Chemical Equation Balance
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Hello. I am still learning C# and as a new project, I wanted to write a simple chemical equation balancer, but dont really know where to start. I am not asking for code, as I really want to have a go at this myself, so if I show my views below on how I would imagine tackling this problem, maybe someone could point me in the correct direction. An example of a chemical equation, a simple one, would be... H2 + O2 = H2O Balanced, we end up with..... 2H2 + O2 = 2H2O I was thinking of the following steps... 1) Parse the left side (reactants) into one string, and the right side (Products) into a seperate string. 2) Loop through the string looking for the letters representing the elements and the numbers to count how many we have 3) ** Havent got a clue how to manage this ** maybe use some kind of matriz to store all the values and then use logic to "balance" the equation. Does anyone have any ideas or tips? Thank you, Regards, Steve
Just my tuppenceworth, the other answers have been good. There is a full balancing method here[^]. It should transfer to an algorithm easily. For the data representation I'd use two dictionaries, one for the number atoms on the LHS, the other for the right. You can make the chemical symbol the key, but you might also like an element class, that way you can do other handy stuff like work out the molar mass of the products etc. I actually think the formula parser might be the hard part, but not having worked on the problem fully I could well be wrong.
Sort of a cross between Lawrence of Arabia and Dilbert.[^]
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A Dead ringer for Kate Winslett[^] -
Hello. I am still learning C# and as a new project, I wanted to write a simple chemical equation balancer, but dont really know where to start. I am not asking for code, as I really want to have a go at this myself, so if I show my views below on how I would imagine tackling this problem, maybe someone could point me in the correct direction. An example of a chemical equation, a simple one, would be... H2 + O2 = H2O Balanced, we end up with..... 2H2 + O2 = 2H2O I was thinking of the following steps... 1) Parse the left side (reactants) into one string, and the right side (Products) into a seperate string. 2) Loop through the string looking for the letters representing the elements and the numbers to count how many we have 3) ** Havent got a clue how to manage this ** maybe use some kind of matriz to store all the values and then use logic to "balance" the equation. Does anyone have any ideas or tips? Thank you, Regards, Steve
No trial and error or inelegant algorithms are needed. The problem can be solved by solving a system of linear equations, constructed like this: As2S3 + HNO3 + H2O = H3AsO4 + H2SO4 + NO (unbalanced) Should be turned into the system: (disclaimer: it was really quite late when I did this, so don't look at the numbers too closely the general principle should be sound though)
2 x0 + 0 x1 + 0 x2 - 1 x3 - 0 x4 - 0 x5 = 0 // for As
3 x0 + 0 x1 + 0 x2 - 0 x3 - 1 x4 - 0 x5 = 0 // for S
0 x0 + 1 x1 + 2 x2 - 3 x3 - 1 x4 - 0 x5 = 0 // for H
0 x0 + 1 x1 + 0 x2 - 0 x3 - 0 x4 - 1 x5 = 0 // for N
0 x0 + 3 x1 + 1 x2 - 4 x3 - 4 x4 - 1 x5 = 0 // for OThe variables correspond to how many times the molecule from the unbalanced equation is needed, the coefficients correspond to how many of the element are in the corresponding molecule. If I did the math correctly, it gives: 3 As2S3 + 28 HNO3 + 4 H2O = 6 H3AsO4 + 9 H2SO4 + 28 NO Does that help you any?
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No trial and error or inelegant algorithms are needed. The problem can be solved by solving a system of linear equations, constructed like this: As2S3 + HNO3 + H2O = H3AsO4 + H2SO4 + NO (unbalanced) Should be turned into the system: (disclaimer: it was really quite late when I did this, so don't look at the numbers too closely the general principle should be sound though)
2 x0 + 0 x1 + 0 x2 - 1 x3 - 0 x4 - 0 x5 = 0 // for As
3 x0 + 0 x1 + 0 x2 - 0 x3 - 1 x4 - 0 x5 = 0 // for S
0 x0 + 1 x1 + 2 x2 - 3 x3 - 1 x4 - 0 x5 = 0 // for H
0 x0 + 1 x1 + 0 x2 - 0 x3 - 0 x4 - 1 x5 = 0 // for N
0 x0 + 3 x1 + 1 x2 - 4 x3 - 4 x4 - 1 x5 = 0 // for OThe variables correspond to how many times the molecule from the unbalanced equation is needed, the coefficients correspond to how many of the element are in the corresponding molecule. If I did the math correctly, it gives: 3 As2S3 + 28 HNO3 + 4 H2O = 6 H3AsO4 + 9 H2SO4 + 28 NO Does that help you any?
