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How can I compare the leaving group ability of $Br^+$ and $Cl^+$ ions for the electrophilic substitution reactions for aromatic compounds? |
Has anybody synthesized di- or higher nitrated cyclopentadienes possibly with methyl or other groups in the 1 position (analogs of TNT)? |
I was wondering if two solids can form from two aquas solutions?
Any examples? |
Can two percipates form in a percipatation reaction that starts with only two molecules? |
I was wondering if two solids can form from two aqueous solutions?
Any examples? |
Can two precipitates form in a precipitation reaction that starts with only two molecules? |
Absorption of a photon typically results in a vibrationally excited higher electronic state of the same multiplicity.
$$\ce{S_0 ->[h\nu_{ex}]S_1}$$
In most cases, the excited state deactivates through **internal conversion** in a radiationless process via vibrational energy exchange with solvent molecules. No li... |
Why is arsenous acid denoted $H_3AsO_3$? |
Why is arsenous acid denoted H_3AsO_3? |
Without appealing to reactions that require photons / light, how do chemists achieve very high concentration of continually produced, though quite short lived, singlet oxygen (i.e. $^1O_2$ where dioxygen is typically in the triplet $^3O_2$ state) in aqueous solution? I suppose I'll also ask the same question if we hav... |
How do I create a concentrated solution of singlet oxygen (in the dark)? |
Without appealing to reactions that require photons / light, how do chemists achieve a very high concentration of continually produced, though quite short lived, singlet oxygen in aqueous solution (i.e. $^1O_2$ where dioxygen is typically in the triplet $^3O_2$ state)? I suppose I'll also ask the same question if we h... |
what is the (conceptual) difference between binding energy and adsorption energy? |
Without appealing to reactions that require photons / light, how do chemists achieve a very high concentration of continually produced, though quite short lived, singlet oxygen in aqueous solution (i.e. $^1O_2$ where dioxygen is typically in the triplet $^3O_2$ state)? I suppose I'll also ask the same question if we h... |
Without appealing to reactions that require photons / light, how do chemists achieve a very high concentration of continually produced, though quite short lived, singlet oxygen in aqueous solution (i.e. $^1O_2$ where dioxygen is typically in the triplet $^3O_2$ state)? I suppose I'll also ask the same question if we h... |
Does isotretinoin affects contraception hormonal pills - Ethinylestradiolum, Drospirenonum? Asking as a pharmacologist not a patient. |
Two vessels of the same volume, in the
same location and open to the atmosphere. One is of a small diameter, the
other is of a larger diameter.
The question is will the vessel with the
larger surface area evaporate the liquid
faster than the smaller one?
$If not!$I need answer to other question ,if i am not wron... |
Does rate of Evaporation change with surface area? |
> What are the steps in calculating the photosynthetic rate (umole O2 /
> m2 / min) for a leaf that with an area of 0.0025 m2 and a O2 evolution
> rate of 0.096 %O2 / min?
To do so , the first step is to convert it to uL i.e. 960uL O2/min.
The second step should be to convert it to umoles. So, how do we do that... |
How could one determine the likelihood of one cation displacing another on a negatively charged exchange site of a clay particle?
For example, in a soil solution containing equal parts (by number of atoms) $\ce{Ca^{2+} , Mg^{2+}, K+, Na+, Al^{+3}}$ which cations will find the most exchange sites and which will ultim... |
What is a good and free software for this endeavor? Any recommended articles on the subject?
I want to design dft functionals, trying out different parametrizations and optimizing mixing constants for exchange and correlation contributions for specific data sets. Even add PT2 perturbation energy into the mix if possib... |
Defining and testing custom made DFT functionals? |
Actually, it does.
Normally, though, you won't notice it as it will be heavily diluted by the nitrogen and won't ever reach a concentration large enough to worry about. It's different if you pull air through a trap as the oxygen content of the flowing gas will be condensed preferentially leaving a liquid that is con... |
From my perspective these resonance structures allow these specific polyatomic ions to act as Donor-Acceptor molecules. Many donor-acceptor molecules also tend to be Conjugated systems because they have chains of alternating conjugated pi orbitals.
