Talk:Chemical reaction

message: This text was removed, as it does not belong in the main text, but rather in Talk about this topic:
 
:Note: a enumeration of the types of chemical reactions is neededEdited by D.C.
We're going to have problems with some editors, because it seems they have no practical experience with what real chemists, in real usage, call a chemical synthesis. This corruption of use, which started in the chemical synthesis article, seems to be migrating to this article as well, and it will be stopped :). The next point is that this article should not be ended with a brainless enumeration of kinds of chemical reactions, but it could be well served by a series of links to Wikipedia articles on types of chemical reactions, articles which already exist within the Wikipedia. For example there already are articles on hydrolysis and one on the hydration reaction. Other articles on chemical reactions are embedded in the article on the compound itself (e.g. soap and saponification). Dwmyers 23:05, 10 Nov 2003 (UTC)
thread_title: Distinguish "synthesis" from "reaction" and avoid list of reactions

message: *Chemical reaction - This page needs a lot of work by someone with more chemistry knowledge than I have. The energetics of reactions need to be cleared up, and links made to pages like reaction coordinates, transition states, reactive intermediate, and such. There is a list of the "6 types of reactions", which other people have added to, with reactions that don't seem to fit into those six categories. The reaction rate section is almost nonexistent, the "Law of mass action" section is just one line (how about some history, or a more detailed explanation?). Finally, the "See also" list needs serious expansion.
:This page could become a central point for articles dealing with chemical reactions, but as it stands, it is orphaned from a lot of them, and quite incomplete. --Kieran 12:04, 11 Apr 2005 (UTC)
thread_title: From PNA/Chemistry

message: This article was not written by a person with much knowledge about chemical reactions. Chemist is needed to rewright it. stone 6 Apr 2005
*It's a tough job, even for a chemist! Physchim62 21:25, 15 Jun 2005 (UTC)
thread_title: More

message: Is this correct? Where do the additional reactions that have been added under this section fit in? I would like to fix that section, so the entries at the bottom of the list look like the rest of them, but I'm holding back because of the "six types" statement. --Kieran 11:10, 11 Apr 2005 (UTC)
thread_title: Six types of chemical reaction?

message: The trouble with this stuff is that it's hard to aim it at the right level -as a degree chemist it's fairly hard to think back to when I didn't know anything about chemical reactions. Maybe I should borrow some chem textbooks for 13-year olds and see what they write?
Also why does 'compound' not occur in the introduction? argh! It really needs a full rewrite of the intro but not really sure what.
Excession 5 July 2005 08:23 (UTC)
:I don't think we should be aiming at a 13-year old level: in France, the reaction formalism is introduced at about age 16 (class of Seconde), although we talk about chemical transformations before then. Thanks to all those who are trying to do something with this article, it seems beyond me to improve it for the moment however much it needs it! Physchim62 5 July 2005 08:41 (UTC)
===13-year-old is a good level anywhere===
Why can't we aim at a 13-year-old level? It would be valuable, for example, in the discussion of thermodynamics, to state simply how combustion creates heat. Where does heat come from? Just saying that there is a reduction of mass is not an explanation. We cannot assume that our readers have the same level of understanding or literacy as we do. The simpler the language, the bigger the audience. Bdubay (talk) 04:36, 24 July 2012 (UTC)
replies: text: Why 13 and not 10 yo or 19 yo? Maybe http://simple.wikipedia.org/wiki/Chemical_reaction is a better venue for simplified articles. Materialscientist (talk) 04:58, 24 July 2012 (UTC)
thread_title:  Level we're aiming at 

message: Why can't we aim at a 13-year-old level? It would be valuable, for example, in the discussion of thermodynamics, to state simply how combustion creates heat. Where does heat come from? Just saying that there is a reduction of mass is not an explanation. We cannot assume that our readers have the same level of understanding or literacy as we do. The simpler the language, the bigger the audience. Bdubay (talk) 04:36, 24 July 2012 (UTC)
replies: text: Why 13 and not 10 yo or 19 yo? Maybe http://simple.wikipedia.org/wiki/Chemical_reaction is a better venue for simplified articles. Materialscientist (talk) 04:58, 24 July 2012 (UTC)
thread_title: 13-year-old is a good level anywhere

message: consider the reaction H + H -> H2 + Q
E = mc^2 is independent of the form of matter. and the energy contained on both sides of chemical reaction formula is equal. so is it right to assume the mass of H2 is slightly less than 2 H atoms?
:Yes, indeed! Any transformation that involves a change in energy also involves a change in mass.--Nevermore78 01:20, 3 April 2006 (UTC)
thread_title:  E = mc^2 and chemical energy?

