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My answer to this question is the following. Nodes can happen for highly excited states, whose average distances are typically much larger than the Bohr radius. Consider Na, Cs etc, which have one outermost shell electron. When the outermost shell electron is highly excited, the case is not much different from that of ... |
Can somebody explain as concrete as possible, how the change of **temperature** and the change of **ph** leads to deviations of this law ? |
I've been taught that if you have two aqueous reactants that react together and produce heat it is exothermic. Shouldn't that be endothermic? Did my professor misspeak?
If it's gaining heat, that means it's pulling heat from the outside. The opposite of what happens when water freezes and releases heat (which is act... |
Why is it that reactions that cause an increase of temperature are exothermic? |
It can form a square planar and a tetrahedral complex but within square planar or within tetrahedral can there be isomers possible? |
what are possible isomers of (meso-stilbenediamine)(isobutylenediamine) palladium (II)? |
How do bond angles vary in molecules with a lone pair and central atom of different electronegativity, but in the same period so that electronegativity matters more than orbital size? Let's assume that the molecules I am comparing have the same substituents and one lone pair.
Will the molecule with the more electron... |
Plaques are continually being removed by natural mechanisms within the body. Statin use, when combined with aggressive dietary changes, can slow down the rate of plaque deposition such that the rate of plaque removal is faster than plaque deposition and plaque thinning can be observed.
Doing this faster (plaque liq... |
Plaques are continually being removed from arteries by natural mechanisms within the body. Statin use, when combined with aggressive dietary changes, can slow down the rate of plaque deposition to the point that the rate of plaque removal is actually higher than the rate of plaque deposition, and, as a consequence, pl... |
Alright, so Tin ions in most of it's salts have the propensity to form Tin(II,IV) Hydroxides and then precipitating out of aqueous solutions. What can I throw in the solutions to prevent this? Using Tin Fluoroborate doesn't precipitate Hydroxides, but I don't have access Fluoroborates. I really don't want very acidic s... |
I'm looking to create a light up dancing pole. This requires a **translucent** material that is strong enough to support the weight and force of a human being, even when it's hollowed out to so LEDs can go inside. The material must also be reasonably affordable, so something like diamond is out of the question.
I'v... |
Chemistry of Stripper Poles: How much weight can different materials support? |
I'm looking to create a light up dancing pole. This requires a **translucent** material that is strong enough to support the weight and force of a human being, even when it's hollowed out to so LEDs can go inside. The material must also be reasonably affordable, so something like diamond is out of the question.
I'v... |
Need of hyper conjugation? |
why chelates which form 3 or 4 member rings or 6 or 7 member rings are as stable as 5 member ring chelates?
for example if we measure stability of chelates with oxygen donors, say oxalate, malonate, succinate etc oxalate chelated with metal shoes more stability. why malonate , succinate as chelating ligands are less ... |
Why member ring is favoured in chelates? |
My textbook says that $\ce{[CrF6]^{3-}}$ is an example of $sp^3d^2$ hybridization. But I don't really see how. Chromium has an electronic configuration of:
$$3d: \boxed{\uparrow}\boxed{\uparrow}\boxed{\uparrow}\boxed{\uparrow}\boxed{\uparrow} \ 4s: \boxed{\uparrow}$$
Give three more electrons and it might look so... |
How does CrF₆³⁻ hybridize? |
Why does Pb normally have an oxidation number of +2? |
If a reaction is endothermic, then the reaction must take energy from the environment to occur (as far as I know), and if this is the case, then to me the reaction seems energetically unfavorable, as there is only so much energy you can get from the environment. Does this means all naturally occurring reactions, (that ... |
Are all naturally occuring reactions exothermic? |
Suppose I am given following reaction in vessel
$$\ce{NH4HS_(s) <=> NH3(g) + H2S(g)} $$
$P_{NH_3}=P_{H_2 S}=1\:atm $ at Equilibrium , If volume is doubled at this instant then what would be $P_{NH_3}$ at new equilibrium?
I know that as soon as volume is doubled pressure would drop to half at this instant and $K_... |
Suppose I am given following reaction in vessel
$$\ce{NH4HS_(s) <=> NH3(g) + H2S(g)} $$
$P_{\ce{NH3}}=P_{\ce{H2S}}=1\,\mathrm{atm}$ at Equilibrium , If volume is doubled at this instant then what would be $P_{\ce{NH3}}$ at new equilibrium?
