Talk:Chemical equation

State of matter Marking

Do not use subtext to mark the state of matter of a material in the equation.
NaCl(aq)+AgNO3(aq)→AgCl(s)+NaNO3(aq) $\surd \!$
NaCl_(aq)+AgNO_3(aq)→AgCl_(s)+NaNO_3(aq)$X\!$
--Derg(hu.wikipedia.org)--81.182.49.127 (talk) 10:40, 4 January 2009 (UTC)

Overhaul of article

I'm going to try and overhaul this article to be clearer, as well as expand what is presented. I've already started deleting the how-to information presented. I plan on providing some graphics to explain the parts of a chemical equation among other plans. Chemeditor (talk) 23:28, 6 October 2008 (UTC)

Merger with Ionic/Molecular Equation

I propose merging Ionic equation into a subsection of the chemical equation article because ionic equations really are just a subset of the more general idea of chemical equations. Considering the limited information presented in both articles, it would be best to combine them. Chemeditor (talk) 22:54, 5 October 2008 (UTC)

I also suggest adding Molecular equation into the main article for the reasons above. Chemeditor (talk) 23:03, 5 October 2008 (UTC)

I've gone ahead and merged the two other articles into this one. Chemeditor (talk) 02:33, 10 October 2008 (UTC)

Linear systems balancing

But I ask someone to add some better method for equation balancing since what is there although is kinda practical reasoning, it's not so suitable for complex cases and also takes a lot of text to explain(someone should clean that up too). But what I really want is to suggest a description of linear systems balancing, which I find much more effective and elegant. I will give an example:

K₄Fe(CN)₆ + H₂SO₄ + H₂O → K₂SO₄ + FeSO₄ + (NH₄)₂SO₄ + CO

The method consists in the following:

1. Assign variables to each coefficient:

a K₄Fe(CN)₆ + b H₂SO₄ + c H₂O → d K₂SO₄ + e FeSO₄ + f (NH₄)₂SO₄ + g CO

2. We must have the same quantities of each atom in each side of the equation. So, for each element, count its atoms and equal both sides:

K: 4a = 2d

Fe: 1a = 1e

C: 6a = g

N: 6a = 2f

H: 2b+2c = 8f

O: 4b+c = 4d+4e+4f+g

3.

d=2a

e=a

g=6a

f=3a

b=6a

c=6a

which means that we have all coefficients depending on a parameter a, just choose a=1(a number that will make all of them small whole numbers) and you'll have:

a=1 b=6 c=6 d=2 e=1 f=3 g=6

4. And the balanced equation at last:

K₄Fe(CN)₆ + 6 H₂SO₄ + 6 H₂O → 2 K₂SO₄ + FeSO₄ + 3 (NH₄)₂SO₄ + 6 CO

One could argue that this method requires much more work than the other, for that reason I will show that combining both can lead to a very efficient and quick way of balancing(although for very complex cases I would keep this one in the pocket):

1. Identify elements which occur in one compound in each member(this is very usual)

2. Start with the one among those which has a big index(this will help to keep working with integers), and assign a variable, let's say a.

a K₄Fe(CN)₆ + H₂SO₄ + H₂O → K₂SO₄ + FeSO₄ + (NH₄)₂SO₄ + CO

3. Well, K₂SO₄ has to be 2a(because of K), and also, FeSO₄ has to be 1a(because of Fe), CO has to be 6a(because of C) and (NH₄)₂SO₄ has to be 3a(because of N). Well, this takes out the first four equations of the system! We already now that, whatever the coefficients are, those proportions must hold:

a K₄Fe(CN)₆ + H₂SO₄ + H₂O → 2a K₂SO₄ + a FeSO₄ + 3a (NH₄)₂SO₄ + 6a CO

4. We can continue by writing the equations now(and having simpler problem to solve) or, in this particular case(although not so particular) we could continue by noticing that adding the Sulfurs we get 6a for H₂SO₄ and finally by adding the hydrogens(or the oxygens) we get the lasting 6a for H₂SO₄.

