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### What is the endo-selectivity of Diels-Alder reactions? ###
If the dienophile alkene used in the Diels-Alder reaction is unsymmetric, then two different isomers of the final adduct can form. The isomer, where the functional group(s) (usually carbonyl) on the alkene end up on the same side as the newly formed doub... |
If you wanted to increase the pH of any acid by 1, how many times should you need to dilute it by? |
I need to prepare the $\pu{1M}$ solution of sodium crotonate, however, I don't have one in lab, but I do have sodium hydroxide and crotonic acid.
Thus, I calculated that for $\pu{100 mL}$ of $\pu{1M}$ solution I need: ~$\pu{4g}$ of $\ce{NaOH}$ and ~$\pu{8.6g}$ of crotonic acid. After preparation of solution (approx... |
I need to prepare the $\pu{1M}$ solution of sodium crotonate, however, I don't have one in lab, but I do have sodium hydroxide and crotonic acid.
Thus, I calculated that for $\pu{100 mL}$ of $\pu{1M}$ solution I need: ~$\pu{4g}$ of $\ce{NaOH}$ and ~$\pu{8.6g}$ of crotonic acid. After preparation of solution (approx... |
### What is the endo-selectivity of Diels-Alder reactions? ###
If the dienophile alkene used in the Diels-Alder reaction is unsymmetric, then two different isomers of the final adduct can form. The isomer, where the functional group(s) (usually carbonyl) on the alkene end up on the same side as the newly formed doub... |
Conducting an experiment, I found that very little salicylic acid was evolved performing hydrolysis at $\mathrm{pH \ 2}$ and at $\pu{45 ^\circ C}$. In fact, far more salicylic acid was evolved at $\mathrm{pH \ 7}$. This comes as a surprise to me because I expected an acid-catalyzed ester hydrolysis to actually quicken ... |
You might look up the decomposition of hydrogen peroxide, $\ce{H2O2}$. The 3% solution sold as antiseptic should be safe to use at home, as would be some readily available catalysts and inhibitors.
[Horseradish][1] might be used for a catalyst... but don't eat it in the lab.
To measure speed of reaction, measure ... |
I thought that this would be easier to find. There are plenty of sources saying that it is air sensitive, and a couple reaction schema that require oxygen, but I can't find what the oxygen actually does. Pd(0) doesn't seem like it would get oxidised in air that easily, does it? |
Why is the Suzuki coupling done under inert atmosphere? |
I thought that this would be easier to find. There are plenty of sources saying that it is air sensitive, and a couple reaction schema that require oxygen. However I'd like to know why it is air sensitive. I cannot find what the oxygen actually does. Pd(0) doesn't seem like it would get oxidised in air that easily, d... |
There are plenty of sources saying that the Suzuki coupling is air-sensitive (even though there are [some versions](https://pubs.rsc.org/en/content/articlelanding/2011/ob/c0ob00524j#!divAbstract) that require oxygen). However I'd like to know why a typical Suzuki coupling is air-sensitive. I cannot find what the oxygen... |
Why does iron oxide form hydrous iron oxide while chromium oxide does not? |
Without knowing the Average Atomic Mass or the percent abundance, how do we know that Protium is the most prevalent hydrogen isotope? What methods did scientists use to come to this conclusion? How did they reach such a conclusion?
I'm still starting out in learning chemistry and I felt like I hit a boulder. I know ... |
How do we know the natural abundance of isotopes on Earth? |
> If I want to increase the voltage, which electrolyte do I change?
Hope you are familiar with the term *electrolyte* which is the solution where ions flow in the electrochemical cell
[![Galvanic Cell][1]][1]
[1]: https://i.stack.imgur.com/E5IDW.png
The electrolyte solutions used here are $\ce{ZnSO4(... |
In a recent inorganic chemistry lab session, we tested the pH of various ions in water. The water turned out to be on the acidic side (5.5 with pH-paper, **5.59** with pH-meter). A solution of $Mg^{2+}$ gave some strange results. The pH kept rising when using a pH-meter, going from around 4.2 to **5.83** (higher than t... |
pH of an aqueous solution of Mg2+ kept rising above that of clean water. What's going on? |
The carcass was a projectile weapon developed by the French in the second half of the 17th Century. It was "named [carcass][1] because the circles which pass from one ring, or plate, to the other, were thought to resemble the ribs of a human carcass."
