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

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15 views

How to define boundary conditions for a sphere to run reaction-diffusion equations on its surface?

I'm in a Biology lab, and we managed to simulate reaction-diffusion equations on a torus using periodic boundary conditions for a 2D matrix. We want to try doing the same on a sphere, but I'm a ...
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1answer
32 views

Chemical kinetics using Laplace transformation

I have a simple chemical reaction $A\leftrightarrow B$ with forward rate $k_1$ and backward rate $k_2$. I can now write the differential equation of this system as following. $ \frac{dA}{dt} = -k_1A ...
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2answers
45 views

N2 diffusion through a vertical fluid column

Trying to figure out the mathematical model that might correlate to laboratory results. I have a cylindrical pressure vessel (picture a can) with height, h, and radius, r. It is filled with distilled ...
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0answers
16 views

Birth-coagulation process

I'm reading a paper where the birth-coagulation process is described as: $$ A \rightarrow A+A ;\, \text{rate:} \gamma $$ $$ A + A \rightarrow A ;\, \text{rate:} \chi $$ The total density of ...
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0answers
36 views

Why does an infinite Neumann boundary condition become a Dirichlet condition?

Often when I read a paper I see a statement of the type: Our boundary condition at the surface is $\frac{\partial f}{\partial x} = \alpha$. In the limit of $\alpha \to \infty$ this is equivalent ...
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1answer
52 views

Formula for $P\small CO_2$

Not really sure where I was supposed to ask this question. I have no background/knowledge in chemistry or math of this level. This is a follow-up question from my question over at StackOverflow ...
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2answers
51 views

Problem approximating for a chemical problem:

Solve using suitable approximation by hand: $$s(s-\alpha)=5\times10^{-13} \\ \frac{\alpha}{(s-\alpha)(0.4-2\alpha)^2}=10^8$$ Now to solve this I tried assuming $s\approx\alpha\approx0.2$ and then ...
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1answer
57 views

Model a chemical phenomenom

I have a chemical phenomenon to model for my research. I'll try to be clear while explaining my problem. I created little molecules (let's call them "emitters"), which emit a signal. When the ...
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1answer
29 views

Modelling an energy profile with/without catalyst

I'm trying to make a data table that can be plot to model the energy profile of a chemical reaction with/without catalyst. example image This is essentially what I want to plot, and I'm at a loss for ...
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1answer
98 views

Examples of applications of category theory to chemistry

What is some simple application of category theory to chemistry, namely, something that is much easier to do in chemistry with category theory than without. It does not need to be bleeding edge, or to ...
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1answer
53 views

How would chemical equations be balanced with matrices?

For example, I have this equation: KMnO4 + HCl = KCl + MnCl2 + H2O + Cl2 Then I get this: a * KMnO4 + b * HCl = c * KCl + d * MnCl2 + e * H2O + f * Cl2 K: a = c Mn: a = d O: 4a ...
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1answer
60 views

Nonlinear Dynamics and Chemical Reactions (Ivanova Reaction System)

I have a homework problem in which I'm given an Ivanova reaction system $X+Y \longrightarrow 2Y$, $Y+Z \longrightarrow 2Z$, $Z+X \longrightarrow 2X$, and I'm asked to write the mass-action ODEs ...
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1answer
65 views

physical meaning of heat equation

consider the heat equation $u_t=a(t)u_{xx}+f(x,t)$, $0<x<L$, $0<t<T$ subject to the initial condition $u(x,0)=g(x)$ and boundary conditions $u(1,t)=0,$ $u_x(0,t)+hu(0,t)=0$ where ...
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3answers
58 views

A lab worker needs $5$ litres of $20\%$ alcohol solution.

A lab worker needs $5$ litres of $20\%$ alcohol solution. A $10\%$ solution is mixed with a $60\%$ solution. How many litres of the $60\%$ solution will be required?
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31 views

Mathematical treatment of mass action kinetics with detailed balance (as opposed to complex balance)

I'm looking for a mathematical treatment of mass action kinetics under the assumption of detailed balance. In particular, I'm interested in the proof that the free energy is a global Lyapunov ...
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2answers
1k views

Easiest way to solve system of linear equations involving singular matrix

I am trying to balance an unbalanced chemical equation by using setting up a system of linear equations to solve for the stoichiometric coefficients in the chemical equation. After setting up a ...
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2answers
45 views

How to find the number of atoms of an element in $x$ amount of a compound

Lets say I am given a certain mass of a compound. Additionally, the number of moles of the compound itself are known, as well as its molar mass. How can I, using an equation, find the number of atoms ...
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0answers
217 views

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 ...
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1answer
66 views

What does the $-1$ mean in $2\mu g/L^{-1}$

What does the $-1$ mean in the expression $2\mu g/L^{-1}$? Does it literally mean multiply by $-1$?
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2answers
40 views

Significant Figures

I have learned in class that to subtract decimal numbers and keep significant figures, one just lines up the decimal, then rounds the answer according to the operand with the fewest places after the ...
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0answers
57 views

