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I understand Le Chatelier's principle and how every change to an equilibrium system causes an opposing reaction from the system. I also understand how, when pressure is increased, the equilibrium shifts to the side with the lowest number of moles of gas and vice versa.
So, why does this happen? How is it more energe... |
Chemical Equilibrium - Why do changes in pressure cause a shift in the ratio of products and reactants? |
If i had an ionic molecule which needed 4 eV to break the ionic bond, a 7 eV photon is shot at it. It is absorbed by the molecule and breaks, where do the rest of the energy goes? |
During the lecture in my chemistry class, my teacher posed the following problem:
> Arrange in terms of increasing vapor pressure:
> a) 0.5m sugar
> b) 0.5m NaCl
> c) 2m ethylene glycol
> d) 2m LiBr
The answer turned out to be: d, c, b, a. However, I do not understand why this is the case. I know the... |
How to arrange substances in order of increasing vapor pressure? |
A lot of the organometallics are rather... interesting compounds to work with. The most famous (among those who care, anyway) is *tert*-butyllithium or t-BuLi. It is the textbook example of a pyrophoric substance, demonstrated to pretty much every chemistry major as an example of an air-sensitive chemical requiring spe... |
Is there any substance that's a 4-4-4 on the NFPA diamond? |
Is there a bifurcation node in the potential energy as a function of reaction progress equation of chemical reactions? |
I originally posted a similar question on math.stackexchange site, but I believe I might have a better chance of having my question answered here after giving it some time.
Anyway, this is my question...
I was thinking about the activation energy of chemical reactions (obviously), and I was wondering if there ex... |
Here are the MOs (more accurately, the breakdown of the MOs) for conjugated hexatriene:
![enter image description here][1]
Now, when first asked to draw the MOs myself, I drew this one for $\psi_3$:
![enter image description here][2]
It still has two nodes, and is still symmetric. I see nothing wrong with... |
Why are these molecular orbital invalid for hexatriene? |
> I originally posted [a similar question on math.stackexchange.com][1], but I believe I might have a better chance of having my question answered here after giving it some time.
I was thinking about the activation energy of chemical reactions, and I was wondering if there exists a bifurcation node somewhere in t... |
Why are these molecular orbitals invalid for hexatriene? |
It's because there's two hydrogen atoms in water, not one. In order to show you, let's assume we're making HO instead of H2O. This would clearly only require half the amount of hydrogen, but still the same amount of oxygen. Thus we have .5 grams of hydrogen combining with 8 grams of oxygen in a 1:1 relationship. Thus t... |
A lot of the organometallics are rather... interesting compounds to work with. The most famous (among those who care, anyway) is *tert*-butyllithium or t-BuLi. It is the textbook example of a pyrophoric substance, demonstrated to pretty much every chemistry major as an example of an air-sensitive chemical requiring spe... |
Can someone help me identify the steps for the following reaction? I'd like to keep track of everything that happens. I can't figure out what happens with oxidation in this context, and thus can't get started.
It's 2-methylpropan-1-ol oxidized with potassium dichromate(VI) in aqueous sulphuric acid to yield 2-methyl... |
I ran an IR spectrum (KBr pellet) and found a sharp absorbance at $2360 \text{cm}^{-1}$, which was unexpected. As far as I can tell, this indicates either a nitrile or $\ce{CO2}$.
I know that there is no nitrile in my product. Would you expect atmospheric $\ce{CO2}$ to show up to a noticeable degree in a typical IR ... |
How much CO2 should one expect in an IR spectrum? |
> I originally posted [a similar question on math.stackexchange.com][1], but I believe I might have a better chance of having my question answered here after giving it some time.
I was thinking about the activation energy of chemical reactions, and I was wondering if there exists a bifurcation node somewhere in t... |
I ran an IR spectrum ($\ce{KBr}$ pellet) and found a sharp absorbance at $2360 \text{cm}^{-1}$, which was unexpected. As far as I can tell, this indicates either a nitrile or $\ce{CO2}$.
I know that there is no nitrile in my product. Would you expect atmospheric $\ce{CO2}$ to show up to a noticeable degree in a typi... |
How much CO₂ should one expect in an IR spectrum? |
I am currently in the process of connecting transition state (TS) structures to other minima in order to determine a reaction pathway. Now I understand the basic concepts of this method. You start with your TS, run an IRC in both the Forward and Reverse directions, then you optimize the final structure in the success... |
Intrinsic Reaction Coordinate - What does 'Connectivity' really mean? |
I am currently in the process of connecting transition state (TS) structures to other minima in order to determine a reaction pathway. Now I understand the basic concepts of this method. You start with your TS, run an IRC in both the Forward and Reverse directions, then you optimize the final structure in the success... |
I'm reading about $\:\mathrm{S_N1}$ and $\:\mathrm{S_N2}$ reaction mechanisms. 1° carbocations are unstable to the point of not having been observed in solution, ever. 2° are more stable, and 3° carbocations are the most stable.
