Fugacity: Definition & Intuitive Sense

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R.In summary, fugacity is the corrected pressure used for non-ideal systems to convert ideal gas equations into more useful equations. It is also known as the "intuitive sense" of pressure as it represents the pressing in against a surface. It is used to determine the change in Gibbs free energy at constant temperature and is often preferred over pressure in non-ideal gas situations.
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alighazanfer25
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What is fugacity ? I know it the corrected pressure for non ideal systems , but I need a much more intuitive sense of the term. It would be nice to get some help on this...
 
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The intuitive sense for it is "pressure" - a pressing in against a surface.
It's basically a way to convert ideal gas equations into equations more useful for real gasses.
 
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alighazanfer25 said:
What is fugacity ? I know it the corrected pressure for non ideal systems , but I need a much more intuitive sense of the term. It would be nice to get some help on this...

For an ideal gas, VdP = RT d lnP

For a real gas, we use an equation of the same form to express VdP:

VdP = RT d ln f

where f is the fugacity. This is used to determine the change in Gibbs free energy dG = VdP at constant temperature. So dG = RT d ln f. In practice, it is easier to work in terms of the fugacity than the pressure when working in the non-ideal gas region.

Chet
 

What is fugacity?

Fugacity is a measure of the tendency of a substance to escape or flee from a system. It is also referred to as the escaping tendency or escaping tendency coefficient.

How is fugacity related to pressure and temperature?

Fugacity is directly proportional to pressure and inversely proportional to temperature. As pressure increases, fugacity also increases. However, as temperature increases, fugacity decreases.

What is the difference between fugacity and partial pressure?

Fugacity takes into account the non-ideality of a substance, while partial pressure assumes ideal behavior. This means that fugacity is a more accurate measure of a substance's escaping tendency in a real system.

How is fugacity used in thermodynamics?

Fugacity is used in thermodynamics to calculate the equilibrium conditions for a non-ideal system. It is also used in the calculation of chemical potential, which is an important property in determining the thermodynamic stability of a system.

How is fugacity measured?

Fugacity cannot be measured directly, but it can be calculated using equations such as the fugacity equation or the Van der Waals equation. It can also be estimated using experimental data and empirical correlations.

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