Wikipedia:Reference desk/Archives/Science/2018 August 8

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August 8

Chemical formulas (C25H35NO5)

N is a nitrogen atom, O is oxygen, every unlabelled vertex or tip you see is a carbon (which could be represented by C, but not in this style of diagram), and finally, there are hydrogens covering most of the atoms so that every C has four bonds, and every N three. (A hydrogens on O is drawn explicitly as OH when applicable) Rings with apparent double bonds are actually aromatic rings. Wnt (talk) 15:18, 8 August 2018 (UTC)

Hi, I was recently given some Mebeverine to take by my doctor and was reading about it on WP. I note the Chemical formula of this drug is C25H35NO5. As I know nothing about chemistry I was just wondering, does this mean my medicine contains Nobelium? or some kind of Nitrogen/Oxygen mix? I am a complete newbie to chemistry so apologies if this seems a very elementary, or even ridiculous question to be asking. I am just trying to understand what this formula means in reality, so any, even simplistic pointers would be most appreciated. Uhooep (talk) 10:57, 8 August 2018 (UTC)

No, it does not. The symbol for Nobelium is No, not NO. The distinction between capital letters and lower case letters is VERY IMPORTANT. A two-letter symbol is always written with a capital letter first and a lower case letter second. If you see two capital letters in a row, that means two different elements. A capital letter in the formula indicates a distinct element, and the number 1 is not written if there are just one of that element in the compound. So C₂₅H₃₅NO₅ means twenty-five carbons, thirty-five hydrogens, one nitrogen, and five oxygens. Wikipedia has articles titled Symbol (chemistry) and Chemical formula if you want more information. --Jayron32 12:45, 8 August 2018 (UTC)

The diagram of this chemical in the Mebeverine (top–right of the whole article) helps illustrate the location of the one nitrogen and five oxygens (and no nobeliums). These sorts of skeletal diagrams might not be generally meaningful to lay readers, but they can help reinforce some formula details. DMacks (talk) 13:44, 8 August 2018 (UTC)

I've added this above. Wnt (talk) 15:18, 8 August 2018 (UTC)

The chemical formula tells you basically nothing about the molecule. Virtually all organic molecules are just carbon, hydrogen, oxygen, and maybe nitrogen arranged in different ways. Sometimes there's an extra element or two thrown in for variety. To know anything about how it behaves, both on its own and in vivo, you need to analyze its structure. This is why chemists use things like structural formulas. As the article states, mebeverine is an analog of papaverine. It is believed to work by antagonizing muscarinic acetylcholine receptors and probably also blocking some calcium channels in smooth muscle. It may have other targets as well—not surprising as papaverine appears similarly "dirty". --47.146.63.87 (talk) 07:05, 9 August 2018 (UTC)

The chemical formula can be informative. For example, this search brings up mebeverine as hits 2, 3, and 5. One of those is a ChemSpider hit,[1] though oddly, the #1 hit - the ChemSpider search itself doesn't link to that! Well, their computer problems aside, the formula would find you the compound you wanted, among some isomers. You can also do little tricks like say C gets 25 x 2 = 50 half bonds beyond what is needed to make a chain, plus 2 at the ends (52). Adding an N anywhere in the structure adds one more place for a hydrogen. Unless double bonded, O doesn't affect anything (C-H to C-OH needs no hydrogen). So if we take 53 half bonds pointing out from the non-hydrogen atoms and tack on 35 hydrogens, that leaves 18 half bonds unaccounted for, which have to be attributed to some kind of looping back of the structure, either double bonds or rings. And if you look, there are 7 double bonds + 2 rings! This sort of empirical formula watching is most useful for determining structure when there aren't any left over, but it is part of the deduction in any case. Wnt (talk) 14:02, 10 August 2018 (UTC)

We have a Degree of unsaturation article:) DMacks (talk) 14:14, 10 August 2018 (UTC)

Can anybody identify this insect?

Unidentified flying insect found in southern France, Gers region

It was approximately 5cm in length, and would occasionally buzz its wings. It did not actually fly whilst I was observing it, which was not for long as someone stood on it. — PhilHibbs | talk 13:47, 8 August 2018 (UTC)

Mole cricket most likely. They typically hang around in summer. Brandmeister^talk 14:15, 8 August 2018 (UTC)

Thanks, looks very like Gryllotalpa africana. — PhilHibbs | talk 14:55, 8 August 2018 (UTC)

Could also be a Jerusalem cricket. --Jayron32 14:56, 8 August 2018 (UTC)

Nah, not in the south of France (see notation under picture); besides the morphology is all wrong. Looking at the distinctive features of the head and prothorax in particular, I would say Brandmeister hit the nail on the head. Based on the aggregate clues, we seem to have two likely contenders for the exact species: the very common European Mole Cricket, Gryllotalpa gryllotalpa, and the less common (but notably also a native of southern France) Gryllotalpa vinae. The afore-mentioned Gryllotalpa africana is sometimes found in Europe, but I can find no source that reports sightings in France (they seem to be confined to rare sightings in Portugal in the West and the Caucus region and Eastward). Snow ^{let's rap} 01:42, 9 August 2018 (UTC)