So does this imply that these ions (due to their resonance structur... |
Can polyatomic ions (CO3,PO4,SO4,NO3) be considered conjugated systems? |
Without appealing to reactions that require photons / light, how do chemists achieve a very high concentration of continually produced, though quite short lived, singlet oxygen in aqueous solution (i.e. $^1O_2$ where dioxygen is typically in the triplet $^3O_2$ state)? I suppose I'll also ask the same question if we h... |
Since you mentioned "free", you maybe want to have a look at [GAMESS][1] from the Gordon group.
I have really no idea whether it's fit for the task, but last time I checked it was free for academic use.
<hr>
There's of course [Turbomole][2], but according to an [old thread in a forum][3] from 2007, they weren... |
Without appealing to reactions that require photons / light, how do chemists achieve a very high concentration of continually produced, though quite short lived, singlet oxygen in aqueous solution (i.e. $^1O_2$ where dioxygen is typically in the triplet $^3O_2$ state)? I suppose I'll also ask the same question if we h... |
Without appealing to reactions that require photons / light, how do chemists achieve a very high concentration of continually produced, though quite short lived, singlet oxygen in aqueous solution (i.e. $^1O_2$ where dioxygen is typically in the triplet $^3O_2$ state)? I suppose I'll also ask the same question if we h... |
"Conjugated" implies a 1,3-shift to move an electron or hole. It is a remnant of LCAO modeling that is obviously wrong but fantastically useful short of the Woodward-Hoffmann rules. I'm not sure inorganikers would like the name as such. MO modeling is accurate but unwieldly. "Delocalized" or "resonance hybrid" is go... |
How can you make an unfavorable reaction go backwards?
From my understanding if we wanted a reaction at equilibrium to go backwards (i.e. form reactants from products), we would add more product into the solution.
But I'm not sure how the reaction being an unfavorable one changes the above statement.
After mak... |
Look up the industrial process. Organic essences are usually steam distilled or pot-to-pot durped, or liquid CO2 or liquidn propane/butane extracted. We're not making hash oil, are we?
http://www.fao.org/inpho_archive/content/documents/vlibrary/ad420e/img/AD420e26.gif
http://www.seanmichaelragan.com/img/radial_a... |
Correct me If I am wrong, given a reaction at equilibrium, if we say add more concentration of products to the reaction, the rate going backwards would increase to try to get back to equilibrium.
I was wondering if the rate forward stays the same or slows down?
|
I live in the tropics, and have a water tank that sits in the sun, forming algae. Every year, I need to scrub the thing out. The plumber I've hired for the job wants to flush my water pipes with HCl to kill any residual algae. Should I let him? If not, why not? |
Does HCL kill algae? |
> home-made handwash (liquid soap) consists of bar soap, water, Epsom
> salts, and coconut oil.
Bar soap - OK. Might be sodium or potassium fatty acid carboxlates, or syndet.
Epson salts - not OK. Bivalent cations turn literal soap into insoluble slime. Synets don't much like it either.
Coconut oil - not OK. ... |
Are they metal pipes? If you want to kill algae as such, flush with a diluted quaternary ammononium disinfectant, let sit a day, then flush everything very well indeed, and again. If you have rubber or polymer fittings, don't do that, either, for the stuff diffuses in.
|
bassa makes iron rusted? |
Can two precipitates form in a precipitation reaction that starts with only two compounds in water? |
I live in the tropics, and have a water tank that sits in the sun, forming algae. Every year, I need to scrub the thing out. The plumber I've hired for the job wants to flush my water pipes with HCl to kill any residual algae. The pipes are mostly PVC, with braided metal hose and metal fittings here and there. Should I... |
If I have an intermetallic and want to know the specific arrangement of atoms in the lattice, how can I determine that? What I mean is the Cartesian (xyz) position, or the (abc) positions in the lattice. In my case, I am working with Ni3Sn4, which has a space group C2/m. The space group diagram can be found at <http://... |
How does a space group determine crystal structure? |
If I have an intermetallic and want to know the specific arrangement of atoms in the lattice, how can I determine that? What I mean is the Cartesian (xyz) position, or the (abc) positions in the lattice. In my case, I am working with Ni3Sn4, which has a space group C2/m. The space group diagram can be found [here][1].