I know that as soon as volume is doubled pressure would drop to half at... |
I realise, that this question is a stretch, but I was wondering, how would a bonding orbital be called if it was formed from two $f_{x(x^2−3y^2)}$ or $f_{y(3x^2−y^2)}$ orbitals. Have there been any suggestions on this, was it anywhere proposed or discussed? I am not arguing about the existence of such a thing, but as a... |
What would follow in the series sigma, pi and delta bonds? |
The value of electronegativity of A and B are 1.2 and 4 respectively. Find the percentage ionic character of A-B bond.
I know that the percentage ionic character is :-
(Observed value)/(Theoretical value)
How is electronegativity used here? |
The title's pretty much it. At school, we're taught that ionic substances are composed of an infinitely-repeating lattice, with atoms at fixed angles from other atoms. How is this possible when I can get an individual grain of salt? Clearly if there's an individual grain, it can't be infinitely repeating. |
How can ionic substances have an infinitely-repeating lattice structure? |
I am teaching my students how to write the electronic configuration of the elements of the periodic table.
Thus, following the rules on how to fill the orbitals, the electronic configuration of iron (for example) is 1s2 2s2 2p6 3s2 3p6 4s2 3d6 , thus, it is abbreviated form is [Ar] 4s2 3d6.
However, I has not be... |
Suppose I am given following reaction in vessel
$$\ce{NH4HS_(s) <=> NH3(g) + H2S(g)} $$
$P_{\ce{NH3}}=P_{\ce{H2S}}=1\,\mathrm{atm}$ at Equilibrium , If volume is doubled at this instant then what would be $P_{\ce{NH3}}$ at new equilibrium?
I know that as soon as volume is doubled pressure would drop to half at... |
Are there any STP liquids not containing large amounts of hydrogen and oxygen that are safe for human contact? |
By this, I mean if I buy compressed dry air from somebody like British Oxygen how much variation in composition might I expect between batches? For example, is Argon evenly distributed globally, by height, by geography etc? Is CO2 removed? Are contaminants filtered out eg NOx? |
How chemically homogeneous is air? |
Is there any paper making alternative? What is there in trees that makes it the only thing from which paper can be made? Do we even need paper anymore with all electronic devices and stylus', etc |
Why does the graph of compressibility factor(z) vs pressure increase after reaching the minimum? |
Epoxides are stable because, first and foremost, they are ethers. Ethers are an exceptionally unreactive functional group. Why? Because alkoxides are poor leaving groups that do not participate in many common nucleophile-electrophile reactions (e.g., SN2). Of course, there are ways to force ethers to react, such as thr... |
Pressure is the magnitude (absolute value) of the force over the area, so how can that result in a negative value for pressure as would happen in [certain circumstances](http://en.wikipedia.org/wiki/Pressure#Negative_pressures)<a href="http://en.wikipedia.org/wiki/Pressure#Negative_pressures">? |
How can you achieve negative pressure? |
Let's say I have a sample of 2 (assumingly different) diatomics A and B.
Through Spectroscopy I found the data below:
For molecule A:
$$B ̃=2.17690\space cm^{−1}$$
$$D ̃=4.79000×10^{-5} cm^{−1}$$
$$I=1.28590×10^{-46} kg\space m^2$$
$$ν ̃_e=928.15\space cm^{−1}$$
For molecule B:
$$B ̃=1.51695\space cm^{−... |
Lets say that a in a compound A-B, electronegativity of A is x and that of B is y,what will be the percentage ionic character in terms of x and y?
I have been taught that the percentage ionic character is :-
(Observed value of ionic character ) / (calculated value of character)
But I can't understand how is ... |
Lets say that a in a compound A-B, electronegativity of A is x and that of B is y,what will be the percentage ionic character in terms of x and y?
I have been taught that the percentage ionic character is :-
(Observed value of ionic character) $÷$ (calculated value of character)
But I can't understand how is e... |
Recently there has been announced a new 3d printing technology which uses UV light, from lasers or a projector, to harden slices of epoxy resin so that the printed object rises out of a pool of epoxy.
There is some information about an oxygen boundary and UV light, can someone explain the chemistry of the process? ... |
How does 3dCarbon CLIP printer work? |
What does this sentence mean - I assumed that burning vaporised something? If something is vaporised, isn't that turning it into a gas? How can you burn a gas? This is a sentence in my AS Chemistry book and I am obviously missing something.
