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Naming MORE branched-chain alkanes
I created this molecule in molview.org with the intent of a 9-carbon parent chain (the horizontal chain in the image) featuring the four 4-carbon alkyl groups: BUTYL, ISOBUTYL, SEC-BUTYL, and TERT-BUTYL). When I proceeded to figure out this structure’s name, I realized the longest parent chain actually has 12 carbons: the leftmost butyl group contains three more carbons than the single methyl group branching from the 8th carbon. So this would be a DODECANE. From there, I had to designate a carbon as #1 in the chain, and the rightmost carbon was chosen because the first substituent would then be on the 3rd carbon; if the chain had been numbered the opposite way, with the top-leftmost carbon being #1, then the first substituent would be the methyl on carbon #5.
With the parent chain identified, the 4 substituent groups are TERT-BUTYL, SEC-BUTYL, ISOBUTYL, and METHYL. HOWEVER, my 2014 organic chemistry textbook apparently didn’t get the memo that some of these names are no longer preferred: sec-butyl became butan-2-yl and isobutyl became 2-methylpropyl (tert-butyl is still the preferred IUPAC name). Hyphenated prefixes (tert- and sec-) do not affect alphabetical order, so these groups are listed as butan-2-yl, tert-butyl, methyl, and 2-methylpropyl.
Although I could not find this molecule online, I’ll take a crack at its name:
6-butan-2-yl-3-tert-butyl-8-methyl-7-(2-methylpropyl)dodecane
OR perhaps
6-(butan-2-yl)-3-(tert-butyl)-8-methyl-7-(2-methylpropyl)dodecane, with added parentheses for clarity.
I suppose one of the fun parts about posting scientific material online is the chance for me to learn more as I try to inform others. Thus, any input from readers/followers about naming this molecule is greatly welcomed and encouraged. I am also very curious if this molecule really exists. This post also highlights the utility of 2D figures. Imagine trying to come up with the name of this molecule with only the 3D figure!
8/16/2018
Molecular formula: H2SO4
pKa: -9 (very strong acid)
Ka (acidity constant) increases with increasing acid strength.
But pKa (-log(Ka)) has an inverse relationship with acid strength.
Sulfuric acid with pKa -9 is much stronger than hydrofluoric acid (HF) with pKa 3.2.
The green bonds are double bonds and the white bonds are single bonds; double bonds are shorter and more rigid than single bonds.
Original image.
#organicchemistry #chemistry #acid#sulfuricacid #hydrofluoricacid #atoms#atom #molecules #molecules #acids#bases #acidstrength #pka #acidity #base#molecularstructure #sulfur #oxygen#hydrogen #bonds #bond #covalent#corrosive #electrons #proton #protons#science #education #fruitgushers#petroleum
7/28/2018
Example: 4 carbons in butane
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#organicchemistry #chemistry #catenation#series #carbon #hydrogen #covalentbonds#butane #education #science #molecule#molecules #atom #atoms #element#elements #periodictable #physics #electron#electrons #chemicals #artsy #bond #bonds#bonding #chemicalbond #physicalscience#fuel #propellant #flammable
7/25/2018
organic_chemistry_daily XENON DIFLUORIDE has a steric number of 5. As with ammonia and water (see previous IG posts), lone pairs of electrons are counted when calculating steric number; there are 3 lone pairs around the central xenon, plus the 2 fluorine atoms covalently bonded to xenon.
The lone pairs spread out from each other in such a way that the F-Xe-F bond angle is 180°, allowing XeF2 to be classified as a LINEAR molecule.
Yes, technically this is not "organic" chemistry! But a triatomic organic compound with SN=5 and three lone pairs would exhibit a similar shape, assuming the two surrounding atoms were the same element.
Image is a screenshot from molview.org
#organicchemistry #chemistry #molecule#molecules #atom #atoms #xenon#fluorine #geometry #moleculargeometry#science #education #linear #stericnumber#electron #electrons #lonepairs #repulsion#vsepr #vseprtheory #bond #bondangle#jamesbondangle #angle #covalent#covalentbond #structure #physicalscience#inorganicchemistry #inorganic
7/24/2018
organic_chemistry_daily CARBOCATIONS are Lewis acids: they readily accept electron (e-) pairs. The positively-charged carbon atom is electron-deficient because it only possesses six valence shell electrons; this unstable sextet also makes carbocations short-lived and highly REACTIVE. However, if the carbocation accepts a Lewis base’s e- pair donation, the stable octet is achieved. This stability is much more desirable than the sextet, explaining why this chemical species is so reactive and eager to obtain an e- pair. Note how carbocations could not be considered Brønsted-Lowry acids because they do not donate a proton when accepting an e- pair.
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Just to further explain the positive charge: the lack of negatively-charged electrons gives the carbon a positive charge in much the same way as subtracting -1 from 2 equals 3
2 – (-1) = 2 + 1 = 3
Losing a negative charge in effect creates a positive charge.
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#organicchemistry #chemistry #acids#bases #acidbasechemistry #electron#electrons #valenceshell #octet #sextet#noblegas #electronconfiguration#electronpair #science #education#reactive #carbon #carbocation #proton#charge #formalcharge #atom #atoms#molecule #molecules #Lewisstructure#ion #ions #anion #cation
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7/22/2018
organic_chemistry_daily LEWIS acids are defined as electron pair acceptors while BRONSTED-LOWRY acids must specifically donate a proton; the former definition is broader, and thus Lewis acids encompass many substances that include Bronsted-Lowry acids.
In the HCl example in the image, this inclusion is evident. The proton of HCl is colored green to emphasize the B-L definition, but the HCl is also accepting an electron pair from NH3. Both definitions can apply to HCl. Cl3Al is accepting these same electrons, but it is not donating a proton to NH3 in the process. This illustrates how the Lewis definition is broader than the more particular B-L definition.
#organicchemistry #chemistry #education#acids #bases #lewisacid #acidbase#electrons #protons #reaction#reactionmechanism #bronstedlowry#diagram #chemicalreaction #ph #bond#bonds #aluminum #chlorine #nitrogen#hydrogen #ammonia #science #electron#atoms #molecules #atom #molecule#compound #substance
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7/22/2018
organic_chemistry_daily Ammonia has the same steric number (SN) as methane: 4. Why 4? Because the steric number is the sum of atoms/groups/lone pairs around a central atom. The N of ammonia is bonded to 3 H atoms as well as to a lone pair of electrons (not shown in image above) --> 3 atoms + 1 lone pair = SN = 4.
But hold on! The molecular geometry of ammonia is not the same as that of methane! Lone pairs are not included in molecular shape, so ammonia's central N and 3 H atoms create a TRIGONAL PYRAMIDAL shape. Furthermore, the lone pair actually repels the 3 covalent bonds to a greater extent than a 4th covalent bond would; this is why the H-N-H bond angles of ammonia are actually less than the 109.5° H-C-H angles in methane. The lone electron pair forces the bonding electrons closer together, thereby reducing the bond angles to 107°.
#organicchemistry#chemistry #ammonia #trigonalpyramidal#lonepair #repulsion #education #science#vsepr #vseprtheory #vseprmodel#methane #molecule #molecules#moleculargeometry #geometry#molecularshape #bondangle #bondangles#jamesbondangle #jmol #nitrogen#hydrogen #compound #gas #electrons#atom #atoms #covalentbond #college
Image from mn-am.com
7/18/2018
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