... |
> What are the steps in calculating the photosynthetic rate ($\mu\text{mole}\ce{O2}/$
> $\text{m}^2 / \text{min}$) for a leaf that has an area of $0.0025 \text{m}^2$ and a $\ce{O2}$ evolution
> rate of $0.096$% $\ce{O2}/\text{min}$?
To do so , the first step is to convert it to $\mu L$ i.e. $960 \mu L\text{ }\ce{O... |
How does titanium occur in nature?
Is it available as a native metal or only in the form of ores?
Which precesses are typically used to convert the natural resources to the solid metal?
Any hints on where to find further information are welcome. Thank you very much in advance. |
How is titanium metal obtained from natural resources? |
This question has been intriguing me since 10th or 11th grade. The teacher just told us about it but didn't get into the details of the why. Recently I asked a biochemist but couldn't get an answer. So I bring it here.
CH3OH + O2 -> CO2 + H2O
is the complete combustion equation of methanol. But the problem is it ... |
What is the implication of not being able to balance the complete combustion reaction equation of methanol? |
The question sounds vague and non-specific because my background in chemistry is limited to undergrad college courses. However, I am interested in learning the correlations between the atom-by-atom structure of molecules (simple, complex...) and the resultant physical properties thereof.
So far, it seems most the m... |
How does molecular structure affect physical properties? |
This question has been intriguing me since 10th or 11th grade. The teacher just told us about it but didn't get into the details of the why. Recently I asked a biochemist but couldn't get an answer. So I bring it here.
$$\ce{CH3OH + O2 -> CO2 + H2O}$$
is the complete combustion equation of methanol. But the probl... |
The reduction of water at a cathode is represented by the following equation:
Cathode (reduction): 2 H2O(l) + 2e− → H2(g) + 2 OH-(aq)
If this is done in a divided cell, what would happen to the OH- anions? The hydrogen gas would accumulate and bubble would. Would the OH- anions just build up in the solution? Do t... |
What happens to the hydroxide anion during the electroreduction of water? |
To build lattice you need the space group, the three unit cell dimensions, the three unit cell angles, each atom's fractional coordinates (e.g., a *.cif file overall),
Acta Cryst. B38, 598 (1982) doi:10.1107/S056774088200346X
Ni3Sn4, C2/m, a=12.214, b=4.060, c=5.219 A, beta=105.0 degrees (others 90 degrees by defa... |
The reduction of water at a cathode is represented by the following equation:
Cathode (reduction): $\ce{2 H2O_{(l)} + 2e^{−} → H2_{(g)} + 2 OH^{-}_{(aq)}}$
If this is done in a divided cell, what would happen to the $\ce{OH-}$ anions? The hydrogen gas would accumulate and bubble would form. Would the OH- anions j... |
The reduction of water at a cathode is represented by the following equation:
Cathode (reduction): $\ce{2 H2O_{(l)} + 2e^{−} → H2_{(g)} + 2 OH^{-}_{(aq)}}$
If this is done in a divided cell, what would happen to the $\ce{OH-}$ anions? The hydrogen gas would accumulate and bubble would form. Would the $\ce{OH-}$ a... |
How does iron rust in basic conditions? |
Looking at avidity between a ligand-receptor, you're looking at an enhancement of the $K_d$ compared to a lone ligand.
**Is it more appropriate to compare the $K_d$ using the concentration of the "free" ligand or the concentration of the free complex?**
Using the ligand is odd at the lower regimes since the lig... |
Any references for adsorption of ions to metal surfaces? |
Calculate the heat produced when a strip of Mg metal with a mass of 0.0801 gram is reacted with 50.0ml of 1.0M HCL to raise the temperature of water to 7.6C (change in temp.=7.6C). Calculate the heat produced when a mole of this metal is used.
I have this so far q= m x c x change in temp
m=0.0801gram
change in t... |
If a plastic is marked PP as in Polypropylene (i.e. resin code 5)
http://en.wikipedia.org/wiki/Resin_identification_code
Is it automatically safe for steaming and microwaving, such that it wouldn't leach chemicals into the food(besides not melting)?
|
Are all PP(Polypropylene), i.e. resin code 5 plastics, safe for microwave and steaming? |
It can help to imagine the experimental setup.
