Talk:Hess's law

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Comment[edit]

I changed the solution after I noticed The author forgot to multiply the third equation by 3 Please check me!. (he wrote this needs to be done, but it wasn't done in the calculations, so I also changed the final answer.) again.. check me. hey

the 4th equation of the example is wrong and doesnt give a value for energy. ... H= ? Kj

The example is unsolvable as given. There is no linear combination of the first 3 equations that can result in the 4th. Thegeneralguy (talk) 16:16, 11 October 2008 (UTC)[reply]

Proper Grammar for title[edit]

Correct me if I'm wrong, but isn't " Hess's " improper? Should it not be " Hess' "? Minor issue, but it could be fixed.

I think Hess's is still accepted. Not 100% though.

The Oxford Dictionary of Chemistry lists it as Hess's law. Adios:--Sadi Carnot 02:37, 30 July 2006 (UTC)[reply]

Moved stuff here from Talk:Hess' law

"Hess's" is proper, as "Hess" is only monosyllabic. For monosyllabic words ending with an "s", to show possession, one adds "'s". Should the word be polysyllabic, only the apostrophe would be added --AtomicCactus 19:21, 8 November 2006 (UTC)[reply]

Nope your wrong and it wont work.

I'm sure thats wrong AtomicCactus, what about "boys'" which is the usual example for this rule. "St James's Park" is a classic station in london which is incorrect. Wolfmankurd 22:11, 20 April 2007 (UTC)[reply]

To Wolfmankurd

According to the apostrophe protection society, the Oxford Dictionary of Chemistry is wrong. This society is recognized by wikipedia.org and is located here http://www.apostrophe.fsnet.co.uk/

For proper nouns, it is always 's regardless of the ending; therefore, the title is correct as is.

Reprise 2014: Title vs. text[edit]

Currently, the title and the first sentence don't match. Wqwt (talk) 03:41, 17 October 2014 (UTC)[reply]

They don't match because there is no consensus on which spelling is correct. The text including the first sentence was changed from Hess's to Hess' on 17 May 2011 by one editor, but changing the title is supposed to require a consensus. Probably this would require finding an authoritative source. The other examples cited above are not very helpful; e.g. someone said that St. James's Park is wrong. Well, Wikipedia has an article on St. James' Park, but also on St. James's Palace, so which precedent applies here?? Personally, I think that Hess's law sounds much better so I would keep the title and change the text back to Hess's throughout. Dirac66 (talk) 12:54, 19 October 2014 (UTC)[reply]

On further thought, I decided to check my chemistry books as sources for this law, rather than look through dictionaries and grammar books for general laws of English language. Six of seven books (listed below) use Hess's which is a clear majority. One book plus the index of a second use Hess'. So I will leave the article title as Hess's, and change the text from Hess' to Hess's, with a note at the beginning to say that some authors write Hess'.

Here is the list of source books which I checked:

- Atkins P. and de Paula J. Physical Chemistry (8th ed. W.H. Freeman 2006) ISBN 0-7167-8759-8, p.53 - Hess's law
- Bettelheim F.A. and March J. Introduction to General, Organic and Biochemistry (3rd ed. Saunders 1991) ISBN 0-03-030928-X, p.118 - Hess's law
- Engel T. and Reid P. Physical Chemistry (Pearson Benjamin/Cummings 2006) ISBN 0-8053-3842-X, p.68 - Hess's law
- Laidler K.J. and Meiser J.H. Physical Chemistry (Benjamin/Cummings 1982) ISBN 0-8053-5682-7, p.58 - Hess's law. Index - Hess' law
- Laidler K.J. Physical Chemistry with Biological Applications (Benjamin/Cummings 1978) ISBN 0-8053-5680-0, p.158 - Hess's law
- Petrucci R.H., Harwood W.S. and Herring F.G. General Chemistry (8th ed. Prentice-Hall 2002) ISBN 0-13-014329-4, p.241 - Hess's law
- Whitten K.W., Gailey K.D. and Davis R.E. General Chemistry (4th ed. Saunders 1992) ISBN 0-03-072373-6, p.577 - Hess' law Dirac66 (talk) 17:17, 19 October 2014 (UTC)[reply]

Redirects[edit]

Added Redirects from hess' cycle.Wolfmankurd 18:42, 22 May 2006 (UTC)[reply]

Real example[edit]

Can someone please put a real calculation diagram, with real elements, reactants and products? Please? Cherubfish 19:25, 22 May 2006 (UTC)[reply]

I'll get to work on it.

I commented out the picture that goes wiht it becaus eI cant amke it look right. Wolfmankurd 19:41, 22 May 2006 (UTC)[reply]

Page moved[edit]

This article was already started in '03 see: Hess's law. I will move all this stuff there.--Sadi Carnot 02:23, 30 July 2006 (UTC)[reply]

Is it products-reactants or reactants-products?[edit]

I was taught in class that the equation was ΔH(reactants)-ΔH(products), but the article claims it to be ΔH(products)-ΔH(reactants). Which one is correct? --Chanmazap (talk) 03:36, 5 May 2010 (UTC)[reply]

The correct equation is ΔHθ(reaction)=ΣΔH(products)-ΣΔH(reactants) natemonster (talk) 03:46, 4 January 2012 (UTC)[reply]

Application to the heat of formation of isotopes[edit]

An example of application of this law to the determination of standard heat of formation of isotopes (H, D) would be a useful (and interesting) addition to article (of course based on survey of sources with experimental data). This suggestion of content addition has appeared from the discussion at talk:standard enthalpy of formation.--5.2.200.163 (talk) 15:43, 20 October 2015 (UTC)[reply]