"Alkanes must be vaporised before they will burn" |
"Alkanes must be vaporised before they will burn" - what does this mean? |
By this, I mean if I buy compressed dry air from somebody like British Oxygen how much variation in composition might I expect between batches? For example, is Argon evenly distributed globally, by height, by geography etc? Is $\ce{CO2}$ removed? Are contaminants filtered out eg $\ce{NOx}$? |
Paper mostly consists of cellulose, form which wood is a good source.
Another interesting source is the hemp plant and it seems that hemp was indeed the major source in paper manufacturing up to the 19th century.
Nowadays, recycling of paper probably is the most reasonable way to reduce the wood use.
>Do we ev... |
Are there positive ligands which can bind to the central metal atom to form co-ordination compounds?
My thoughts:I know that ligands are Lewis bases which donate a pair of electrons and the central metal will be a lewis acid. So, positive ligand means it is deficient of electrons.
In that case there is no electron ... |
**Why is the basicity of para->meta->Aniline>ortho-
for Phenyldiamine?**
(pKa:ortho-9.53,meta-9.12,para-7.96)
Ok i tried deducing using resonance and inductive effects but got stuck.Help Please. |
Why H-OH is more acidic than CH3-OH? A common answer to this question is because of +I of CH3 the -ve charge at O increases making it less acidic. But if we compare electronegativity difference, the difference in EN of O and H is more than that of O and C so there should be even more -ve charge at O in case of H2O. In ... |
Why H-OH is more acidic than CH3-OH? |
Why H-OH is more acidic than CH3CH2-OH? A common answer to this question is because of +I of CH3 the -ve charge at O increases making it less acidic. But if we compare electronegativity difference, the difference in EN of O and H is more than that of O and C so there should be even more -ve charge at O in case of H2O. ... |
Why H-OH is more acidic than CH3CH2-OH? |
I know Sorbitol, $\ce{C_6H_14O_6}$ $$\ce {C(OH)H_2 (C(OH)H)_4C(OH)H_2}$$is soluble in water however I did not have much luck finding out whether or not it is soluble in ethanol. My guess is that it isn't however I am not so sure.
Is Sorbitol soluble in ethanol? |
Does sorbitol dissolve in ethanol? |
Why $\ce{H-OH}$ is more acidic than $\ce{CH3CH2-OH}$? A common answer to this question is because of +I of $\ce{CH3}$ the -ve charge at $\ce{O}$ increases making it less acidic. But if we compare electronegativity difference, the difference in EN of $\ce{O}$ and $\ce{H}$ is more than that of $\ce{O}$ and $\ce{C}$ so th... |
> Does this means all naturally occurring reactions, (that don't just
> happen once in a blue moon but at a steady rate) are exothermic?
**No**, not all naturally occurring reactions are exothermic ($\Delta H > 0$) or exergonic ($\Delta G > 0$). For example, the reaction fundamental to our existence, photosynthesi... |
does tetramine copper dissolve cellulose? |
I saw a Youtube video which showed that cotton (cellulose) dissolves in deep blue solution of tetramine copper made by adding 20% ammonia in copper carbonate salt. I tried to replicate the process using $\ce{CuSO4}$ and copper chloride. None worked. Where have I gone wrong? |
Does tetramine copper dissolve cellulose? |
Is there any difference between the phrase "continuously overlapping p-orbitals" and "conjugated pi bonds" when referring to aromatic compounds? I've heard both used and I wasn't sure if they mean the same thing. |
Interesting question!
To have **continuously** overlapping p-orbitals, the p-orbitals must be arranged in a cyclic loop. The p-orbitals in benzene are continuously overlapping. The p-orbitals in benzene are also conjugated pi bonds.
![enter image description here][1]
[image source][2]
In buta-1,3-diene th... |
Need of hyperconjugation? |
This compound can't exist. There is no such anion such as $\ce{FO3-}$, why not ?
Because fluorine is more electronegative then oxygen so that anion just can't be formed. Therefore no $\ce{FO3-}$ to combine with $\ce{K+}$ therefore no such compound is present. |
It has been already mentioned in the comments and the other answer, that fluorine is more electronegative than oxygen. Therefore it is highly unlikely that this compound exist.