Imagine a thermally insulated reaction container, let's call it *calorimeter*, that is filled with 50 ml 1 M $\ce{HCl}$ ( = a solution of hydrogen chloride gas in **water**).
We have to measure a temperature change ($\Delta{} T$), that comes from an exothermic reacti... |
Calculate the heat produced when a strip of $\ce{Mg}$ metal with a mass of $0.0801$ gram is reacted with $50.0$ml of $1.0M$ $\ce{HCl}$ to raise the temperature of water to $7.6^\circ C$ (change in temp.=$7.6^\circ C$). Calculate the heat produced when a mole of this metal is used.
I have this so far $q= m \times c \... |
Why is the maximum % for a gold alloy 92%? |
Why molecules of a body exhibit vibrational motion ? Is it due to interaction between various molecules of the body or inter atomic interaction of the same molecule? If it is because of any of them how can these interaction cause the molecules to vibrate. Please explain. |
Is there any chance that you can use a [Teclu][1] or a [Bunsen][2] burner?
If so, you will need a batch of magnesia ($\ce{MgO}$) sticks too.
Most of the cations can be identified by a **flame test**, since they furnish a typical colour in the "blue" flame of the burners.
- Na: intense yellow
- K: lilac/viol... |
Consider the following reaction : $\ce{H2 + Cl2 -> 2HCl}$
A) If you have 15.00 liters of hydrogen reacting with 10.00 liters of chlorine at STP, how many liters of HCl would you produce?
B) What would be the limiting reagent?
C) How many moles of excess reagent would remain?
Please explain.
-------------... |
I heard there is a standard about cleaned glass, namely
>Chemically clean glass supports a uniform film of water, with no hanging droplets visible.
I tried to clean my dishes at home using detergent. After several efforts, the ceramics-made dish looks like a uniform film of water just after finishing the cleaning... |
How to achieve clean dish and glass? |
I heard there is a standard about cleaned glass, namely
>Chemically clean glass supports a uniform film of water, with no hanging droplets visible.
I tried to clean my dishes at home using detergent. After several efforts, the ceramics-made dish looks like a uniform film of water just after finishing the cleaning... |
I am not that familiar with cleaning procedures, but the 'rule' to support a uniform film of water without droplets seems to be an easy proxy for checking whether there are still contaminated spots on the surface. In that case, a phenomenon called [contact line pinning][1] will occur, which results in droplets. The uni... |
Your title and question are a bit different.
>Is crushing an avocado a chemical or physical change?
Physical. Crushing (or any other physical manipulation of) any substance is, by definition, a physical change. However, those physical changes can affect the conditions for a chemical change, potentially causing a... |
There are several laboratory techniques to rigorously clean glass. Here are a few of the more common ones, to add to the other answers. There are probably more procedures, and it's also common to perform more than one treatment to maximize efficiency.
Practically none of these have any use at home, because they are... |
My book mentioned that the energy barrier for cyclohexane to reach the half-chair conformation is 50.6 $\text{kJ mol}^{-1}$. It says that from this value, it was calculated that cyclohexane undergoes $10^5$ flips per second.
How did they calculate this? We can assume that all the conformational states possible will ... |
How to calculate the frequency of cyclohexane conformational interconversion? |
I heard that there is a standard about cleaned glass, namely
>Chemically clean glass supports a uniform film of water, with no hanging droplets visible.
I tried to clean my dishes at home using detergent. After several efforts, the ceramic-made dish looks like a uniform film of water just after finishing the clea... |
How to achieve clean dishes and glasses? |
Two vessels of the same volume, in the
same location and open to the atmosphere. One is of a small diameter, the
other is of a larger diameter.
The question is will the vessel with the
larger surface area evaporate the liquid
faster than the smaller one?
**If not!** I need answer to other question ,if i am not w... |
![In the image you can see two resonating structures they are nitric oxide structures.][1]
[1]: https://i.stack.imgur.com/9MMAe.png
In the first resonating structure you can see 5 unpaired electrons and 4 shared electrons on nitrogen, then isn't this a extended octet? If it is so, then in which orbital that 9... |
Where does the 9th electron go? |
Is there a fixed ratio that can be used to calculate the number of neutrons in the nucleus of the most stable isotope of an element by knowing the atomic number?