yep, linear equations it is; each different element gives one equation, and the unknowns are the amounts of each of the molecules. the one funny thing is there could be more equations than unknowns, making either some of them redundant, or the problem unsolvable (obviously you can't balance H2O = H2SO4 ). :)
Luc Pattyn [My Articles] Nil Volentibus Arduum
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yep, linear equations it is; each different element gives one equation, and the unknowns are the amounts of each of the molecules. the one funny thing is there could be more equations than unknowns, making either some of them redundant, or the problem unsolvable (obviously you can't balance H2O = H2SO4 ). :)
Luc Pattyn [My Articles] Nil Volentibus Arduum
Luc Pattyn wrote:
yep, linear equations it is
Geez, man. Is there anything you don't know? :)
The difficult we do right away... ...the impossible takes slightly longer.
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Luc Pattyn wrote:
yep, linear equations it is
Geez, man. Is there anything you don't know? :)
The difficult we do right away... ...the impossible takes slightly longer.
I only know a tiny fraction of all there is to know, however I try and make up for it by applying simple logic. :-D And chemical formulae are all about preserving the elements...
Luc Pattyn [My Articles] Nil Volentibus Arduum
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Hello. I am still learning C# and as a new project, I wanted to write a simple chemical equation balancer, but dont really know where to start. I am not asking for code, as I really want to have a go at this myself, so if I show my views below on how I would imagine tackling this problem, maybe someone could point me in the correct direction. An example of a chemical equation, a simple one, would be... H2 + O2 = H2O Balanced, we end up with..... 2H2 + O2 = 2H2O I was thinking of the following steps... 1) Parse the left side (reactants) into one string, and the right side (Products) into a seperate string. 2) Loop through the string looking for the letters representing the elements and the numbers to count how many we have 3) ** Havent got a clue how to manage this ** maybe use some kind of matriz to store all the values and then use logic to "balance" the equation. Does anyone have any ideas or tips? Thank you, Regards, Steve
As others have noted, the problem can be re-stated in terms of a system of linear equations. A particularly easy method to solve such systems (in relative terms, of course - it's a decent homework assignment for a second-year CS student) is the method of Gaussian Elimination[^]. Here is a Java implementation of what you are trying to build[^], conveniently packaged with a source code. The implementation is very easy to follow, even if you do not know Java (but do know some C#). Good luck!
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Hi, Thank you, this was pretty much what I was thinking. Do you have any ideas of the best way to store and sort the terms? i.e. Should I use a struct for the elements? etc I am still a beginner so any advice is most welcomed. Kind Regards, Stephen
I would probably set this up as two arrays, operands (left side) and results (right side). The arrays would contain structures that have two elements. The first element would be the multiplier for the particular item, and a dictionary with the element symbol as the key and the how much as the value. The Dictionary object has a sort method built in, but you'll probably want to write your own to meet the requirements for sorting the particular elements according the the standard rules of chemistry. For example S comes before O for SO4. I hope you find this approach helpful. If you have any questions, feel free to ask.
Scott E. Corbett Software Engineer/Analyst
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No trial and error or inelegant algorithms are needed. The problem can be solved by solving a system of linear equations, constructed like this: As2S3 + HNO3 + H2O = H3AsO4 + H2SO4 + NO (unbalanced) Should be turned into the system: (disclaimer: it was really quite late when I did this, so don't look at the numbers too closely the general principle should be sound though)
2 x0 + 0 x1 + 0 x2 - 1 x3 - 0 x4 - 0 x5 = 0 // for As
3 x0 + 0 x1 + 0 x2 - 0 x3 - 1 x4 - 0 x5 = 0 // for S
0 x0 + 1 x1 + 2 x2 - 3 x3 - 1 x4 - 0 x5 = 0 // for H
0 x0 + 1 x1 + 0 x2 - 0 x3 - 0 x4 - 1 x5 = 0 // for N
0 x0 + 3 x1 + 1 x2 - 4 x3 - 4 x4 - 1 x5 = 0 // for OThe variables correspond to how many times the molecule from the unbalanced equation is needed, the coefficients correspond to how many of the element are in the corresponding molecule. If I did the math correctly, it gives: 3 As2S3 + 28 HNO3 + 4 H2O = 6 H3AsO4 + 9 H2SO4 + 28 NO Does that help you any?
