The variation of chemical potential with particle number is most easily expressed in terms relating quantities to their concentrations.
Thermodynamics is expressed by a mathematical framework of thermodynamic equations which relate various thermodynamic quantities and physical properties measured in a laboratory or production process.
I shall take the simpleminded view that a theory is just a model of the universe, or a restricted part of it, and a set of rules that relate quantities in the model to observations that we make.
In fact, the result of the calculations is that you find non-integer exponents relating various quantities in the system at the critical point (or near to it), somewhat similar to the non-integer dimensions of fractals.
The first require the thinker to relate quantities; the other require the transformation of the orientation of an object in space.
Very complex graph: the psychrometric chart, relating temperature, pressure, humidity, and other quantities.
For this reason it may not be correct to relate thermodynamic quantities obtained from one cooling curve to those obtained by another as has been pointed out by Gee (1966).
In physics, there are equations in every field to relate physical quantities to each other and perform calculations.
These are dualities between string theories which relate seemingly different quantities.
Because science and engineering often relate quantities to each other, the methods of related rates have broad applications in these fields.