Side question: if Z is the symbol for atomic number, are there symbols for the number of neutrons and/or atomic mass? |
![In the image you can see two resonating structures they are nitric oxide structures.][1]
In the first resonating structure you can see 5 unpaired electrons and 4 shared electrons on nitrogen, then isn't this a extended octet? If it is so, then in which orbital that 9th electron is revolving?
In the second resonat... |
Where does the 9th electron go in a $\ce{N=O}$ bond? |
Nitric oxide is a tough molecule to represent as a Lewis structure. However, you have made one common mistake in your structures. I also want to clear up a misconception about resonance that's present in your post. Finally, I will need to introduce a difference bonding picture of $\ce{NO}$ to answer your question about... |
I will not ask why you would want to do that.
You're right that the benzylic alkohol can be deprotonated. But that won't help you for the intended reaction.
Regarding the possible mechanisms, I suggest to do it on paper.
Draw the starting material and split the bonds. Draw the fragments that result from spli... |
Would molecules like C<sub>2</sub>, H<sub>2</sub>, etc., be considered 1 mole of diatomic [element] or 2 moles of [element]? |
Would 2 C2 be 2 moles of diatomic carbon, or 4 moles of carbon? |
If the longest carbon chain is symmetric numbering-wise (meaning the numbering schemes are identical both ways) and has all alkyl substituents, should one prioritize the largest alkyl group?
Thanks in advance. |
Would molecules like H<sub>2</sub> be considered 1 mole of diatomic [element] or 2 moles of [element]? |
Would 2 H2 be 2 moles of diatomic carbon, or 4 moles of carbon? |
I was comparing boiling points of $CHCl_3$ and $CH_3Cl$. According to me B.P. of $CHCl_3$ should be higher due to it's higher molecular mass than $CH_3Cl$, but the answer is opposite ,ie. B.P. of $CH_3Cl$ $\gt$ B.P. of $CHCl_3$.Why? |
> but the answer is opposite ,ie. B.P. of CH3Cl > B.P. of CHCl3.
Really?
$\ce{CH3Cl}$ has a boiling point of **-24** °C. It is a **gas**.
$\ce{CHCl3}$ has a boiling point around 61 °C. |
> but the answer is opposite ,ie. B.P. of CH3Cl > B.P. of CHCl3.
Really?
$\ce{CH3Cl}$ has a boiling point of **-24** °C. It is a **gas**.
$\ce{CHCl3}$ has a boiling point around 61 °C.
<hr>
Edit: **Your argumentation is valid, there was probably just some confusion in the notes.** |
Would molecules like C<sub>2</sub>, H<sub>2</sub>, etc., be considered 1 mole of diatomic [element] or 2 moles of [element]? |
Would 2 C2 be 2 moles of diatomic carbon, or 4 moles of carbon? |
Are you supposed to determine $\Delta_rH$ for the reaction (which is $\Delta_cH$ for the combustion of 2-propanol) or are you supposed to determine $\Delta_fH$ for the formation of 2-propanol?
>If the first case, it might be hard.
The change in internal energy $U$ is equal to the sum of the heat transferred $q$ ... |
> Consider the following reaction
$$\ce{CH3\bond{-}CH\bond{=}CH2 ->T[$\ce{Br2}$/$\ce{NaCl}$]?}$$
What would be the product(s) for this reaction? I am confused because there are two nucleophiles here $\ce{Br-}$ and $\ce{Cl-}$. So, there are two alternatives for the second step. Let me explain what I a... |
Recently I tried to hydrolyze some cellulose : so I added some acid to it (H2SO4) then I noticed nothing. Even after a few days there was no visible change and after doing some tests for glucose, those were negative too. So at the end - expecting nothing would happen - I added some sodium hydroxide (NaOH) to the soluti... |
Molecular mass has NO pertinence to bp, water and ammonia. Look up the bp of perfluorocyclohexane, hexafluorobenzene, and the hydrocarbons. If I want to volatize iron, ferrocene. If I want to volatize iron more, $\ce{Fe(hfac)_3}$ where the ligand is the bidentate enolate anion of 1,1,1,5,5,5-hexafluoro-2,4-pentanedi... |
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