[![enter image description here][2]][2]
illustration from the ar... |
What color would be produced by the burning of the listed chemicals of the projectile weapon the carcass? |
In a recent inorganic chemistry lab session, we tested the pH of various ions in water. The water turned out to be on the acidic side (5.5 with $\mathrm{pH}$-paper, **5.59** with $\mathrm{pH}$-meter). A solution of $\ce{Mg^{2+}}$ gave some strange results. The $\mathrm{pH}$ kept rising when using a $\mathrm{pH}$-meter,... |
I need to prepare the $\pu{1M}$ solution of sodium crotonate, however, I don't have one in lab, but I do have sodium hydroxide and crotonic acid.
Thus, I calculated that for $\pu{100 mL}$ of $\pu{1M}$ solution I need: ~$\pu{4g}$ of $\ce{NaOH}$ and ~$\pu{8.6g}$ of crotonic acid. After preparation of solution (approx... |
Hydrogen and hydroxide both exceed sodium and chlorine in terms of reduction and oxidation potential respectively.
While electrolyzing a concentrated solution of aqueous NaCl, it is known that chlorine is discharged at the anode (contaminated with traces of oxygen). However, at the cathode, hydrogen is charged in p... |
I was looking through mass spectrums of haloalkanes and found the one for 1,2-dibromobutane confusing:
[![mass spectrum dibromobutane][1]][1]
The base peak is at 55 m/z, and the only fragment I can think of with that ration will be $\ce{C4H7+}$. The two bromine atoms must be absent as the relative molecular mass of... |
Why do dihaloalkanes lose both halogen atoms during mass spectrometry? |
These numerical values have been determined by mass spectrometry.
In brief, it starts form a box like a match box in the vacuum. No air in the room around the box. There are many plates and tubes in this box. First a small tube is introduced for delivering some hydrogen gas in the box. Second two thin metallic poin... |
While studying ionic equilibrium, I came across a term "Isohydric Solutions" which is defined as
>Solutions of electrolyte are said to be isohydric if the concentration of the common ion present in them is the same and on mixing such solutions, there occurs no change in the degree of dissociation of either of the ele... |
what does isohydric solution mean? |
### What is the endo-selectivity of Diels-Alder reactions? ###
If the diene used in the Diels-Alder reaction has asymmetric substituents at the end carbons, and if the dienophile is unsymmetric, then two different isomers of the final adduct can form. The isomer, where the functional group(s) (usually carbonyl) on t... |
I need to prepare the $\pu{1M}$ solution of sodium crotonate, however, I don't have one in lab, but I do have sodium hydroxide and crotonic acid.
Thus, I calculated that for $\pu{100 mL}$ of $\pu{1M}$ solution I need: ~$\pu{4g}$ of $\ce{NaOH}$ and ~$\pu{8.6g}$ of crotonic acid. After preparation of solution (approx... |
I need to prepare the $\pu{1M}$ solution of sodium crotonate, however, I don't have one in lab, but I do have sodium hydroxide and crotonic acid.
Thus, I calculated that for $\pu{100 mL}$ of $\pu{1M}$ solution I need: ~$\pu{4g}$ of $\ce{NaOH}$ and ~$\pu{8.6g}$ of crotonic acid. After preparation of solution (approx... |
Are the height of the Cubic Close packing Lattice and the Hexagonal Close Packing the same?
My understanding says that these unit cells are formed by different arrangement of atoms, ABC for CCP and ABAB for HCP and because they are made from two different layers their heights should be different, is it so? And if it i... |
Are the height of the Cubic Close packing Lattice and the cubic Hexagonal Close Packing the same?
My understanding says that these unit cells are formed by different arrangement of atoms, ABC for CCP and ABAB for HCP and because they are made from two different layers their heights should be different, is it so? And i... |
I need to prepare the $\pu{1M}$ solution of sodium crotonate, however, I don't have one in lab, but I do have sodium hydroxide and crotonic acid.
Thus, I calculated that for $\pu{100 mL}$ of $\pu{1M}$ solution I need: ~$\pu{4g}$ of $\ce{NaOH}$ and ~$\pu{8.6g}$ of crotonic acid. After preparation of solution (approx... |
You need to add two quantum numbers for the electron: s and ms to take in account its Fermionic nature.
The concept of quantum number is quite general and can be applied both to monoelectronic wavefunctions both poliectronic ones. Given a physical system, a quantum number is an integer or a semi integer associated ... |
I read that silver in the presence of hydrogen sulfide corrodes to form silver sulfide and hydrogen.
$$\ce{Ag + H2S -> AgS + H2}$$
But in the reactivity series silver is placed much below hydrogen.
So, how is this displacement reaction taking place at all?
