# Tag Info

23

First part It won't decide the issue but the Organic Chemistry text by Clayden, Greeves, Warren and Wothers also mentions that the matter might not be as clear-cut as the majority of your textbooks make it seem. This might strengthen the position of the textbook you're using a bit. But again, there are no references given. Here is the relevant passage (...

19

So, shouldn’t the order be the other way round? Yes, it is the other way around. Ketones (pKa ~ 20) are more acidic than esters (pKa ~ 25). The figure below shows the resonance structures for the enolate anion of a ketone and an ester. Resonance structures II and IV stabilize the enolate anion in the ketone and ester respectively. In the ester, there is ...

16

Extending the pattern of epoxides to bromonium ions and mercurinium ions is hazardous at best. Below the second row (the carbon row) bond lengths get much longer, and acid strengths are much lower than compared to sulfuric acid in methanol. In general acid-catalyzed reactions involving epoxides where selectivity is a concern will have carbocation ...

14

It is quite well established that stoichiometric gallium arsenide (CAS 1303-00-0) forms a zincblende analogous structure. It consists of two stacked face-centered cubic lattice systems (Ioffe Physical Technical Institute database). See also Uncle Al's Answer. In other words, the arsenic forms the lattice and the gallium fills half of the tetrahedral ...

13

The two-dimensional representations you have given are inadequate and should not be taken too seriously; crystal structures are nearly always three-dimensional. Gallium arsenide has the cubic zincblende structure, shown below. Here, blue atoms can are Ga and orange atoms As (it can be the other way round, too, as these atoms are related by symmetry). (Image ...

13

Interestingly, IUPAC states that a "salt" is "a chemical compound consisting of an assembly of cations and anions". Under this definition, all ionic compounds are salts, and all salts are ionic compounds. Therefore, something like sodium hydroxide ($\ce{Na+OH-}$, definitely an ionic compound) could actually be correctly called a salt. This clashes with the ...

12

You are confused because the answer key is wrong. The way to figure it out is to assign oxidation numbers to each species following the rules. Oxidation states are simply a convenient way to keep track of electrons without having to draw out Lewis structures, count electrons pairs and so on. The rules help make that happen. Notice the position of the sign ...

12

You are actually right, that stereocenter does have R stereochemistry. The four substituents to the chiral center in question are: 1 - $\ce{CO(O)}$ = $\ce{C(O)3}$ 2 - $\ce{C(O)(C)(H)}$ 3 - $\ce{C(N)(C)(H)}$ 4 - $\ce{H}$ These are ranked and numbered according to the Cahn-Ingold-Prelog priority rules. Adding the numbering to the structure: Orienting the ...

11

I can understand your frustration. The use of terminology is often inconsistent and confused (much to my chagrin). I think you've got the general idea, the conductance ($G$) can be defined as follows: $$G = \frac{1}{R}$$ i.e. the ease with which a current can flow. As you said, $$R = \rho \frac{l}{A}$$ one can now identify, $$G = \kappa\frac{A}{l}$$ ...

10

The somewhat standard reference (~1800 citations in Google Scholar) for bulk GaAs structure is a 1982 paper by J. S. Blakemore: J. Appl. Phys. 53, R123 (1982). The experimental/numerical data in it (via X-ray diffraction) establishing the crystal structure of bulk GaAs goes back to the 1960s though. One of the more helpful visualizations of zincblene ...

10

According Kinetics, Mechanism, and Spectroscopy of the Reversible Binding of Nitric Oxide to Aquated Iron(II). An Undergraduate Text Book Reaction Revisited The correct structure is $\ce{ [Fe^{III}(H_2O)_5(NO^{-})]^{2+} }$ For many years it was thought that iron was reduced to Fe(I) and NO oxidized to NO+, based upon an observed magnetic moment suggestive ...

10

There are 2 methyl groups on the second carbon of the main chain, and 1 methyl group on the fourth carbon of the main chain, so 2,2,4-trimethylpentane is correct! If there was a methyl group on the 5th carbon of a pentane, it would be a hexane, so it would not make sense to name it the way your book did.

9

The equation is a little dubious, as I mentioned in the comments. How do we come up with coefficients of this sort? Let's go from scratch. We don't know the coefficients at this point so we'll just call them $a$, $b$, and $c$. Note that the coefficient of $\ce{S$_x$H$_y$O$_z$}$ is taken to be 1. It doesn't have to be 1; however, for the sake of ...

9

the whole reaction, i.e. for 2 moles of the product? This is your mistake. The balanced equation $\ce{2H2 + O2 -> 2H2O}$ does not mean that 2 moles of the product are being formed. The numbers, called stoichiometric coefficients, only tell you about the ratio in which the reactants react and form products. That is to say, if I had a system in which I ...

