Talk:Reaction rate

Apr 2004

When I found this page it was looking pretty ugly. I did my best to clean it up, but since I'm only in a general chemistry course I'm not quite sure about some of this stuff. I'm not so sure it's real, but I'm not so sure it isn't. See Talk:Reaction rate/April 1 cleanup for the material that I took out of the article. Since you probably know more about chemistry than me, it'd be delightful if you could make it pretty and put it back into the article. Thanks! --Alex S 22:26, 1 Apr 2004 (UTC)

Someone ought to explain that "order" thing a bit more thoroughly in the part about the factors that affect the reaction rate. I have no idea what it means. Quirk 17:51, 30 Sep 2004 (UTC)

I think that there should be more about moles per second, just an idea though. Xykon 8:55, 20 Mar 2006 (UTC-5)

Requested Move

It seems that there are a few pages that already explain reaction rates in chemical reactions. This being one of them, another being the page called Reaction rate constant and the third being Rate laws. Both articles can be easily trimmed down and merged into this one. I do not have the understanding or ability to move so much information so I'd appreciate it if someone considered doing so. Aznph8playa 00:25, 30 May 2005 (UTC)

Also Rate equation (chemistry). I say we merge all of them, agree?

Merge from Reaction rate constant

• agree - mastodon 01:14, 16 April 2006 (UTC)
• agree - NHSavage 07:23, 16 April 2006 (UTC)

Merge from Rate laws

• agree - mastodon 01:14, 16 April 2006 (UTC)
• agree - NHSavage 07:23, 16 April 2006 (UTC)

I'm attempting a draft of a merged article at: User:NHSavage/sandbox comments, edits, criticism welcome. It is a bit messy and it will need quite a lot of work yet.--NHSavage 09:50, 16 April 2006 (UTC)

Merge complete. Please let me know what you think. --NHSavage 14:41, 16 April 2006 (UTC)

Fantastic work, very well done :) looks like this article is going to get a lot more traffic now, not that it particually needs it much - mastodon 21:03, 16 April 2006 (UTC)

• This merge is poorly executed. More than one day should pass between merge proposal and actual merge. Also this is an encyclopedia not a textbook so your efforts should go here: http://en.wikibooks.org/wiki/Rates_and_equilibria_%28Organic_chemistry%29 in Wikibooks. Also some content is actually deleted in the merge. So the end result is LESS wiki content piled together. The merge will get reverted in 24 hours unless the perpetrators fix thing themselves. V8rik 15:46, 17 April 2006 (UTC)

I fail to see the problem but I have reverted anyway. Please also note that the first merge request was over 10 months ago. (30 May 2005). I also resent a being described as perpetrator when I was simply trying to work in the spirit of wikipedia. I leave this article to others. I would also appreciate an explanation of what should be in an encyclopedia article on reaction rates which is different from the content here which you say should be in wikibooks.--NHSavage 16:11, 17 April 2006 (UTC)

For what its worth I'll leave the rejected draft at User:NHSavage/sandbox. --NHSavage 18:46, 17 April 2006 (UTC)

I found your merge pretty good and I have been thinking that it's a mess to have 3 o 4 different articles dealing with two basic concepts: reaction rate and rate equation, which have to be explained together, they are absolutley not independet. Having the info split and repeated in different places only make people confused. If any info is missing it can be added afterwards, i think is more important to have a nice and tidy article to place itKnights who say ni 01:42, 22 April 2006 (UTC)

Can I suggest then that you re-revert this article and the others to my merge? Given that it is now a week since my original merge so I think that part of the original criticism no longer stands.--NHSavage 07:38, 22 April 2006 (UTC)

Go for it - mastodon 22:40, 22 April 2006 (UTC)

OK then given the people egging me on I have re-reverted. I have missed out parts from the original three articles. There was a huge overlap and duplication so it was a real challenge to do the merge. If important concepts have been lost just add them to the newly merged article please. Thanks to Knights who say ni and mastodon for the edits which were done while the article was on my page.--NHSavage 16:38, 23 April 2006 (UTC)

Why do the academicians burger each other...... —Preceding unsigned comment added by Gichireg (talk • contribs) 05:23, 5 January 2010 (UTC)

again poorly executed merge

Again merge poorly executed with deletion of content, something I can find no justification for. My general concerns on deletions and merge see my comments User:V8rik. For this particular merge:

• why not have a general qualitative discussion on reaction rates and leave rate laws as a separate topic with lots of equations.
• there is plenty material to be added to rate laws: third order, broken order, the size of the article will become unmanageable when you also include graphics.

