Looking for a Name/Title

[John L]

There is a scientific title for the principle, in chemistry, that the more of a substance one adds to any given volume, the less it influences the volume statically as the saturation point increases.

 

A good example is the addition of CO2 into the atmosphere. At a certain point, 1a amount will result in say 1b change in the equation. But double the amount to 2a, and the result will not be 2b, but something less. Keep adding CO2, and the effect will continue to decrease to the point where any further addition will result in no noticeable change.

 

What is the name of this process? I just cannot remember it, sorry.

 

And thanks.

 

John

[CaptainPanic]

It might have something to do with excess properties (excess volume, excess enthalpy, excess entropy or excess Gibbs energy)? The excess properties are zero in ideal solutions, and are important in non-ideal situations.

 

I am not sure I answered your question, because gases (like the atmosphere) behave quite ideally, which means that in the gas phase the excess properties are (practically) zero, and properties change linearly with concentration. The excess properties are usually only defined for the liquid phase.

[John L]

No, there is a specific name for this. The more one introduces a substance into a mix, the less the influence as that amount increases. That is exactly why the view that increased CO2 into the atmosphere will keep increasing heat into the mix.

 

I just want to know the scientific name of this principle.

[Cap'n Refsmmat]

Saturation of some kind?

[A Tripolation]

I'm also thinking along the lines of supersaturation. I think that fits.

[ewmon]

Do you mean the law of diminishing returns, although I haven't heard it used to refer to a chemical process, it could be appropriate?

[mississippichem]

Activity?

[John L]

No, there is a scientific phrase for it. I just can't remember it, and it's driving me crazy.

[CaptainPanic]

No, there is a scientific phrase for it. I just can't remember it, and it's driving me crazy.

Well... you're in good company. You already got an answer above from chemists and chemical engineers. And it seems they also don't know.

 

Are you very very sure that your scientific phrase is something that applies to the gas phase too?

The fact that you search for something that's CO2 related in the atmosphere suggests that you want to learn something about absorption or something, but absorption (the laws of Lambert-Beer) are linear with the concentration of a certain material (including CO2).

[mississippichem]

Hmm...trying to narrow this down. Does this have anything to do with a thermodynamic potential function like Gibbs energy, Hemholtz energy, or maybe even the grand potential? Or is it some spectral phenomenon like Captain Panic mentioned?

[John L]

It's just basically a chart, with units of a substance on one side, and the change in effect on the other.

 

Again using CO2, as the amount of CO2 is introduced into the environment, the saturation curve moves upward. But as the CO2 increases, the effect begins to level off, to the point where the more CO2 introduced, the more horizontal the curve becomes. Eventually, the more CO2 introduced, the curve stops moving upward, being level.

 

As I have stated, there is a name for this type of effect. I just cannot remember it anymore, and would like to find it again. And it doesn't have to be CO2: it can be practically any gas.