19 posts on chemistry. All posts · RSS feed
Carbon dioxide () dissolves in water, and some of the dissolved forms carbonic acid, : This acid can then dissociate to form bicarbonate, : which may further dissociate to carbonate, : The degree of dissociation (the equilibrium constants for the above processes) determines the distribution …
The Belousov-Zhabotinsky (BZ) reaction is a classical example of a non-equibrium chemical oscillator in which the components exhibit periodic changes in concentration. The model The BZ reaction mechanism is complex and still not fully understood, but its essential features can be captured in a simple …
The temperature-dependence of the rotational contribution to the heat capacity of gaseous molecular hydrogen shows a Schottky anomaly: whereas for many systems the heat capacity can be expected to increase with increasing temperature, for there is an temperature range within which it reaches a maximum …
It is a standard result of statistical thermodynamics that the molar heat capacity at constant volume, , is related to the molecular partition sum, , through the relation where and represent the first and second derivative of with respect to the "thermodynamic beta", : There …
The problem of predicting the term symbols for states derived from a atomic configuration (without using group theory!) provides a good use of Python's collections and itertools libraries. The function below can be passed the orbital angular momentum quantum number, , and number of electrons, …
The van der Waals equation of state for a gas is: in terms of the pressure, , molar volume, and temperature, . and are constants which depend on the gas, so it is often useful to recast this equation into reduced form: or equivalently where …
A binary regular solution is one in which the two components, A and B, mix with an entropy of mixing given by the ideal solution model, but have a non-zero enthalpy of mixing given by the relation where is a parameter describing the difference between …
The Cambridge Crystallographic Data Centre is a non-profit organisation devoted to small-molecule crystallography data. It curates, validates and distributes the Cambridge Structural Database (CSD) of over 800,000 organic and metal-organic crystal structures. The CSD has an excellent Python API which can be used to analyse …
A simple model of a polymer in solution treats its monomer units as totally uncorrelated in position (each monomer unit adopts a random orientation with respect to all the others): this is the random flight model. In the following code, a random flight polymer with …