5. Again, having a convienient value for a(in this case 1 will do, but if a gets fractionary values in the other coefficients you will like to cancel the denominators) we get the result:

K₄Fe(CN)₆ + 6 H₂SO₄ + 6 H₂O → 2 K₂SO₄ + FeSO₄ + 3 (NH₄)₂SO₄ + 6 CO

Rend 03:06, 10 August 2005 (UTC)

I added it as I described it here, I think it need to be better written although. Rend 04:21, 19 December 2005 (UTC)

I don't know if this helps anyone but I thought I would mention that the reverse arrows display as boxes in MSN Explorer 9.2 64.114.88.154 23:14, 30 March 2006 (UTC)

I thinik this method for balancing chemical equation is very appropriaye and suitable .Teacher should Be encouraged to use this method to teach teach their student even this method should be added in the cource.I unterstood ths method for chemical equation. — Preceding unsigned comment added by Rahul Prasad wagle (talk • contribs) 02:27, 1 April 2016‎ (UTC)

Wikipedia is not a how-to

I'm concerned about this article because it reads like a how-to guide and Wikipedia directives explicitly state that Wikipedia is not supposed to be a how-to guide. Perhaps we can clean this up? -SocratesJedi | Talk 03:48, 28 January 2007 (UTC)

I agree this article reads mostly as a how-to; particularly the Balancing Equations section. I recommend keeping Ex. 1 from the Balancing Chemical Equations section and moving the rest of the section into a WikiHow or WikiBooks article. That would get across the important point, namely matter cannot be created or destroyed during a chemical reaction. The rest of the examples serve only to describe how to balance an equation; they provide no new information about chemical equations. Chemeditor (talk) 19:02, 5 October 2008 (UTC)

Merge with Chemical Formulas

They seem to share the same scope. Maybe we should merge them? P3net 00:14, 7 March 2007 (UTC)

I do not think this would be appropriate. A chemical formula does not imply an equation. For example, NaCl is an example of a formula, but is not an equation. On the other hand, Na + Cl --> NaCl is an equation that contains formulas. Chemeditor (talk) 19:07, 5 October 2008 (UTC)

chemical equations

maybe you can add the identifications of the different symbols used in solving chemical equations? that will be a big help... thanks —Preceding unsigned comment added by 124.107.87.250 (talk) 02:48, 25 November 2007 (UTC)

State Symbols

The article doesn't explain what the state symbols mean, it just jumps into using them. The symbols I'm talking about are: (aq),(I),(S), ... etc... Like: AgCl(s) I remember that (aq) means aqueous, but its been a while since I took chemistry and don't remember the others.75.82.133.73 (talk) 12:28, 18 October 2008 (UTC)

External links

Are any of them viable per WP:EL? Looks to me like just a bunch of random "yet another" teaching/practice-problems or reaction-balancing applets. Might be a good pile for DMOZ, but not here IMO. DMacks (talk) 21:50, 2 February 2009 (UTC)

Chemical states missing

In the net ionic queation example, the precipitates is marked as solid (s), but the ions aren't marked as aqueous (aq). As my current chemistry proffesor keeps reminding me, a chemical equation must have all chemical states labeled "or it's wrong." I'm not sure if that is his opinion on the matter (no pun intended), or if he's trying to teach the scientific standard. Could an expert check this? NickNackGus (talk) 23:08, 8 October 2012 (UTC)

I cannot find that requirement in anything authoritative, such as IUPAC rules. But your textbook might include it as a best practice or in the context of learning about the nature of the chemical changes (up through intro-college level), and therefore your professor might require it when grading assignments on those topics. It is an explicit indication of more of the changes that is occurring (not just the ions combining and becoming a solid result, but also that they become desolvated). "The physical state of chemicals is also very commonly stated in parentheses after the chemical symbol, especially for ionic reactions" (emphasis mine). I added a comparative example to the article. DMacks (talk) 14:12, 10 October 2020 (UTC)