These 2 comments are fair enough once the article grows to a point to justify the separate articles. At present the material does not justify it. Previously the articles duplicated the same information in a confusing way.--NHSavage 20:48, 23 April 2006 (UTC)

• this is not just a merge, content is also added: the equilibrium reactions part

This was originally on this page but was removed, see above and Talk:Reaction rate/April 1 cleanup

• will parallel reactions, competing reactions and steady state reaction also end up on this page?

Steady state (chemistry) has its own satisfactory article. I see no reason to merge with it. Some see also links would be worthwhile. The other two have no articles. If these concepts are important here then add them or write articles on them and link to them from here.--NHSavage 20:48, 23 April 2006 (UTC)

• the Van't Hoff equation is different from what is stated in the article

I will check this in my Physical Chemistry textbook tommorow and correct whichever is wrong. Of course both may be know as the Van't Hoff equation. What is here is the Van't Hoff equation according to the removed material. --NHSavage 20:48, 23 April 2006 (UTC)

According to Atkins the Van't Hoff equation is not the equation I included. Well spotted. Unfortunately it seems that Atkins uses the term for a completely different equation again and calls the equation at Van't Hoff equation the Van't Hoff isochore. The Van't Hoff equation relates to osmostic pressure. I will take this comment there.--NHSavage 16:17, 24 April 2006 (UTC)

Ignore that - 6th Edition of Atkins (not my 3rd edition) uses the term for both equations...--NHSavage 19:56, 24 April 2006 (UTC)

• if you scrap content you cannot just suggest that others should make the corrections, this is the responsibility of the person initiating the merge

I did not scrap content as far as I am aware - in my opinion I removed duplication. You obviously disagee. Please fix it and don't just whinge. Wikipedia is everyones responsibility. You did not bother to explain what was deleted.--NHSavage 20:48, 23 April 2006 (UTC)

As soon as I have time I will look into demerging this article and add actual content V8rik 19:55, 23 April 2006 (UTC)

If there is no conent now there was no content before and at least all the non content is in one place. Stop being so bloody agressive.--NHSavage 20:48, 23 April 2006 (UTC)

I find the qualifications whinge and agressive offensive, I expect better quality people involved with WIki V8rik 21:10, 23 April 2006 (UTC)

I am sorry. I should not have used that language.--NHSavage 20:48, 25 April 2006 (UTC)

No need to merge IMHO

I think part of the merging problem is solved, now we have significantly different articles, which is, i understand, what we all were looking for (having almost the same content in 3 different articles was unacceptable): one for reaction rate which deals more with qualitative concepts and rate equation which deals with a bunch of possible rate equations, the problem is now to fix chemical kinetics, because part of the info on what affects the reaction rate is duplicated and maybe order (chemistry) could be tidied a bit. If you feel like improving anything or moving things please go ahead Knights who say ni 00:36, 24 April 2006 (UTC)

• Hi, Knights who say ni this is a great solution, thanks. In my opinion the chemical kinetics article should present a general overview but not specifics. The factors part can be reduced to one centence: factors are concentration, physical state and temperature etc V8rik 15:57, 24 April 2006 (UTC)

Image for article

User:TimVickers produced the following image which I nominated for deletion last week because it wasn't being used anywhere. User:Deryck Chan was nice enough to look through my nominations at my request and thought that this one was worth saving, and might be useful on this article:

File:MM curve.jpg

~ BigrTex 14:28, 5 February 2007 (UTC)

I just found that it has been replaced by a .png file on commons:

which is in use on Enzyme, so it's not clear to me if this would be useful here or not. ~ BigrTex 16:02, 5 February 2007 (UTC)

This image in svg:

replacing png

--fullofstars

concentration

"Concentration: Reaction rate increases with concentration, as described by the rate law and explained by collision theory. As reactant concentration increases, the frequency of collision increases and so does the fraction of collisions having sufficient energy to cause reaction." Is this true? doesn't the fraction that react stay the same?

True!!! I thought I had corrected that one!!!Knights who say ni 22:47, 21 February 2007 (UTC)

how to .......

how do u make an equation on the microsoft word, —Preceding unsigned comment added by 212.32.72.141 (talk) 15:02, 17 July 2008 (UTC)

type in <math> notation which is derived from TeX. like this:

subscripts and superscripts <math>x_2 + y^2</math> => $x_{2}+y^{2}$

fractions integrals <math>\frac{x+1}{x+1} = \int_{1}^{2}34 dt</math> => ${\frac {x+1}{x+1}}=\int _{1}^{2}34dt$

greek letters <math>\phi - \Phi = \xi + \zeta + \alpha</math> => $\phi -\Phi =\xi +\zeta +\alpha$

See http://meta.wikimedia.org/wiki/Help:Formula

OsamaBinLogin (talk) 23:43, 30 September 2012 (UTC)

Formal definition of reaction rate: huh?

this section confuses me, it seems that they change notation a couple of times?

are these equal?