Reference:
_J. Chem. Educ._ 2000, 77, 3, 328A; [d... |
Wondering for both strong and weak acids. Is it 10 dilutions for both (as the pH log scale suggests? |
How can you increase the pH of any acid by 1? |
In order to increase the pH of a solution of some acid $\ce{HA}$ by 1, how many times must it be diluted by? The pH log scale suggests that the required dilution factor is 10. Is that generally valid for strong and/or weak acids, or do we need to take into account the dissociation constant for weak acids? |
How can you increase the pH of an acidic solution by 1? |
By far, my understanding is that a molecule is made up of atoms bonded together. For example, a molecule of water $ H_{2}O $ has 2 hydrogen atoms and one oxygen atom.
However, when it comes to Avogadro's number, I'm getting confused because it mixes the concept and treat it like is the same
> Avogadro's number is... |
Atoms vs molecule when talking about the avogadro's number? |
According to the referenced paper, VR has an AChE inhibition reaction rate constant almost 4 times that of VX. Interestingly, its reaction rate constant for aging of the enzyme is less than that of VX, despite the fact that, as acknowledged by the authors of the paper, aging tends to occur faster when the leaving group... |
### What is the endo-selectivity of Diels-Alder reactions? ###
If the diene used in the Diels-Alder reaction has asymmetric substituents at the end carbons, and if the dienophile is unsymmetric, then two different isomers of the final adduct can form. The isomer, where the functional group(s) (usually carbonyl) on t... |
The carcass was a projectile weapon developed by the French in the second half of the 17th Century. It was "named [carcass][1] because the circles which pass from one ring, or plate, to the other, were thought to resemble the ribs of a human carcass."
[![enter image description here][2]][2]
illustration from the ar... |
### What is the endo-selectivity of Diels-Alder reactions? ###
If the diene used in the Diels-Alder reaction has asymmetric substituents at the end carbons, and if the dienophile is unsymmetric, then two different isomers of the final adduct can form. The isomer, where the functional group(s) (usually carbonyl) on t... |
I am attempting to research the results of case studies regarding polytetrafluoroethylene [PTFE] (commercially known as Teflon). More specifically I am attempting to make sense of [this Abstract on Acute pulmonary effects of ultrafine particles in rats and mice][1]. Not being a chemist I'm having a hard time understand... |
In my school text book there is a passage that says:
> The presence of reactants in thermos flask or any other closed insulated vessel is an example of an *isolated system*.
Then a few passages of text later it says:
> we take a system containing some quantity of water in a thermos flask or in an insulated b... |
What is the difference between an Adiabatic System and an Isolated System? |
I think the authors' choice of words might have confused you a bit.
>We found that neither the ultrafine Teflon particles alone when generated in argon nor the Teflon fume gas-phase constituents when generated in air were toxic after 25 minutes of exposure.
What the authors mean is that when they used only *ultr... |
I am asked to predict the correct molecular geometry of $\ce{BaH2}$ according to VSEPR theory.
I assumed that it is linear due to barium being an alkaline earth metal and therefore not having any lone pairs when bonded to two hydrogen atoms, but apparently the bond angle between the two hydrogen atoms is about 119°.
... |
There are quite a few approaches (ranging from empirical additive rules based on presence of functional groups to full blown *in silico* QM calculations) to predicting molecular properties such as UVmax absorption or IR vibrational frequencies. While not perfect, they give a general ballpark range of what to look f... |
By far, my understanding is that a molecule is made up of atoms bonded together. For example, a molecule of water ($\ce{H2O}$) has 2 hydrogen atoms and one oxygen atom.
However, when it comes to Avogadro's number, I'm getting confused because it mixes the concept and treats it like it is the same.
> Avogadro's nu... |
While studying ionic equilibrium, I came across the term "Isohydric Solutions" which is defined as:
>"Solutions of electrolyte are said to be isohydric if the concentration of the common ion present in them is the same and on mixing such solutions, there occurs no change in the degree of dissociation of either of the... |
What does isohydric solution mean? |
While studying ionic equilibrium, I came across the term "Isohydric Solutions" which is defined as:
> Solutions of electrolyte are said to be isohydric if the concentration of the common ion present in them is the same and on mixing such solutions, there occurs no change in the degree of dissociation of either of the... |
Can we balance a redox reaction in basic medium just like as acidic medium and add OH- ions on both sides to cancel out H+ Ions? |
We have electric conductivity in metal because the regularity and interaction in a crystal allow for the creation of conduction bands. We should not find these bands in mercury so how could liquid mercury be an conductor? How can we describe the electrical conductivty of mercury. |
Why is liquid mercury conductive if you do not have the lattice periodicity to describe the collective behavior of conducting electrons? |
I took this molfile of benzoic acid:
```
ACD/Labs0708041726
9 9 0 0 0 0 0 0 0 0 1 V2000
13.2076 -5.2994 0.0000 C 0 0 0 0 0 0 0 0 0 0 0 0
14.3539 -4.6250 0.0000 C 0 0 0 0 0 0 0 0 0 0 0 0
13.2076 -6.6480 0.0000 C 0 0 0 0 0 0 0 0 0 0 0... |
Addition of 1 equivalent bromine to 1,3 pentadiene at temperature below 0 degree Celsius gives which compound? |
### What is the endo-selectivity of Diels-Alder reactions? ###
If the diene used in the Diels-Alder reaction has asymmetric substituents at the end carbons, and if the dienophile is unsymmetric, then two different isomers of the final adduct can form. The isomer, where the functional group(s) (usually carbonyl) on t... |
We used these to analyze the stability of molecules in an Organic Chemistry Course.