message: The phasing of the concept of an irreversible reaction seems oddly stif.
:"This phrase means that nearly all of the reactants are used to form products. These reactions are very difficult to reverse even under extreme conditions."
'Used'? Would 'expended' fit better?
And could we perhaps add an example of such a reaction? Combustion of methane or hydrogen seem to be less than ideal examples, but surely we can find an informative example. -- Ec5618 18:34, 1 February 2006 (UTC)
thread_title: Chemical equilibrium

message: ::C10H8 (g) + 12O2 (g) → 10CO2 (g) + 4H2O (l)
Does not combustion normally produce water vapour (gas, not a liquid)? Shouldn't the last element be 4H2O (g)? - Mike Rosoft 14:34, 10 April 2006 (UTC)
replies: text: If you are using the equation to describe the process of measuring the heat of combustion at a temperature of 25C, then you give the reactants and products in their natural state at that temperature. Think of it starting at 25C, it burns and then everything cools back to 25C. The water condenses. The equation is correct. --Bduke 21:49, 10 April 2006 (UTC)
replies: text: It's "correct", sort of, but describes a different process. This process doesn't involve only a chemical reaction, but also a heat transfer after the reaction has taken place. So, it's two processes bundled up for no good reason. --Vuo 01:13, 11 April 2006 (UTC)
replies: text: It is not normal to put "+ heat" in a chemical equation. That is out of date useage. You might add the heat or rather enthalpy of reaction after the equation (ΔH = xx kJ/mol). It is clear that heat is given out because it is a combustion reaction. Your last edit is wrong. The states should be all at standard temperature or specifically 25C. What we want here is an exact correct balanced chemical equation. I'm going to leave it for now and see what others think. --Bduke 02:27, 11 April 2006 (UTC)
replies: text: In fact, in that section, the phases are irrelevant. --Vuo 20:30, 15 April 2006 (UTC)
thread_title: Example combustion reaction

message: As much of this article, the thermochemistry discussion here is unecessarly confusing and ambiguous. Why to discuss kinetics with two whole paragraphs on thermochemistry's lead? Or why presenting the general criteria of spontaniety (Gibbs Free Energy/Global Entropy) almost as an exception? Applying high school assumptions here won't make the topic that much amiable. I am thinking on a way of rephrasing things on that section, but I have not quite a solid formulation ATM. In the meantime, I invite fellow editos to clarify things - particularly if one knows some Physical Chemistry...--Duplode 05:26, 14 April 2006 (UTC)
thread_title:  Thermodynamics section 

message: is a phase change 9i.e. evaporation or condensation) a chemical reaction?  --Crucible Guardian 03:46, 6 July 2006 (UTC)
replies: text: No, it's usually considered to be just a physical process in simple cases like water boiling or freezing.  There are many cases where it could be considered as a chemical reaction - for example, solid sulfur is mainly S8, sulfur vapor is S2, so clearly some covalent bonds are broken in going from solid to vapor. Walkerma 07:01, 6 July 2006 (UTC)
thread_title:  Phase Change 

message: Shoudn't there be a link to this page that allready links here ? samusz 12:22, 4 September 2006 (UTC)
thread_title:  By-product 

message: someone needs to reword the first sentence of this subheading, someone's idea of a sick joke.72.137.252.165 23:06, 5 September 2006 (UTC)
thread_title:  reaction types 

message: I think we should edit the example equations to include state functions (g, aq, l, s) to help with understanding.71.111.98.144 03:26, 21 November 2006 (UTC)
thread_title:  State Functions 

message: I tried to correct the current vandalism but couldn't see the original sentence (that was changed) at the beginning of the article. Also, looking back at previous revisions, there has been a fair amount of vandalism in the past. Aboyall 19:58, 24 January 2007 (UTC)
thread_title: Repeated vandalism

message: I reverted the recent change, back to "thermodynamically favored."  This is a standard term in chemistry, and it gets over 83,000 hits in Google.  By contrast, "favored in a thermodynamical way" gets no hits. Walkerma 05:27, 30 April 2007 (UTC)
thread_title:  "Thermodynamically favored" 

