodynamically stable but not kinetically stable?

Yes, it is possible for a system to be thermodynamically stable but not kinetically stable. This means that while the system may have reached its lowest energy state, it is still able to undergo chemical reactions at a certain temperature.

4. How does stability affect the rate of a chemical reaction?

A system that is thermodynamically stable will have a slower rate of reaction compared to a system that is kinetically stable. This is because a thermodynamically stable system has a lower energy barrier for reactions to occur, while a kinetically stable system has a higher energy barrier.

5. What factors can affect the stability of a system?

The stability of a system can be affected by factors such as temperature, pressure, concentration, and the presence of catalysts. These factors can alter the energy levels and the likelihood of chemical reactions occurring within the system.

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