Dear David1987, Sorry, no, it does not help at all unfortunatly. I can't seem to work out what is going on here, although I suspect if I did it may prove a usefull way of approaching the problem. Is there any chance you could show me what you mean, or maybe simplyfy it a little? Thank you
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As others have noted, the problem can be re-stated in terms of a system of linear equations. A particularly easy method to solve such systems (in relative terms, of course - it's a decent homework assignment for a second-year CS student) is the method of Gaussian Elimination[^]. Here is a Java implementation of what you are trying to build[^], conveniently packaged with a source code. The implementation is very easy to follow, even if you do not know Java (but do know some C#). Good luck!
Thank you everyone for your help. However, I think as a complete beginner, I may have bitten off more than I can chew, as I dont have a clue where to start based on the information provided. Thank you again, Stephen
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Dear David1987, Sorry, no, it does not help at all unfortunatly. I can't seem to work out what is going on here, although I suspect if I did it may prove a usefull way of approaching the problem. Is there any chance you could show me what you mean, or maybe simplyfy it a little? Thank you
Ok, let's take O2 + H2 = H2O then. First I'll assign variables to the molecules: O2 = x0 H2 = x1 H2O = x2 Then I build the equations, one for each element, the coefficients are how much of the current element is in the corresponding molecule: H: 0 x0 + 2 x1 - 2 x2 = 0 // there is zero H in O2, 2 H in H2, 2 H in H2O O: 2 x0 + 0 x1 - 1 x2 = 0 // there is 2 O in O2, zero O in H2, 1 O in H2O The smallest solution where all variables are integers is x0 = 1, x1 = 2, x2 = 2, which corresponds to O2 + 2 H2 = 2 H2O
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Hello. I am still learning C# and as a new project, I wanted to write a simple chemical equation balancer, but dont really know where to start. I am not asking for code, as I really want to have a go at this myself, so if I show my views below on how I would imagine tackling this problem, maybe someone could point me in the correct direction. An example of a chemical equation, a simple one, would be... H2 + O2 = H2O Balanced, we end up with..... 2H2 + O2 = 2H2O I was thinking of the following steps... 1) Parse the left side (reactants) into one string, and the right side (Products) into a seperate string. 2) Loop through the string looking for the letters representing the elements and the numbers to count how many we have 3) ** Havent got a clue how to manage this ** maybe use some kind of matriz to store all the values and then use logic to "balance" the equation. Does anyone have any ideas or tips? Thank you, Regards, Steve
If college chemistry can offer me anything it was that no equation balancer should be based on text input. The one I had to use was so bad I dared the prof. to fail me because I wasn't going to waste my time discovering how it wanted me to type. Graphics and numeric up downs in a visually appealing manner are the way to go.
Need custom software developed? I do custom programming based primarily on MS tools with an emphasis on C# development and consulting. I also do Android Programming as I find it a refreshing break from the MS. "And they, since they Were not the one dead, turned to their affairs" -- Robert Frost
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Ok, let's take O2 + H2 = H2O then. First I'll assign variables to the molecules: O2 = x0 H2 = x1 H2O = x2 Then I build the equations, one for each element, the coefficients are how much of the current element is in the corresponding molecule: H: 0 x0 + 2 x1 - 2 x2 = 0 // there is zero H in O2, 2 H in H2, 2 H in H2O O: 2 x0 + 0 x1 - 1 x2 = 0 // there is 2 O in O2, zero O in H2, 1 O in H2O The smallest solution where all variables are integers is x0 = 1, x1 = 2, x2 = 2, which corresponds to O2 + 2 H2 = 2 H2O
Hi, OK that helps a little better, but I would have no idea how to implement this into code. It has gave me something to think about though. Thank you again, Stephen
