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]

200 questions

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### Linear Algebra Problem (Chemistry)

$$C_2H_2 + O_2\rightarrow H_2O + CO_2$$
How do I solve this equation problem with linear algebra? How do I take vectors and matrix so what should I do at here? But the answer is: $$2C_2H_6 + 7O_2\rightarrow 6H_2O + 4CO_2$$
Would someone show me…

user444479

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### Is pH found using negative log because the scientific notation of the number of hydrogen atoms in a solution is always negative?

I understand subtraction negates addition, and since log and exponents are basically addition and subtraction on steroids, then log must be the way to negate exponents. So from this rationale, is it fair to say that log is negative because the…

55 Cancri

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### Easy and reliable method for solving four nonlinear equations

I have the following four equations with their four variables:
$$4.5*10^{-4}x=yz$$
$$z=\frac{10^{-14}}{t}$$
$$y=0.02-x$$
$$z=t+y$$
I'm going to be solving a lot of equations in a similar manner (with similar structures) so I would like a reliable…

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### Adding pure solution to a mixture, what is the resulting concentration?

The antifreeze in my car is a mixture of pure antifreeze and water; the concentration of antifreeze is $50 \%$. Today, I added some pure antifreeze (the volume of liquid I added is about $\dfrac 14$ the volume of the liquid that was already…

Ovi

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### Determining the number of isomers of alkanes using trees and adjacency tables

I've been looking for a formula determining the number of possible isomers for a given organic compound. As such formula does not exist I though I could do a little investigation on my own. I looked at alkanes:
Structural formulas of alkanes may be…

Daphne

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### 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 think it's a sine function. Like sin(10x) or…

Gᴇᴏᴍᴇᴛᴇʀ

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### How to solve a differential system using Runge-Kutta 2nd order method?

I have question to solve using RK2. Your help is highly appreciated.
In a reversible chemical reaction concentrations $A$ and $B$ given in $\rm \text{g-mol}/L$ of two compound, change at rates given by
$$
\begin{align}
\frac{dA}{dt} &= -k_1 A^2 +…

chanuwick

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### Solving for numerator in equation with logarithms (Activation Energy Equation)

I'm having trouble solving for k1 in this equation:
ln(0.286/k1) = (100000/8.314)(1/500 - 1/490)
The right side should equal 0.491, which I can calculate just fine, but then the left side gives me trouble. Here's my approach:
ln(0.286/k1) = 0.491…

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### Cannot solve this integral used in quantum chemistry

I am writing computer code for an implementation of the Hartree Fock algorithm and I am stuck on a certain integral. This is a great walkthrough to get some background : HFTheory
Anyway, the set-up is this. I am using a single Guassian type orbital…

user2879934

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### ODE Oscillation, overdampening response

Below is another version of the creme brulee model. $k_{11}, k_{12},k_{21},k_{22}$ and $A$ are all positive constants. Show the the solutions to these ODEs can never oscillate (proof for $T_1$ is sufficient). In other words, the temperature of the…

klorzan

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### Normalizing data to new percentage total?

I have a range of percentage compositions for chemicals in dry air. At the moment they all total to 100%. For example chemical a=35%, b=20%, c=20%, d=10% and e=15%. If I were to alter the percentage composition of chemical e to 18%, how would I…

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### Uncertainty powers

In class, we are working with powers of uncertainties. The teacher, however, handed me an extremely technical article, and it makes very little sense. Could one please explain to me step by step how to solve this…

user266519

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### relating mole fraction to molality

If the mole fraction of water in a HCl solution is 0.78 . calculate the molality of the solution?
I don't understand how to relate mole fraction to molality.

tapadia newlon

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### How do I integrate the differential equation?

I have an equation from chemistry:
$$\frac{\delta (\frac{\Delta G}{T})}{\delta T}=-\frac{\Delta H}{T^2}$$
This is known as the Gibbs-Helmholtz equation.
Now according to Wikipedia, if I integrate this, I would get:
$$\frac{\Delta…

noob anomaly

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### Wolfram Alpha is doing something I don't understand, please help

I am using Newton Raphson method to obtain the velocity of a chemical reaction, and I needed to derive the next equation:$$\frac{d}{dk}\left(\left(\frac{0.35}{k}\right)^{\frac{k}{k-0.35}}\right)= -0.3285178\left(\frac{1}{k}\right)^{1.65}$$ And the…

Bopemagno

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