My teacher analyses the stability of compounds on 3 levels:
1. Atom level by studying the hybridization of the main atom
2. Secondary Orbital Interactions: he first draws a good resonance structure, he identifies candidates that pa... |
What are "Secondary Orbital Interactions" in Organic Chemistry? |
Curing and preventing silicon caulk from sticking to itself
[Food Grade RTV Silicone Sealant Adhesive Clear 10.3oz][1] when creating tubes.
Some videos show using hot water and some videos show using cold water and hydrogen peroxide [Video link on using silicone to create tubes][2]. Anyone know of a **more exact f... |
You can't find this entry in CCDC's CSD, because the scope of this database are small _organic_, or _organometallic_ molecules' crystal structures. (For large organic molecules, analogue studies' data may be found, e.g., on [wwpdb.org][1].) Because your compound is considered as _inorganic_*, you'll find it in the IC... |
I've synthesised a protic and deuterated version of a specific molecule where there are two deuterium atoms in the latter. I then go about and measure the kinetic isotope effect (KIE) for a reaction involving these two molecules. However, in many papers where there are multiple deuteriums per molecule it is common to q... |
Curing and preventing silicon caulk from sticking to itself
[Food Grade RTV Silicone Sealant Adhesive Clear 10.3oz][1] when creating tubes.
Some videos show using hot water and some videos show using cold water and hydrogen peroxide [Video link on using silicone to create tubes][2]. Anyone know of a **more exact f... |
When hf ≥ work function, Then the electron still comes out. So, if I say kinetic energy of ejected electron = 0, it should still come out.
Then, how does the electron even move out or gets ejected if its $v=0$? |
I want to understand what are the particles of a colloid in the microscopic scale. According to [Wikipedia][1]:
> A colloid is a phase separated mixture in which one substance of
> microscopically dispersed insoluble or soluble particles is suspended
> throughout another substance.
What I can't understand is ... |
Are the particles of a colloid "solid"? |
I was trying to understand the derivation of the formula $G = G^\circ + RT \ln (P/P^\circ)$ starting with the following relationships:
$$
dU = TdS - PdV \\
dH = dU + PdV + VdP = TdS + VdP \\
dG = dH - TdS - SdT = VdP - SdT
$$
Under isothermal condition, $dG = VdP$ ($dT = 0$). Therefore the change in $G$ from ... |
What would be the physical interpretation of the equation dG = VdP - SdT? |
I was trying to understand the derivation of the formula $G = G^\circ + RT \ln (P/P^\circ)$ starting with the following relationships:
$$
dU = TdS - PdV \\
dH = dU + PdV + VdP = TdS + VdP \\
dG = dH - TdS - SdT = VdP - SdT
$$
Under isothermal condition, $dG = VdP$ ($dT = 0$). Therefore the change in $G$ from ... |
I read somewhere that this happens because of better shielding of outer s electrons due to completely filled d orbitals of zinc, but I didn't understand it.
Since Zn has an electronic configuration of [Ar]4s² 3d¹⁰
And Cu has [Ar] 4s¹ 3d¹⁰
Both are having completely filled d orbitals so both of them should be havin... |
Why is zinc electrode at a higher potential than copper electrode in a galvanic cell? |
> If I want to increase the voltage, which electrolyte do I change?
Hope you are familiar with the term *electrolyte* which is the solution where ions flow in the electrochemical cell
[![Galvanic Cell][1]][1]
[1]: https://i.stack.imgur.com/E5IDW.png
The electrolyte solutions used here are $\ce{ZnSO4(... |
PIDA ((Diacetoxyiodo)benzene) is a hypervalent iodine(III) compound that acts an attractive oxidizing agent in most of the transition metal catalyzed reactions. Can someone explain me the mechanism of PIDA in the hydroxilation of C-H bonds? |
> If I want to increase the voltage, which electrolyte do I change?
