# Differential equations and chemistry

#### Will

[SOLVED] Differential equations and chemistry

Would someone be so kind as to cook me up a sample problem relating DFQ's to chemistry? Maybe a reaction rate type problem? I do know that the rate of change in say, a 2nd order reaction is proportional to the concentration squared, but I don't know exactly how to set it up.
This is for my own interest only, nothing assigned from school. In fact, I want to learn this because even my Chem prof. didn't know exactly how to do it, and there isn't much in chem. that this guy doesnt know. I have just completed my first course in DFQ's, and its application really interests me. Would I be able to understand this type of problem? I only know how to do at most homogenous and non-homogenous 2nd order equations(and also systems of equations), and we started to do Laplace Transforms at the end of the course. I think we skipped some of the more sophisticated stuff.
If someone could come up with something, this would be greatly appreciated.

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#### Turtle

I don't think, that differential equations apply to chemistry.

#### Tom Mattson

Staff Emeritus
Gold Member
Originally posted by Will
Maybe a reaction rate type problem? I do know that the rate of change in say, a 2nd order reaction is proportional to the concentration squared, but I don't know exactly how to set it up.
That's pretty straightforward. Check this out:

http://scienceworld.wolfram.com/chemistry/RateLaw.html

This is for my own interest only, nothing assigned from school. In fact, I want to learn this because even my Chem prof. didn't know exactly how to do it, and there isn't much in chem. that this guy doesnt know.
That sounds pretty strange, as the stuff in the website above (at least 1st and 2nd order rate laws) is in every general chemistry book.

#### rutwig

Originally posted by Turtle
I don't think, that differential equations apply to chemistry.
Oh, no. All equilibrium problems are indeed differential equations, even if normally chemistry books don't say it explicitely. Indeed almost any process (physical or chemical) involving changes is rules by equations of this type. Look for example at thermodynamical problems.

#### Will

Re: Re: Differential equations and chemistry

Originally posted by Tom

That sounds pretty strange, as the stuff in the website above (at least 1st and 2nd order rate laws) is in every general chemistry book.
Thats because calculus is not a pre-req for general chem, so its not explicitly stated. The website cleared that up, that is exactly the info I wanted. It was simpler than I thought, all just separable 1st order eq.
So what about 2nd order equations, are they any related to chemistry,? Or how about linear first order eq? We did some like that in mixing problems already, but all problems assumed that the solute instantaneously mixed into solution.

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