I know that higher stability carbocations do also require less activation energy in thei... |
Why does carbocation stability increase in the order 1°, 2°, 3°? |
I'm reading about $\:\mathrm{S_N1}$ and $\:\mathrm{S_N2}$ reaction mechanisms, and I have a few questions.
My book has a couple of tables, one lists a bunch of substances grouped as good, moderate and poor nucleophiles. Among the good are $\ce{Br-}$ and $\ce{I-}$. So a couple of halogens. I'm figuring chlorine is in... |
How can a group be both a good nucleophile and a good leaving group? |
why aren't aromatic compounds with 3, 4 or 5 carbon atoms taught at high school level chemistry? but we are jumped/taught to 6 carbons aromatics and benzene rings. why?
my core question is: is because it(lower memebers) is tough to understand? |
why not lower aromatic organic compounds? |
Why aren't aromatic compounds with 3, 4 or 5 carbon atoms taught at high school level chemistry? We are instead directly taught about aromatic compounds with 6 carbons/benzene rings. Why?
My core question is: is because the lower members are tough to understand? Do they have any strange properties? |
Why aren't lower aromatic organic compounds taught? |
I’m trying to get a deeper understanding of how mass spectroscopy works. Most tutorials and textbooks I’ve encountered omit certain details about the process and I’m hoping someone out there who understands the process can fill in the gaps. I’ll start by explaining the way I currently understand the process and then li... |
Part of the total reaction is mentioned here:
http://chemistry.about.com/od/demonstrationsexperiments/ht/instantfire.htm
$\ce{2KClO3(s)} + \text{heat} \rightarrow 2\ce{KCl(s)} + 3\ce{O2(g)}$
The rest is a mystery. (And where does the heat come from?)
I regret to say that I have delayed acquisition of organi... |
How does sulfuric acid catalyze the reaction of potassium chlorate and sucrose? |
>Question 1: What’s the difference between an electric field and a magnetic field? And why does the magnetic field bend the ions while the electron field does not. Is this just a consequence of the shape of the apparatus? Could you use a magnetic field to accelerate a particle and a electric field to do the bending? I’... |
Why some people say hydrogen should be above lithium in the periodic table and others argue it should be above fluorine ? Please answer fast since i have a test coming up ...
Thanks a lot !!! |
<sup> I'm not entirely sure of this, comments appreciated</sup>
Leaving group tendency is a thermodynamic variable. So, it depends more on the equilibrium and energies of the reaction. We calculate it from the basicity of the group (weak base -> more stable while solvated -> better leaving group).
Now, iodide i... |
Why do some people say that hydrogen should be above lithium in the periodic table and others argue it should be above fluorine? |
Alfatoxin and benzene are carconogenic, and this is the major concern for low,chronic doses. They are regulated to the few parts per billion level in food. However, according to http://toxnet.nlm.nih.gov/cpdb/pdfs/ChemicalTable.pdf,
aflatoxin is **three to five** orders of magnitude more carcinogenic, as evident from ... |
Alfatoxin and benzene are carconogenic, and this is the major concern for low, chronic doses. They are regulated to the few parts per billion level in food. However, according to http://toxnet.nlm.nih.gov/cpdb/pdfs/ChemicalTable.pdf,
aflatoxin is **three to five** orders of magnitude more carcinogenic, as evident from... |
Please correct me if I’m wrong, but I’ve read that the reason why we use significant figures is to avoid making the result of a calculation more precise than the starting values prior to the calculation. For example, if we were seeking the ratio of two weights, lets call them A and B, using a cheap scale and an expensi... |
Please correct me if I’m wrong, but I’ve read that the reason why we use significant figures is to avoid making the result of a calculation more accurate than the starting values prior to the calculation. For example, if we were seeking the ratio of two weights, lets call them A and B, using a cheap scale and an expens... |
When the electrons that are excited by the energy of burning drop back into lower energy levels they emit light at the wavelength of colour.
When metals are burnt, metal oxides(some coloured) are formed.
When metals are burnt under high temperature, will they turn to plasma state? If so, should the metal ions be ... |
In the reaction of combustion of gunpowder,
"Sulfur is used to speed up the reaction and acts like a catalyst in that it increases the rate of reaction. However, unlike a catalyst, it is used up in the reaction." I understand that transition metals are often used as catalysts but why can sulphur act like a catalyst? |
why can sulphur act like a catalyst? |
I need to control oxygen in a shaken flask in a bioprocess. I need to remove overall oxygen in a shaken flask, and after I need to add oxygen in controlled amounts to a culture in a shaken flask. Someone knows how can I do it?
