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)

Science

chemical equation is the symbolic representation of a chemical reaction in the form of symbols and formulae, wherein the reactant entities are given on the left-hand side and the product entities on the right-hand side with a plus sign between the entities in both the reactants and the products and an arrow that points towards the products, and shows the direction of the reaction.[1] The coefficients next to the symbols and formulae of entities are the absolute values of the stoichiometric numbers. The first chemical equation was diagrammed by Jean Beguin in 1615.[2] 49.156.66.160 (talk) 17:39, 27 May 2022 (UTC)

Unfortunately it's unclear what your intention is. If you are recommending changes to the original page, where shoud they be? And what are the actual citations that you're pointing out? Qflib, aka KeeYou Flib (talk) 01:57, 30 June 2022 (UTC)

It is just a verbatim copy from the lead section. I suggest deleting it as an editing experiment. Petr Matas 02:08, 30 June 2022 (UTC)

Explicit single bonds

In the example equation for dehydration of methanol to dimethylether I am using a dash to explicitly show the single bonds between carbon and oxygen:

${\ce {2 CH3-OH -> CH3-O-CH3 + H2O}}$

It is an attempt to make the functional groups, which are directly involved in the reaction, easier to spot, given that this article introduces some of the most basic reaction equations. It seems however, that this formula style is not very common, so doubts about my decision have come to my mind. Should the dashes be removed to get ${\ce {2 CH3OH -> CH3OCH3 + H2O}}$ ? Petr Matas 23:10, 29 June 2022 (UTC)

Explicit dashes are not used in chemical equations unless the intent is to specifically highlight changes in bond order caused by the reaction. Qflib, aka KeeYou Flib (talk) 01:55, 30 June 2022 (UTC)

Notation variants

The section entitled "Notation variants" introduces notation that I have never seen before, and does so without using any citations to reliable sources. t seems to me that the entire section should be removed unless some reliable citations are introduced. Qflib, aka KeeYou Flib (talk) 02:01, 30 June 2022 (UTC)

I believe that at least the first two variants are well established and someone will surely be able to find reliable sources. For example here at Wikipedia we have the article Hydrolysis with this figure. What I don't know is whether such figure can be said to consist of chemical equations. You may be right about the last variant (product on the left-hand side). However many high-school chemistry students tend to use it as an analogy to math equations, even though it may be considered incorrect (see the ref to Stack Exchange). That is why I believe it is worth noting and it should be possible to find something about it somewhere. ;-) Petr Matas 02:43, 30 June 2022 (UTC)