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 ...
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1answer
104 views

Differential equation based on chemical kinetics

In chemical equations, rate laws have the following form: $$r=kx^ay^b$$ ...where $r$ is the time derivative of either $x$ or $y$ times a constant: $$r=-\frac{dx}{\beta dt}=-\frac{dy}{\gamma dt}$$ ...
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4answers
282 views

Can exact numbers be written in scientific notation

I've learned in scientific notation you have last number as probable. Meaning it could be anything... so in $3$ significant digit number such as follows $3.34$ has '$4$' which could be anything. ...
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1answer
77 views

Calculate terminal half life and build up

Trying to solve this from a different approach now. started out here Calculate half life of esters Is there a way to find a function that fits the graph below? There are a few criterions. The ...
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0answers
132 views

Calculate half life of esters

I'm trying to calculate the level of testosterone released from different testosterone esters. Here are some graphs of testosterone levels after single injections of 250mg of each ester. Testo U ...
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25 views

Calculate half life of esters [duplicate]

edit - wrong part of stack exchange
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1answer
61 views

Diluting a $0.5M$ solution to $0.1M$

Using the $0.5 M$ solution how will you prepare a solution of $0.1 M$? Glassware provided is $3$ volumetric flasks of size $500, 250$ and $100 ml$. All bulb pipettes are provided and the sizes are ...
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1answer
222 views

Change of variables in Belousov-Zhabotinsky reaction

Here I am referring to http://demonstrations.wolfram.com/TheBelousovZhabotinskyReaction/, but not only this. If you press "Download demonstration as CDF" (implying you have the necessary tools to open ...
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3answers
330 views

Pólya's Enumeration formula and isomers

The hydrocarbon benzene has six carbon atoms arranged at the vertices of a regular hexagon, and six hydrogen atoms, with one bonded to each carbon atom. I know that two molecules are said to ...
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1answer
406 views

Pólya’s Enumeration Theorem and chemical compounds

The hydrocarbon naphthalene has ten carbon atoms arranged in a double hexagon, and eight hydrogen atoms attached at each of the corners of the hexagons. Naphthol is obtained by replacing one of ...
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1answer
154 views

Function whose graph resembles the shape in this image

What is the function whose graph would resemble the shape found in the image below? I looked this up on Wikipedia, tried making my own, but I can't find an equation the Electromagnetic Spectrum. I ...
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3answers
1k views

How to find the ratio for a combination of two chemical solutions

Lets say you have a chemical solution $A$ that has a ratio of $4:1$ of water to some chemical substance, and a solution $B$ that has a ratio of $9:1$ of water to some other chemical substance. If ...
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1answer
344 views

Finding the number of combinations of numbers taken 3 at a time, but with a twist

The twist is that each number should be 'associated' with at most K other numbers. Let me explain 'association' with an example: Notation: (1 A 2) means 1 is associated with 2, and (1 A 2) is ...
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1answer
127 views

Is it possible to balance a chemical equation without using trial and error? [duplicate]

Possible Duplicate: Balance chemical equations without trial and error? Thanks Ben, the other answer was helpful... but is it possible to do it when, say, five variables are involved? ...
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1answer
160 views

Geometry and chemistry

There's a really obvious geometric reason why the cosine of the bond angle in graphite is $-1/2$: the stuff consists of sheets shaped like honeycombs. There's also a really obvious geometric reason ...
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2answers
423 views

how to calculate n-percent solution given impure chemical?

I couldn't find a stackexchange site for computational chemistry, so hope this is apropos for this forum: I can get 80% pure sodium chlorite and I want to make a 28% solution of it. Though I'm ...
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1answer
295 views

Fourier (Hankel?) transform of a discrete set of radial points (question from a chemist!)

I'm sorry because I'm not a mathematician so that my question may look a little bit messy. I have tabulated values [1] of a 3 dimensional radial function $f(r)$: ...
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1answer
170 views

Closed-form solution for this system of ODEs

I am trying to solve the following system (derived from a Michaelis-Menten kinetics model for an enzymatic chemical reaction): $$\dot{y}_a = r_p x_a - \lambda_p y_a$$ $$\dot{x}_b = \frac{\alpha_0 + ...
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2answers
2k views

(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 ...
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4answers
196 views

Trying to balance equation

I tried balancing this chemical equation with a system of equations, but the answer doesn't seem to map well. I get a negative coefficient which is prohibitive in this equations. How do I interpret ...
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1answer
542 views

Chemistry: Gravimetric determination of copper in ore

Hey, sorry for the non so mathematical question but that's the only place where I'd thought someone would answer this so here we go. I'm doing a chemistry homework and I have to answer this very ...
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2answers
349 views

Asimov quote about “eight million trillion” arrangements of amino acids

A friend of mine is subediting a book. The author of the book 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 ...
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4answers
3k views

Balance chemical equations without trial and error?

In my AP chem class, I often have to balance chemical equations like the following: $$ \text{Al} + \text O_2 \to \text{Al}_2 \text O_3 $$ The goal is to make both side of the arrow have the same ...