Questions related to mathematical chemistry which include application of mathematics to problems in chemistry and the development of mathematical methods suitable for such applications and for the formulation of chemical theories
Questions tagged [chemistry]
229 questions
30
votes
2 answers
(Organic) Chemistry for Mathematicians
Recently I've been reading "The Wild Book" which applies semigroup theory to, among other things, chemical reactions. If I google for mathematics and chemistry together, most of the results are to do with physical chemistry: cond-mat, fluids, QM of…
isomorphismes
- 4,758
28
votes
4 answers
Balance chemical equations without trial and error?
In my AP chemistry class, I often have to balance chemical equations like the following:
$$ \mathrm{Al} + \text O_2 \to \mathrm{Al}_2 \mathrm O_3 $$
The goal is to make both side of the arrow have the same amount of atoms by adding compounds in the…
Chao Xu
- 5,988
17
votes
8 answers
Why can't we remove the sqrt from rms?
In chemistry, we define the root-mean-square speed as
$\sqrt{\bar{u^2}}$ = $\sqrt{\frac{3\text{RT}}{\text{M}}}$
A student asked me why we can't just remove the square root symbol. And aside from "because this is how we define it", I didn't actually…
J M
- 401
12
votes
2 answers
An application of the Inclusion Principle to Chemistry? (Proof Verification)
Background
I’m taking chemistry and one thing they have us do is draw Lewis structures for molecules. Guessing if there are going to be double or triple bonds is kind of annoying. I’d like to be able to come up with a formula to predict the total…
Ahmed S. Attaalla
- 19,199
10
votes
2 answers
Are there different conventions for 'rounding to even'?
In my high school chemistry class, my teacher insists that the "round to even" rule means rounding to the nearest even number whenever the next digit is 5, regardless of any digits that follow. For example, she teaches that 2.59 should be rounded to…
Herbert The Bird
- 333
10
votes
1 answer
Application of Combinatorics/Graph Theory to Organic Chemistry?
Recently, I have been self-teaching graph theory and having an organic chemistry course at school.
When I was learning isomer enumeration I found great resemblance between organic molecules and graphs. Every atom can be regarded as a vertex, with…
Yuxiao Xie
- 8,972
10
votes
1 answer
Why is $\arccos(-\frac 13)$ the optimal angle between bonds in a methane ($\rm CH_4$) molecule?
Background: In a CH4 molecule, there are 4 C-H bonds that repel each other. Essentially the mathematical problem is how to distribute 4 points on a unit sphere where the points have maximal mutual distance - or, how to distribute 4 position vectors…
986
- 1,438
7
votes
2 answers
Asimov quote about "eight million trillion" arrangements of amino acids
A friend of mine is subediting a book whose author died in 1999. The author, at some point, uses the word "trillion" which is, unfortunately, an ambiguous word in the UK: when I was at school it used to mean $10^{18}$ but nowadays it means…
Kevin Buzzard
- 4,908
7
votes
0 answers
Solving two electron integral
During one of my practical courses we had to do the Hartree-Fock-method "by hand". Part of that was to calculate the occurring two electron integrals.
With $$\chi_i(r) = 2 \cdot \alpha_i^{3/2} e^{-\alpha_i r} Y_0^0$$
we were given the following…
6
votes
0 answers
mathematics of chemical stoichiometry
I would like to better understand the mathematical description of chemical stoichiometry and thermodynamic chemical equilibrium. This problem has many features and I know my description might be too vague.
There are generally two approaches to the…
jpantina
- 89
6
votes
0 answers
Deconvolution of distribution of diffraction reflexes
I'm a chemist stuck in a mathematical problem. Please bear with me as I'm trying to express myself in Math language.
Let me explain in short terms the experimental method I'm using: X-ray diffraction. For this method, atoms in a solid can be viewed…
Christian
- 61
6
votes
2 answers
Counting trees with constraint on degree of vertices
How many different trees are there with $(n-1)$ red vertices and $1$ blue vertex, such that the blue vertex has degree less than or equal to $3$, and each red vertex has degree less than or equal to $4$? Derive an explicit formula if possible.
The…
youthdoo
- 3,663
6
votes
1 answer
Symmetry group of an hourglass shape, the molecule Ferrocene.
I am starting to learn (Visual) Group Theory and I saw this hourglass shaped molecule Ferrocene:
I am wondering what group is described by its symmetries. On top of the five rotations I think there are vertical $v$ and horizontal $h$ flips. Mapping…
Pierrick Leroy
- 137
6
votes
1 answer
Determining whether or not a system of equations has positive integer solutions
Consider the chemical reaction:
$$ \mathrm{ClO_3} + \text I_2 \to \mathrm{Cl} + \mathrm {IO_3} $$
When given the reaction in a test, I did not know whether I was meant to balance it by manipulating the coefficients or to balance it using chemical…
Fouad Saffar
- 176
- 8
6
votes
0 answers
Quantum Chemistry book recommendation.
I am trying to learn quantum chemistry. I have an extensive background in math and physics, so I'm looking for a book that makes full use of whatever physics and mathematics is relevant to this subject, although I'm not sure if such a text even…
goling onner
- 69