message: It seems this particular article, by the pursue of simplicity in explanation and sharpness in classification, always has its focus, breadth and accuracy at stake. I have attempted to clarify some wordings and, more importantly, performed a number of deletions, which I put up for discussion:
On the classical definition, therefore, there are only two types of chemical reaction: redox reactions and acid-base reactions. The former involve the motion of lone electrons and the latter of an electron pair.
Overtly restrictive. Think of cis-trans isometization: one might argue the reaction can be mechanistically be described in terms of homo/heterolytic bond cleavage/forming, but it is doubtful whether saying the reaction as a whole is redox or acid-base is relevant or even viable. Or even better, think of pericyclic reactions.
Chemical reactions are also divided into organic reactions and inorganic reactions.
So people really think classification is important enough to go on the lead. Not to mention organometalic chemistry.
The collision of more than two particles into the ordered structure necessary to perform chemical transformations is extremely unlikely; which is why ternary reactions in practice are not observed. A chemical reaction may require three or more reagents, but the process can generally be decomposed into a stepwise series or a set of stepwise reactions of the above.
Although I have not removed this, it feels completely misplaced under the "Reaction Types" heading. And if "the above" refered to the list of types two paragraphs before, it was plain catastrophic constraining -hence, the rewording.
     * Petrochemical reactions are often distinguished from other organic reactions.
So are biochemical reactions, or drug syntheses, or polymerizations, or...
Online Chemical Equation Balancer Balances equation of any chemical reaction (full or half-cell) in one click.
This looked like improper in regards to WP external link policy.
Finally a reminder: Going too far into adapting content to junior textbooks results in dellusion, even more so for those very juniors.  
--Duplode 03:54, 30 September 2007 (UTC)
thread_title:  Still not quite sharp... 

message: Wikipedia must make up its mind which way to do things.
*Ag2O(s)
*Ag2O(s)
*Ag2O(s)
67.171.43.170 (talk) 05:01, 10 December 2007 (UTC)
thread_title:  Standardized use of (s) (aq) etc. symbols is needed 

message: Under Organic Reactions is this sentence fragment: "Defined in opposition to inorganic reactions."
I would think that inorganic reactions are defined in opposition to organic reactions, if anything. Somebody more knowledgeable than me should either delete the fragment or write it as a complete sentence and expand it a bit. Ronstew (talk) 05:59, 9 February 2009 (UTC)
thread_title:  "Defined in opposition to inorganic reactions"? 

message: To the best of my knowledge, the mechanism for the Baeyer-Villiger oxidation in the equation section is wrong. For one, the protonation of the tetrahedral intermediate cannot be concerted with the attack and moreover there is good evidence that it never occurs, with collapse of the tetrahedral intermediate occuring without proton transfer from the peroxy group to the carbonyl oxygen.
Thoughts? Mdlevin (talk) 04:41, 15 December 2010 (UTC)
thread_title:  Equation Section 

message: The article currently says: Oxidation is better defined as an increase in oxidation number. Looking at oxidation number I get the impression that this expression is used for a rather constrained range of phenomena and that oxidation state fits better to the context in this article. --Ettrig (talk) 16:13, 18 March 2011 (UTC)
thread_title:  Oxidation state or number 

message: Is a "Men in Trees" episode significant enough relative to "chemical reactions" as they are understood here to warrant a redirect at the top of the page?  I can't imagine anyone who'd say it was.  Maybe if the television show itself was called "Chemical Reactions," but an episode?  — Preceding unsigned comment added by 67.5.27.225 (talk) 09:50, 3 May 2012 (UTC)
replies: text: I agree that it is unnecessary and have removed it.  -- Ed (Edgar181) 11:41, 3 May 2012 (UTC)
thread_title: Redirect?

message: I changed the last sentence of this section to more accurately state the situation.  It is based on the college text by Zumdahl & Zumdahl covering this subject.  They carefully distinguish between the equilibrium condition, and the equilibrium position. Thermbal (talk) 04:20, 20 June 2013 (UTC)
thread_title:  Chemical Equilibrium 

message: In reference to the Boudouard reaction of CO2 + C to form 2CO, this reaction is ENDOTHERMIC at ALL temperatures.  Easy to check this out by going to the FACT-web site, using their Reaction tool-- http://www.crct.polymtl.ca/reacweb.htm.  It's heat of reaction is +172.47 kJ at 298.15 K, and +158.98 at 2000 K.  Also, authors shouldn't cite a heat of reaction without referring specifically to the temperature of the reaction.  Thermbal (talk) 04:41, 20 June 2013 (UTC)
replies: text: I removed the reference to the Boudouard reaction, and replaced it with 2 different reactions.  With temperature, one has a reversal in the enthalpy, the other has a reversal in the sign of log Keq, which is equivalent to a change in the sign of the standard Gibbs free energy of the reaction. 
Suggestion:  article editors/writers are urged to include, for each chemical reaction, wherever written in Wikipedia, phase descriptors.  Subscripts like (g) and (s) tell the reader whether the species in a reaction is a gas, a solid, or what.  Thermbal (talk) 19:38, 18 July 2013 (UTC)
thread_title:  Thermodynamics 

message: If metal-acid reaction redirects here (and it does) there really ought to be a clear, easy-to-find subsection on this particular kind of reaction. Maybe I'm missing it, but on a quick scan (with the help of Ctrl-f) I can't actually find anything here about what happens when metals react with acids. --Oolong (talk) 11:46, 2 November 2013 (UTC)
thread_title:  Metal-acid reaction 