Hope you are familiar with the term *electrolyte* which is the solution where ions flow in the electrochemical cell
[![Galvanic Cell][1]][1]
[1]: https://i.stack.imgur.com/E5IDW.png
The electrolyte solutions used here are $\ce{ZnSO4(... |
What is the net direction of dipole moment in $\ce{F2O}$ molecule?
In the case of $\ce{NH3}$ and $\ce{NF3}$ molecules both have net dipole moment with direction reversed due to strong electronegativity of fluorine atoms, whereas in the case of $\ce{H2O}$ the direction of net dipole moment is from oxygen atom towards... |
Is seven a hard theoretical limit (there *can’t* be an eighth period) or is it there just because we haven’t discovered/synthesized anything beyond that? |
Why are there only 7 periods in the periodic table? |
There is no *theoretical* limit to the number of rows, but...
* On one hand, as Tom Lehrer states, [there may be many others but they haven't been discovard][1].
* On the other hand, after all [S, P, D and F orbitals][2] are filled in the seventh period, there *might* be a new row, or there might be an *extension* ... |
Is 1 ethyl 2 methyl oxirane optically active? |
I was trying to understand the derivation of the formula $G = G^\circ + RT\ln (p/p^\circ)$ starting with the following relationships:
$$
\begin{align}
\mathrm dU &= T\,\mathrm dS - p\,\mathrm dV \tag{1}\\
\mathrm dH &= \mathrm dU + p\,\mathrm dV + V\,\mathrm dP = T\,\mathrm dS + V\,\mathrm dp \tag{2}\\
\mathrm d... |
What would be the physical interpretation of the equation dG = VdP − SdT? |
I was trying to understand the derivation of the formula $G=G^\circ+RT\ln (p/p^\circ)$ starting with the following relationships:
$$
\begin{align}
\mathrm dU&=T\,\mathrm dS-p\,\mathrm dV\tag{1}\\
\mathrm dH&=\mathrm dU+p\,\mathrm dV+V\,\mathrm dp=T\,\mathrm dS+V\,\mathrm dp\tag{2}\\
\mathrm dG&=\mathrm dH-T\,\ma... |
What would be the physical interpretation of the equation dG = Vdp − SdT? |
Why is the methyl radical planar? The VSEPR theory would predict an angle between 120° and 109.5°, while it is actually 120°. |
Is 2 ethyl 3 methyl oxirane optically active? |
Now , In some textbook I have read that orbital is nothing but the shape of electron . s,p,d orbitals etc.
So , after knowing shape of an orbital . I got to know that inside the orbital is an electron and there is a probability of electron to be present in it at specific positions( So , please confirm me if we talk a... |
Now , In some textbook I have read that orbital is nothing but the shape of electron . s,p,d orbitals etc.
So , after knowing shape of an orbital . I got to know that inside the orbital is an electron and there is a probability of electron to be present in it at specific positions( So , please confirm me if we talk a... |
Now , In some textbook I have read that orbital is nothing but the shape of electron . s,p,d orbitals etc.
So , after knowing shape of an orbital . I got to know that inside the orbital is an electron and there is a probability of electron to be present in it at specific positions( So , please confirm me if we talk a... |
Can whether a given reaction is exothermic or endothermic in nature be determined if only the sign of Gibbs free energy is given? |
Can Gibbs free energy determine whether a reaction is endothermic or exothermic? |
I have a question regarding using household bleach, and wonder if someone knowledgeable can help, please?
I have used household bleach (sodium hypochlorite, sodium hydroxide, coco alkyldimethyl, amines, N-oxides, non-ionic surfactants) to bleach mold that had formed in my bathroom on the tiles. I probably used too m... |
I understand that some decompose under heat.
Some will form a different product, Such as CuSO4 becoming CuO if heated too much and we wouldn't recover all of the water.
Some, such as AlCl3 actually forms HCl instead of water and needs to be reacted with another compound first.
But what other reasons are there,... |
When we place metal electrode in solution of its ions, metal ions from metal have tendency to go into solution and ions from solution tend to enter the metal lattice. My question is what is a cause of this tendency for ions in metal lattice? Is it the same tendency which creates vapor pressure of liquids a.k.a Boltzman... |
Why Do Electrodes Develop Equilibrium Potential? |
Some element isotopes have half-lives that are as short as a couple minutes to an hour. Does that mean you can watch it (or catch it on video) turn into 2 different elements? What would something like that look like? |
What does radioactive decay look like? |
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