Thanks for advance.
|
How can I control the oxygen in a shaken flask in a bioprocess? |
I need to control oxygen in a erlenmeyer flask in a bioprocess. I need to remove overall oxygen in a erlenmeyer flask, and after I need to add oxygen in controlled amounts to a culture in a shaken flask. Someone knows how can I do it?
Thanks for advance for your ideas.
|
How can I control the oxygen in an erlenmeyer flask in a bioprocess? |
In the reaction of combustion of gunpowder,
>Sulfur is used to speed up the reaction and acts like a catalyst in that it increases the rate of reaction. However, unlike a catalyst, it is used up in the reaction.
I understand that transition metals are often used as catalysts but why can sulphur act like a catalys... |
Why can sulphur act like a catalyst? |
In organic chemistry, people draw 2p orbitals like this:
i.imgur.com/iC9MOhi.png
(Sorry this is my first question, so I cannot post images. I will fix this when I get my first 10 reputation.)
and then they explain how the orbitals combine to non-bonding (π*) or bonding (π) molecular orbitals, like this:
htt... |
Bonding and anti-bonding orbitals in the light of time-dependent Schrödinger equation? |
In organic chemistry, people draw 2p orbitals like this:
![2p static][1]
and then they explain how the orbitals combine to non-bonding (π*) or bonding (π) molecular orbitals, like this:
![orbitals bonding][2]
depending on whether the orbitals overlap out-of-phase (blue + white) or in-phase (blue + blue, or ... |
I'm currently studying ion exchange resins and generally getting a bit stuck on some points of information which i do not fully understand / are not very well explained within the literature.
I understand that resins having varying selectivity or affinity for a particular ion and selectivity generally increases wit... |
This is part of the reason I really don't like the way we teach significant figures. What's really important isn't the number of digits you have, but rather the uncertainty in your measurements. I think significant figures are taught as an approximation to the proper uncertainty analysis, but it really seems to be not ... |
I'm currently studying ion exchange resins and generally getting a bit stuck on some points of information which I do not fully understand / are not very well explained within the literature.
I understand that resins having varying selectivity or affinity for a particular ion and selectivity generally increases wit... |
I am working on reaction predictions for the AP Chemistry and I need some help with this problem. On a practice quiz I answered with "2Li + O^-2 --> Li2OH". I got zero points for this answer meaning both reactants and products were wrong. What is the correct answer and how would you get to the correct answer? |
What is the product when Lithium solid is dropped in water? |
I am working on reaction predictions for the AP Chemistry and I need some help with this problem. On a practice quiz I answered with $\ce{2Li + O^{2-} -> Li2OH}$. I got zero points for this answer meaning both reactants and products were wrong. What is the correct answer and how would you get to the correct answer? |
I am working on reaction predictions for the AP Chemistry and I need some help with this problem. On a practice quiz I tried to use the rule of "Metal + Water = Metal Oxide" so I answered with $\ce{2Li + O^{2-} -> Li2OH}$. I got zero points for this answer meaning both reactants and products were wrong. What is the cor... |
I do not like body wash always with strong favor. I like hand wash soap to wash my body. Are they differece at all? |
What is the difference between hand wash and body wash soap? |
I am unfortunately not very good at chemistry, so I am having trouble figuring out where to start on this project. I need to have some way of get some amide functional groups stuck on a substrate (most likely some glass beads or slides) so I can try to show some interactions of the amide with a molecule I am intereste... |
![enter image description here][1]
Above are some spectral emission lines for Hydrogen, Helium and Neon.
Using the Schrodinger equation, it's possible to derive the colours that Hydrogen will emit when light is fired at it. A little more complicated (although beyond my rudimentary knowledge of quantum mechanics)... |
Is it possible to work out the colour of *any* molecule? |
Ok, this is a simple problem, but I cant see how to get the answer. I calculated the activity coefficient, $\gamma_\pm$ = 0.389, and I need to find the activity $a_\pm$ for a 0.0120m solution of $Na_3PO_4$.
I know the answer is 0.106 and that $$a_\pm = \frac{m_\pm}{m_0}\gamma_\pm$$
I must be pluggin in the wrong numb... |
I do not like body wash always with strong favor. I like hand wash soap to wash my body. Are they difference at all?
Thanks for the comments, so that I add the following information
I am really sorry that I posted the question using my phone at my office parking lot right before I went to work this morning, so not ... |
I have absorbance values for blood plasma. Absorbance was measured in range of 380 – 600 nm every 5 nm ending up with absorbance values for 45 wave lengths.
I was browsing through literature, and I came across chromacity coordinates (XYZ) and this seems to be a very convenient way of summarizing data about color in ... |
Is it possible to calculate chromacity coordinates using absorbance values? |
Is there a positive radical Aurous, ${Au}^{x+}$? If yes what is the value of x?