message: 197.157.244.227 (talk) 13:08, 13 October 2018 (UTC)
replies: text: Not done: it's not clear what changes you want to be made. Please mention the specific changes in a "change X to Y" format and provide a reliable source if appropriate. L293D (☎ • ✎) 13:10, 13 October 2018 (UTC)
thread_title:  Semi-protected edit request on 13 October 2018 

message: Laxusgajeel (talk) 05:55, 13 November 2018 (UTC)
replies: text: Not done: it's not clear what changes you want to be made. Please mention the specific changes in a "change X to Y" format and provide a reliable source if appropriate. DannyS712 (talk) 06:25, 13 November 2018 (UTC)
thread_title:  Semi-protected edit request on 13 November 2018 

message: I am not a science expert but the section for types has a header that says "four basic types" then lists synthesis, decomposition, single-replacement, double-replacement, and combustionm which are five types. Not sure if the number of types of reactions is wrong or the list of types is wrong but this is confusing. AaronY (talk) 11:15, 24 March 2021 (UTC)
thread_title:  Chemical reactions section lists the wrong number of reactions 

message: Please add an another characteristic of chemical reaction "Change on colour" 114.134.20.99 (talk) 16:35, 21 August 2021 (UTC)
replies: text: Not done: it's not clear what changes you want to be made. Please mention the specific changes in a "change X to Y" format and provide a reliable source if appropriate. ScottishFinnishRadish (talk) 17:40, 21 August 2021 (UTC)
thread_title:  Semi-protected edit request on 21 August 2021 

message: Photosynthesis 41.114.128.75 (talk) 15:39, 3 February 2022 (UTC)
replies: text: The article does have a section on Photochemical reactions. Dirac66 (talk) 18:41, 3 February 2022 (UTC)
thread_title:  Natural sciences 

message: Vh 2A03:2880:30FF:16:0:0:FACE:B00C (talk) 15:30, 25 March 2022 (UTC)
thread_title:  Chemical reactions, composition and decomposition 

message: Oxidation and reduction reaction 197.215.29.102 (talk) 20:43, 25 November 2022 (UTC)
thread_title:  Chemistry 

message: In this , you reverted my addition of forward reactions and backward reactions, which are important types of reactions.
I just want to make sure that it would be okay when I add this content again by citing reliable sources, which I will do when time suffices. — CrafterNova [ TALK ] [ CONT ] 03:47, 10 April 2023 (UTC)
replies: text: I could not find a chemical equation for "charging a normal DC battery (consisting of electrolytic cells) from an external electrical power source". Can anyone help? — CrafterNova [ TALK ] [ CONT ] 18:07, 11 April 2023 (UTC)
thread_title:  Forward and backward reactions  

message: A chemical reaction and a chemical change is the same thing. Since chemical change has very small amount of content, merging it with chemical reaction won't put undue weight (WP:UNDUE) or overload the target article, but any redundancy in text should be reduced as much as possible per WP: REDUNDANCY. — CrafterNova [ TALK ] [ CONT ] 07:27, 12 May 2023 (UTC)
replies: text: I don't agree with it,they are same with a little difference.chemical changes means change in chemical structure of a substance while chemical reaction is a process by which this change happens.So merging a change with a process with ideology that they are same isn't a wise decision AryanpateI (talk) 05:37, 29 July 2023 (UTC)
replies: text: I do not agree with the above. Chemical change is widely used to be more than just change in chemical structure of a substance. It used to be that but it is also frequently used to mean the same as chemical reaction, so merge. --Bduke (talk) 06:51, 29 July 2023 (UTC)
replies: text: A chemical reaction is an effect: something that happens. A chemical change is an affect: the RESULT of an effect. They are distinctly different, albeit related. Regardless, they're different enough that separate pages can be warranted. 2600:6C40:5F00:B1:DF2:5317:6E75:5D1 (talk) 05:05, 15 August 2023 (UTC)

text: Support merge, on the grounds of short text and context. That is, Chemical change is short, and better discussed in the context of the better-developed chemical reaction page. It's of course accepted that these are different thing (transition and final state), but they are so closely related that they are best described in one place. There is already overlap - for example, the Chemical change#Types mostly discussed reactions. Klbrain (talk) 14:54, 18 November 2023 (UTC)
thread_title:  Proposed merge of [[Chemical change]] into [[Chemical reaction]] 

message: An change in color 112.120.127.168 (talk) 12:08, 4 December 2023 (UTC)
replies: text: Not done: it's not clear what changes you want to be made. Please mention the specific changes in a "change X to Y" format and provide a reliable source if appropriate. RudolfRed (talk) 17:06, 4 December 2023 (UTC)
thread_title:  Semi-protected edit request on 4 December 2023