What is Chemical Potential?

Chemical potential is a key concept for establishing the fundamental equation of thermodynamics. In this video, I explain the physical meaning of chemical potential and how it relates to Gibbs free energy.

[@LongQingChenPennState]

Really appreciate the beautiful and clear delivery of the concept of chemical potential by Prof Mauro. The introduction of chemical potential in this video doesn’t involve any calculus, so in principle, it can be used to introduce the concept of chemical potential to middle/high school students when the more familiar concepts of gravitational potential, electrical potential, temperature, and pressure are introduced in science/physics/chemistry classes. Perhaps this will help the students to become more comfortable with the concept of chemical potential when later on they are taking general chemistry, physical chemistry or thermodynamics classes in college.

[@johnmauro1230]

Thanks so much for very kind comment, Prof. Chen! All the key insights here are yours. 😃

[@nurfauziabdillah]

By far the easiest video to understand about chemical potential, many thanks!

[@johnmauro1230]

I'm so happy you enjoyed the video! Thanks for your kind comment.

[@husaainrabbani4305]

thanks for such a wonderful lecture. watched it twice, I am a new researcher in the field of Metamorphic petrology and currently working on Geobarometers. This video has made my concepts related to Gibbs free energy more clearer.

[@johnmauro1230]

I'm so glad the video was helpful to you. Thanks so much for your kind comment! Sending best wishes.

[@RLPW-y9p]

The Best explanation I've ever seen in the simplest way. Thank you very much for your valuable gem(I couldn't find the better word for what you've given).
Feeling Grateful.

[@johnmauro1230]

Wow, you made my day! Glad you found this explanation helpful. Thanks so much. 🙏

[@RLPW-y9p]

Please make a video on fugacity and activity too!!!🙏😇

[@baharkheilnezhad5329]

Thanks! I always had trouble deeply understanding this concept, but now I get it!

[@johnmauro1230]

I'm so happy to hear this!

[@domyforsale5485]

Many thanks for the video. I work in the area of cognitive linguistics/semantics.
In my opinion, your explanation is so effective because it appeals to the ways humans think. Note that all forms of energy in your video are defined as products of nested levels and concatenated layers. For example, POTENTIAL = ENERGY / MATTER means that ENERGY = POTENTIAL (levels) x MATTER (layers) where potential represents an intensive non-additive property and an extensive stands for additive property. This is not that different from, for example, the sensation of pain (which can be described as the product of pain intensity and its extent) or the experience of a colour, which can be described as the product of the intensity of red and its extent in space, and so on.
In thermodynamics and engineering, the pattern is confined to dyads such as intensive-extensive properties, effort-flow variables, force-displacement and across-through conjugates, or more generally cause-effect. In economics, the same pattern appears under names such as intensive and extensive production systems, margins, and growth as well as the value and volume of products and the cost and value of sales. Identical patterns can be found in education in the way people talk about the magnitude and multitude of quantities and dependent and independent variables.
In natural language, such pairs as adjective (bright red) and noun (e.g., apple’s volume) or extremely fast car provide the basis for sentences and narratives. More examples could be found in the articles “Layers and Levels: What a Column of Water Tells Us about Human Cognition” and “From Sensations to Contrast, Opposition and Numbers,” among others.
Note that every such pair represents two distinct ways of thinking. The first term denotes causes (e.g., force, tension or effort of some magnitude), while the second term draws attention to the effects (e.g., displacement, extension, or flow of some extent). What is curious is that the members of those dyads are neither opposed to nor align with each other but are in an orthogonal relationship. When associated together (multiplied), those two patterns give rise to products.
In your video, internal energy, itself a product, is the sum of products such as thermal, mechanical and chemical energy. Looking forward to more videos like this one.
Wes.

[@johnmauro1230]

Thanks so much, Wes! I really appreciate your kind comment and the connections that you are making to these other fields of study. Very fascinating!

[@domyforsale5485]

Thank you for acknowledging my comment.
I find the idea of adding different forms of energy together to arrive at the total internal energy both perplexing and exciting. It is like adding apples to oranges.
From both cognitive and mathematical perspectives, one can only add products of the same properties (e.g., color red) with identical intensity (bright red ). For example: (10 square cm of bright red) + (5 square cm of bright red) = bright red (10cm² + 5cm²) = bright red (15cm²) = bright × 15cm² = final product
The statement U = Ut + Um + Uc appears to contradict dimensional analysis, unless we consider the First Law of thermodynamics. This fundamental law, stating that the energy of the universe is constant, allows us to "add" different dimensions together as they represent the same property (energy). This also makes it possible to interpret entropy as a kind of matter and provides a logical structure for thermodynamics.
If you wish to contact me directly, please refer to the article 'From Sensations to Contrast, Opposition and Numbers' for the latest email address.
Wes
@@johnmauro1230

[@johnmauro1230]

A couple of points from Dr. Long-Qing Chen regarding the use of "Gibbs (G)" as the unit for chemical potential. The origin of this proposed unit goes back to some earlier thermodynamics literature in Germany, where the suggestion first appeared. Also, one of the advantages of using a unique unit for chemical potential is to distinguish it from quantities like molar internal energy, molar enthalpy, and molar Helmholtz free energy, which are *not* potentials, so they have the unit of J/mol rather than G.

[@abhishekcp2024]

Thank you ❤❤❤❤, why nobody taught us like this in University.

[@johnmauro1230]

You are so kind. Thank you very much!

[@BumbleTheBard]

Nice presentation. I hadn't thought of entropy as a quantity of thermal matter before. It still seems a little strange. Presumably, if we wished to consider nuclear reactions as well, then nuclear energy would be a further component of the internal energy and it would have a nuclear potential defined similarly to the chemical potential.

[@johnmauro1230]

Thanks for watching and for your kind comment. For nuclear reactions we need to use the rest mass energy (U_o = mc^2) of the atoms/isotopes involved. In normal thermodynamics (without nuclear reactions), this doesn't need to be considered since it doesn't change during the course of the experiment. But for nuclear reactions this becomes by far the dominant term.

[@GandalfTheBrown117]

Very nice presentation! Was the slide deck made with LaTeX Beamer or Powerpoint?

[@johnmauro1230]

Thank you! I used PowerPoint for this. Have a nice day!

[@GandalfTheBrown117]

@@johnmauro1230 It looks beautiful. Hope you have a great one as well!

[@JC3335]

The chemical potential is composed via the calculation of two fundamental units whereas the other energies are directly measured in fundamental units. Thats why one cannot use a Gibbs unit. But it also suggests something - the chemical potential may not be a truly intrinsic measure.

[@johnmauro1230]

Thanks for watching the video and sharing your thoughts on the proposed Gibbs unit!