${\frac {d[A]}{dt}}={\frac {dN_{A}}{dt}}$

The severe case stated previously doesn't seem to exist anymore.

The $\nu _{i}$ are equal to the $a,b,p,q$ from above? OsamaBinLogin (talk) 23:43, 30 September 2012 (UTC)

Good questions which should be answered more clearly in the article. Briefly for now -

1. N_A is the number of molecules of A, while [A] is as stated the concentration of A in moles per litre. They are related by [A] = N_A/N₀V, where N₀ is the Avogadro constant and V the volume.
2. I think the severe case stated previously refers to a closed system at constant volume.
3. You are correct about the stoechiometric coefficents: $\nu _{i}$ is equal to a, b, p, q in the example given. Dirac66 (talk) 00:30, 1 October 2012 (UTC)

I have now inserted these explanations. The symbols in the mass balance equation still need clarification, perhaps by someone with a chemical engineering background.

Contradictory claim elsewhere

As a rule of thumb, reaction rates for many reactions double for every 10 degrees Celsius increase in temperature,[1] though the effect of temperature may be very much larger or smaller than this.

In another Wikipedia article, it states that this is a misconception and that the rough rule of thumb is only valid for biological reactions.

178.38.90.162 (talk) 18:58, 3 April 2015 (UTC)

Where is elsewhere? Which other Wikipedia article, please? Dirac66 (talk) 01:03, 4 April 2015 (UTC)

Q10 (temperature coefficient) mentions deviations from the so-called "rule of thumb" in a biological context (but with a chemical background). Also, de:RGT-Regel states more broadly that the reaction rate increases two- to fourfold every 10 K. Even that is often qualified and restricted to "physiological (see discussion of the topic there). I'd rather not mention this "rule" at all, because its applicability depends on the value of the activation energy and the temperature being considered, such that Q10 increases with the former and decreases with the latter. --Schlosser67 (talk) 13:13, 1 December 2015 (UTC)

I have now moved the "rule of thumb" to the Temperature dependence section as a shortened version. Dirac66 (talk) 02:54, 5 December 2015 (UTC)

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Assessment comment

The comment(s) below were originally left at Talk:Reaction rate/Comments, and are posted here for posterity. Following several discussions in past years, these subpages are now deprecated. The comments may be irrelevant or outdated; if so, please feel free to remove this section.

i have no idea what you are all talking about i just want to know how surface ares effects reaction rates (maybe you could add it in! thanks) anywy i hope you find so,eone to make your "ugly page" pretty soon!!!

Last edited at 15:43, 21 May 2007 (UTC). Substituted at 04:00, 30 April 2016 (UTC)

Article is incorrect

It has been years since I brought this up on wikipedia, but unfortunately text books in chemistry are wrong about what reaction rate is. What text books in chemistry deal with is a special case:

• Closed system
• Only one reaction
• Constant volume
• Perfect mixing

What text books call a "definition" of reaction rate is actually just a special case that comes from a mass balance for an ideal batch reactor

IN + PROD = OUT + ACC

0 + r_AV = d(VC_A)/dt

As an example, in flow systems like your own body, the reaction rate is definitely NOT equal to the time derivative of concentration. The oxygen levels in your muscle can be constant over time. Another simple example: Take a glass of sea water and dilute it with distilled water. The concentration changes, but there is no reaction.

I know I'm like Don Quijote here, fighting an impossible fight. Essentially all text books in Chemistry tell the same story and Wikipedia refers to such text books. The fact that these text books are wrong will likely not matter to most people who edit this article on wikipedia --Saittam (talk) 08:58, 23 June 2021 (UTC)

I think the words "incorrect" and "wrong" are not justified. It is better to say that the article and (some?) textbooks deal with a special case and are therefore "incomplete", which implies that we should keep the present material and add a section (or sections) dealing with a more general case.

If you can find sources (advanced textbooks or published review articles), then go ahead and draft additional sections.

And you might also check the content of other articles in the same Wikipedia categories: Category: Chemical kinetics and Category: Chemical reaction engineering. Perhaps some of the content you can find can be adapted for this article. Dirac66 (talk) 02:10, 1 July 2021 (UTC)

Si unit and dimension

Don't you think we have to include si unit and dimension in article? AryanpateI (talk) 08:54, 15 August 2023 (UTC)

Types of reaction rate

have to include types of reaction rate like average and instantaneous reaction rate. AryanpateI (talk) 14:51, 15 August 2023 (UTC)