Role of pressure and temperature in chemical reactions

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SUMMARY

The discussion centers on the influence of pressure and temperature on chemical reactions, particularly between gases. It is established that elevated temperatures can enhance reaction kinetics and shift equilibrium, but they are not strictly necessary for a reaction to occur. High pressure can also facilitate reactions, especially when combined with low temperatures, challenging the notion that temperature is the sole driving factor. The concept of Gibbs free energy (ΔG) is highlighted as a critical metric for assessing reaction feasibility, even in cases where product formation is minimal.

PREREQUISITES
  • Understanding of chemical kinetics and thermodynamics
  • Familiarity with the concept of Gibbs free energy (ΔG)
  • Knowledge of gas laws and their implications in chemical reactions
  • Experience with equilibrium constants and their calculations
NEXT STEPS
  • Research the role of catalysts in chemical reactions and their effects on kinetics
  • Study the principles of Le Chatelier's principle in relation to pressure and temperature changes
  • Explore the calculation of Gibbs free energy (ΔG) for various chemical reactions
  • Investigate specific examples of gas-phase reactions under varying pressure and temperature conditions
USEFUL FOR

Chemists, chemical engineers, and students studying reaction dynamics who seek to understand the interplay between pressure, temperature, and reaction kinetics.

physea
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Hello!

I have a feeling and I would like to know if it is true.
I feel that if a reaction between two gases, takes place in high temperature only (perhaps with the presence of a catalyst), then if we increase the pressure high enough and keep the temperature low, the reaction may still take place.

In other words, I think that it is quite equivalent the effect of increased temperature and increased pressure in the kinetics of a chemical reaction.

Is that true?

Can you give me an example of such reactions?

Thanks!
 
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At this level of a handwavy generalization the answer is: yes, no, maybe.

Technically yes, elevated temperatures are used to either speed up the reaction (kinetic factor) or to move the equilibrium to the right (thermodynamic factor) to make the reaction practical, but there is nothing that makes them absolutely necessary.

However, if the amount of products at equilibrium present in the mixture is below a single molecule per mole of reactants, do you consider it to mean "reaction took place"? I don't have an example at hand, but it is not difficult to calculate ΔG for such a reaction from estimates of equilibrium constants and it will be in a reasonable range (as in: yes, we know reactions with such ΔG).
 
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