Talk:Equivalent (chemistry)

Suggestions
I'd like to suggest three things 1.One example can be appended following the two indented definition. The example I found in one book is as follows: 6e-+14H++Cr2O72- -> 2Cr3+ + 7H2O In this example, 1 equivalent of K2Cr2O7 is said to be one sixth of a mole( and I think it may be said that 1 mole of K2Cr2O7 is 6 equivalents, though I have not verified whether an s should be appended to equivalent in convention ). My interpretation is that because in this redox reaction, 6 elctrons are used to reduce the chromium in one mole of K2Cr2O7 from 6+ to 3+, we get 6 equivalent(s). It will be nice if someone can explain from both lewis acid-base point of view and bronstead-Lowry acid-base point of view how this equlivalent number is obtained. Otherwise, the reader can be slightly distracted by the fact that both protons and electrons are present in the formula. The refernce book I have is a 1978 version of "Chemistry a conceptual approach" by Mortimer. However, I did not find it's ISBN (possibly due to ISBN was still in its nascency around that time). Therefore, if someone can find a more recent citation with relative easy. I'd like to see it updated.

2. I'd also like to suggest inserting a couple of lines of caveats following the line right under the two idented definitions. That is, we can put a clarification that "equivalent weight" does not carry the unit of conventional weight, being mass times acceleration, rather, it has the same unit as the "mass" does. For readers who are interested in that topic, they will follow the link; for readers who are not, they'll feel much more at ease following the article and trusting the content.

3. There is a semi-mirror page of the article in traditional chinese character version. So if we can put 化學當量, it will increase the linguistic linkage of this page. — Preceding unsigned comment added by 111.248.52.212 (talk) 11:30, 21 September 2011 (UTC)

Conflicting descriptions
at one point in the article it states "So, if 1 mol of NaCl and 1 mol of CaCl2 are dissolved in a solution, there is 1 Eq Na, 1 Eq Ca, and 3 Eq Cl in that solution." then later it states "For example, 1 mmol of Na+ is equal 1 meq, while 1 mmol of Ca++ is equal 2 meq."

in the first example, 1 mol of Ca2+ is 1 equivalent, in the second 1 mol of Ca2+ is 2 equivalents

more conflicting descriptions
It also states one mole of CaCl2 gives 3 equivalents of chloride. Surely it's 2 equivs? as there is one mole of -Cl2, therefore 2 moles of Cl (which has a valence of 1), and therefore 2 x 1 = 2 equivs of Cl in CaCl2. Im not a chemist, so posting here as im not 100% sure. — Preceding unsigned comment added by Forgetful5434 (talk • contribs) 09:53, 5 June 2019 (UTC)

Fixed conflicting descriptions
The example was initially deficient in the wording, and the number kept getting changed back and forth between "1 Eq Ca" and "2 Eq Ca" - the latter being correct.

I added the bold text below to make it clear and hopefully prevent it from being changed back to "1 Eq Ca" which is incorrect:

"Given this definition, an equivalent may also be defined as the number of moles of a given ion in a solution multiplied by the valence of that ion. So, if 1 mol of NaCl and 1 mol of CaCl2 are dissolved in a solution, there is 1 Eq Na, 2 Eq Ca, and 3 Eq Cl in that solution. (Note that the valence of Ca is 2, so for that ion you have 1 mole and 2 equivalents.)" --Pcmoorenm (talk) 20:36, 9 April 2016 (UTC)

Untitled
This article could be difficult for readers to understand without a background in chemistry. 69.140.157.138 09:58, 24 June 2006 (UTC)

This Article should have be the same as Equivalent_Weight

Definition is wrong?
Consider this sentence in the article: "Hence, the equivalent weight of a given substance is effectively equal to the amount of substance in moles, divided by the valence of the substance." This seems to me to give a unit completely different from the unit in the previous paragraph (number of grams that will react with a gram of hydrogen). Consider two elements each with valence 1 but one has very heavy atoms and one has light atoms. The number of moles of each will be the same. But the number of grams that will react with hydrogen will be quite different. Could someone who knows this topic please fix this so that the two definitions are actually equivalent, or else change the article to state clearly that the term can refer to quite different units? Or explain in simple language in the article itself why (I'm wrong and) the two are actually approximately equivalent? Thanks. --Coppertwig 17:12, 31 December 2006 (UTC)

Definition corrected, article is different to equivalent weight
I have sorted out the incorrect definition and added a link to equivalent weight, which is related, but not the same. The formula is now consistent with the example conversion and hopefully now the article makes more sense.

I would suggest that this is kept a separate article to equivalent weight as the two are related but often used in different contexts so it would become more confusing to try to explain the two in one article. RobWB 10:38, 19 January 2007 (UTC)

I have a problem with the following definition of "equivalent"
The equivalent is formally defined as the mass in grams of a substance which will react with 6.022 x 1023 electrons.

To me, this definition looks more like "equivalent weight" than "equivalent" because it deals with mass. In the "conversion guide", there are examples of one equivalent being equal to one mole, half a mole, or one third of a mole. Mole is a number, not mass. For a divalent ion, is one equivalent equal to half a mole of the ion or half of the ion's atomic or molecular weight? To me, it is the former. The latter is called equavilent weight.

I suggest the following definition of equivalent.

An equivalent is defined as the number of moles of a substance which will react with one mole of electrons.

Ctchou 00:41, 23 March 2007 (UTC)

Connection to normal concentration
The connection between equivalent and the normal concentration, although not explicitly detailed in the articles, is that the normal concentration is the equivalent(s) concentration from a volume of solution, exactly in the same way as the molar concentration is actually amount (of substance) concentration.--5.15.201.244 (talk) 14:40, 19 October 2013 (UTC)

Assessment comment
Substituted at 14:35, 29 April 2016 (UTC)

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Backwards definition of milliequivalent
A milliequivalent is 1/1000th of the gram equivalent weight because the gram equivalent weight is so large relative to biologically relevant values. The article says the opposite. 71.10.201.143 (talk) 19:31, 4 April 2020 (UTC)
 * You're absolutely right. I've fixed it. - Dave314159 (talk) 18:41, 18 May 2020 (UTC)

Merger proposal
I propose to merge together Equivalent (chemistry) and Equivalent weight. The two concepts are substantially overlapping, and the content from one article could easily be included in the other. I'm not at all sure which article should be merged into the other, however. - Dave314159 (talk) 18:34, 18 May 2020 (UTC)


 * Agree. Yes, the two articles are on the same topic. I would favor merging Equivalent (chemistry) into Equivalent weight, because Equivalent weight seems a better name, and also because the Equivalent weight seems more complete and better written at the moment. Dirac66 (talk) 20:01, 18 May 2020 (UTC)


 * Disagree. The concept of equivalents is a broader term than just applying to weight (for instance it applies to the stoichiometry of a chemical reaction).  While I agree that the Equivalent weight page is written much better, Equivalent (chemistry) is still appropriate in its own right.  Please do not merge these pages. Stuchalk (talk) 18:14, 4 August 2020 (UTC)


 * Disagree. I completely agree with the user above. neewbie404 (talk) 11:50, 4 October 2020 (UTC)  — Preceding unsigned comment added by 103.197.224.67 (talk)