We have Auric as ${Au}^{3+}$. |
Is there a positive radical Aurous, ${Au}^{x+}$? |
My textbook states that for most reactions, the reaction rate decreases with time. I wonder what reactions will have increasing reaction rates with time. I know that adding a catalyst will increase the reaction rate but the final reaction rate will finally be zero. So, what reactions will their reaction rates increase ... |
What reactions will their reaction rates increase with time? |
Why doesn't Nitrogen monoxide dimerize even though there is an odd electron present whereas nitrogen dioxide does(which is due to the odd electron on nitrogen)?
thanks in advance! |
Plastic Selection
-
I'm going to have an online machine shop build a part for me using a CAD drawing that I specify.
Typically, these parts are made of Aluminum, but this manufacturer also mills parts out of these plastic materials:
- Polypropylene (PP)
- Polystyrene (PS)
- High impact polystyrene (HIPS)
-... |
How would I select the strongest Plastic Material? |
Why doesn't Nitrogen monoxide dimerize even though there is an odd electron present whereas nitrogen dioxide does (because of the odd electron on nitrogen)?
|
I think the major error you made is applying what you call the "Metal + Water = Metal Oxide" rule. This may apply to *some* metals, but not all. Specifically, Lithium is a Group 1 metal, the so-called Alkali Metals. This means that Group 1 metals tend not to form oxides with water, but rather form *hydroxides* with ... |
Is there an enzyme which is used as a drug (let it be called version $A$) and a mutated version of it ($M$), where the activity of $M$ was found to be higher than $A$?
Any references on such a case would be greatly acknowledged. |
Which mutated enzymes act as better drugs than their non-mutated form? |
So I was wading through several textbooks yesterday reviewing the concepts of buffers. I found them lot more challenging than I used to. One thing in particular disturbed me: The books and internet all said "Yeah, buffers work pretty great in as long as the $pH \approx pK_a\pm 1$." But I am not one to leave these thin... |
Can you create a buffer with a strong acid? |
As we know on fusing two hydrogen atoms we can convert it to helium and breaking them give us two H atom. So why can't we convert mercury to gold by removing 1 proton per atom? |
Why can't we. It will make us pretty rich? |
As we know on fusing two hydrogen atoms we can convert it to helium and by breaking them we get two $\ce{H}$ atoms. So why can't we convert mercury to gold by removing 1 proton per atom? |
Why can't we use fusion to make ourselves rich? |
> Why can't we use fusion to make ourselves rich?
Because at the current stage of technological process making gold from other elements by fusion in large quantities is so costly (energy-wise and therefore money-wise), that it is just extraordinarily unprofitable to do that. |
> Why can't we use fusion to make ourselves rich?
Because at the current stage of technological progress making gold from other elements by fusion in large quantities is so costly (energy-wise and therefore money-wise), that it is just extraordinarily unprofitable to do that. |
i lit a mosquito coil and used it to melt down small down candle wax which was fallen on the floor,the coil then produced some dense fumes,i directed the fumes to the flame of a candle,as soon the fumes reached the candle,my coil caught fire again and started burning,i mean the flame actually traveled the path of the f... |
I lit a mosquito coil and used it to melt down small down candle wax which had fallen on the floor. The coil then produced some dense fumes. I directed the fumes to the flame of a candle. As soon the fumes reached the candle, my coil caught fire again and started burning. I mean the flame actually traveled the path of ... |
How do they find out exactly what reactions they can use to produce some substance they want to produce? Is there some reaction database that helps them find a way to make the target substance out of available chemicals?
For example, let's say they want to produce ethanol. There are multiple ways to do this: they co... |
How do chemists find a procedure to produce a given substance? |
Chemists use many sources of information to do this.
Part of being trained as a chemists is learning, in general terms, what kinds of reactions are known and what their best uses are. That training can go 5-10 years beyond a bachelors degree and is very intensive.
Beyond what you can keep in your head, one of the... |
[The current version of the CTFile spec](http://accelrys.com/products/informatics/cheminformatics/ctfile-formats/no-fee.php) can be downloaded for free from Accelrys. Based on the files you have, you'll want to look at the "V2000" section.
Short answer: I believe [M ZZE] is a vendor-specific property key, possibly ... |
Is:
2,3-dimethyl prop-1-ene a possible organic structure?
I am not sure how to approach this, what would the correct name of this molecule be? |
Is this a possible organic structure? |
Is there a chemical that has the bond structure like below?
(sorry, I found I could not upload the picture. So, I need to describe as below.)
There are 5 atoms linking together.
Two of them have 4 bonds. (They can be either same or different atoms.)
Another two of them have 3 bonds. (They can be either same or di... |
Is there a chemical looks like this? |
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