8

Short answer: $\lambda = z \mu F$ is correct. The link provided by @Loong confirms this (page 73 of the document). To add to that I have provided you with a short derivation. Prerequisite reading (so to speak) for definitions of a few terms/notation would be my answers to this question, and this question Let me establish an important distinction (or ...

8

The Ph.D. thesis that is cited is probably near-impossible to obtain and may very well be in Japanese, which certainly doesn't help. 2-Phenylethanol is not a chiral compound, so as Ivan pointed out, the concept of enantiomeric excess (ee) makes no sense. The fact that the direct reduction product of acetophenone (e.g. via hydride transfer) is 1-...

8

The book means to say that there are 2 electrons in the $\mathrm{3s}$ subshell and and 2 electrons in the $\mathrm{3p}$ subshell. You can see this in the electron configuration as $\mathrm{...3s^2 3p^2}$ and that the maximum configuration has 2 electrons in the $\mathrm{3s}$ subshell and 6 electrons in the $\mathrm{3p}$ subshell which would be $\... 8 Concur with this point: "$\ce{2s}$and$\ce{2p}$valence electrons" is not the same thing as "two$\ce{s}$and two$\ce{p}$valence electrons". Your book probably used the latter, but you interpreted it as the former. Though, it is entirely possible that the book wrote it the way you say it had, but unless you quote that particular line and cite the book ... 8 This should never have happened in the scientific community, but: The energy values of food are measured by the Calorie, with a capital C. A Calorie is equal to 1,000 calories or 1 kilocalorie (kcal). Source: here It is possible that Barron's got confused between Calorie and calorie. Even so, they still would be off by a factor of 100. According to ... 8 I suspect MolView simply fails to parse the compound's name you are trying to input. "Hydroxypropadiene" isn't the proper name, at least not by IUPAC standards. According to Google services, this name doesn't appear in any textbooks and is mentioned only in three research articles from 1980s. The PIN propa‐1,2‐dien‐1‐ol appears to work correctly with ... 7 You are not mistaken. Your book is wrong. If one desperately wants to involve the hybridisation concept (which makes sense for carbon), then the description should be in accordance with the molecular geometry of ethene: So the carbons can be described as$\ce{sp_{x}p_{y}=sp^2}$hybridised, hence there are four$\ce{H_{s}-C_{sp^2}}\sigma$bonds, one$\ce{...

7

I ran the calculations through the MATLAB command window and obtained the same answers as you: >> H = [-13.60 -14.18 0; -14.18 -13.60 -14.18; 0 -14.18 -13.60] >> S = [1 0.596 0; 0.596 1 0.596; 0 0.596 1] >> energies = eig(H,S) energies = -18.2615 -13.6000 41.0717 On the other hand, if you assume that $S_{12} = 0$ i.e. $S = I_3$ (...

7

According to NIST Chemistry Webbook, for oxygen: $$T_\mathrm{boil} = \pu{90.2\pm0.2 K}$$ $$T_\mathrm{fus} = \pu{54.8\pm0.2 K}$$ $$T_\mathrm{triple} = \pu{54.33\pm0.6 K}$$ The $T_\mathrm{boil}$ and $T_\mathrm{fus}$ are from Ref.1 while Brower and Thodos reported $T_\mathrm{triple}$ as $\pu{54.363 K}$ at pressure of $\pu{1.125 mmHg}$ (Ref.2). The ...

6

As you point out, the $\ce{B}$ in $\ce{BF_3}$ is sharing a total of 6 electrons, 3 from the boron and 3 from the three fluorines. Now add a fluoride anion that brings 2 more electrons to share. This now makes for a total of 8 electrons around the boron.

6

These authors are comparing relative energies. Look at what they set as their reference... the products. They could have easily made "starting materials" as their 0.0 reference point and stated that the products of the acyl chloride reaction is lower in energy relative to the anhydride reaction mechanism.

6

I'm not sure where you get the idea that glass is linear. What makes a glass is the lack of long range ordering, though in fused silica, the approximate tetrahedral structure of $\ce{SiO4}$ is maintained (this is a 2D section, the fourth oxygens are not shown): Source In normal glasses, there is no significant net dipole moment across the entire structure,...

6

This is not a complete answer (merely a step in a particular direction, namely that of the falsehood of the claim), but I contacted the author of the book (Introduction to Medicinal Chemistry) Graham Patrick and he wrote the following: Dear Jori, Many thanks for your e-mail and observations. Unfortunately, that statement was made in a very early ...

6

As a former contributor to Orca who had access to Turbomole sources before that, I can say with confidence that the internal definitions of B3LYP and B3LYP_gaussian are consistent among them and Gaussian (where available). So no calculations should go wrong. While I cannot speak for Gaussian, for Orca I am certain that the ScalLDAC parameter is badly ...

Only top voted, non community-wiki answers of a minimum length are eligible