To illustrate the problem at hand, take a look at the only known compound with a fluorine oxygen bond: [Hypofluorous acid][1], $\ce{HFO}$, w... |
As the compound potassium chlorate exists, is there something as $\ce{KFO3}$?
All the other halogenates are mentioned somewhere on the web but what about this?
If no, then why? |
Does the compound KFO₃ exist? |
I was wondering whether the following order is correct :
In the first inequality , how come 9 hyperconjugation dominated resonance effect of benzene ring?
In the last inequality doesn't 2 HC of vinylic carbocation overpow... |
**Why is the basicity of para->meta->Aniline>ortho
for Phenyldiamine?**
($pK_a$: ortho-9.53, meta-9.12, para-7.96)
Ok I tried deducing using resonance and inductive effects but got stuck.Help Please. |
Why is the basicity of para- > meta- > Aniline > ortho
for Phenyldiamine?
($\mathrm{p}K_a$: ortho-9.53, meta-9.12, para-7.96) I tried deducing it using resonance and inductive effects but got stuck. |
How to rationalise the basicity order of phenyldiamine? |
How to calculate the bond energy of C-Cl? |
In most cases of substituents , mesomeric effect is considered stronger and more dominating than the inductive effect .
A notable exception are the halogens .
- What is the reason behind this ?
I got the answer [here][1].
- If its about the EN , then would all other electronegative elements with lone ... |
The pseudo 1st order reaction happens when one of the reactant is in large excess and its concentration doesnt change during the reaction .
Is there any other such situation when a _certain_ higher order reaction turns out to become a pseudo first order kinetic reaction (except the situation where an N$^{th}$ orde... |
So group 17, 16, and 15, are called the halogens, chalcogens, and pnictogens respectively. Is there a name for the groups 14 and 13?
*(I really don't know if this is on topic here if it isn't tell me and I will move it.)* |
Name for carbon and boron groups? |
Name for group IV (A) and group III (A) elements? |
Name for carbon and boron groups? |
What are the steps to follow to determine which has a higher bond order say $\ce{CO}$ and $\ce{CO3^{2-}}$ by drawing the Lewis structure? |
We need a pure copper phthalocyanine for our experiments. Of course, we can buy it from Sigma Aldrich, but this means we'll have to wait a while. In local area we can buy only dyes which are about 98% purity, which is not enough. Is there any fast and easy method to purify it in lab? |
I am planning to use poly dimethyl siloxane (PDMS) to create phantom for mimicking tissue for imaging. For this, I plan on using [SYLGARD® 184][1], which is a viscous liquid. When adding other components to it, the air bubbles will be introduced. I have learned that one way (available to me) is using the negative press... |
I am planning to use polydimethylsiloxane (PDMS) to create phantom for mimicking tissue for imaging. For this, I plan on using [SYLGARD® 184][1], which is a viscous liquid. When adding other components to it, the air bubbles will be introduced. I have learned that one way (available to me) is using the negative pressur... |
A rule of thumb in chemistry is that a reaction doubles in rate for every 10 °C increase in temperature. Considering the impact of a 10 °C increase in global temperature, would the same rule apply to kinetic weather processes – for example, would the average wind speed around the world double? |
I have looked at GAMESS and Gaussian manuals but can not find the maximum number of **efficient** nodes. As I tried GAMESS on our supercomputer, I can add as many CPUs as I want but it really does not Improve the calculation time and efficacy . On the other hand just adding maximum number of CPUs is just waste of CPU-H... |
GAMESS and Gaussian : what is the maximum efficient number of supported nodes? |
I assumed it would increase, but I think I am wrong. I know that when the forces are strong, the vapor pressure would decrease. Does this same principle apply to the IM forces increasing? |
When the intermolecular forces in a liquid increase, does the equilibrium vapor pressure of the liquid at a given temperature increase or decrease? |
The equation we need it to change to FeO+CO------->Fe+Co2
The three equations and delta heat:
3Fe2O3 + CO---->2Fe3O4+CO2 Delta Heat= -47.0kJ
Fe2O3+3CO------>2Fe+3CO2 Delta Heat= -25.0 kJ
Fe3O4+CO------->3FeO+CO2 Delta Heat= 19.0kJ
What is the enthalpy change and how to combine t... |
What is the enthalpy change for the following equation? |
What form is the ionic equalibrium equation? I have problem asking for it, but I'be done so many different equalibrium equations that I'm starting to get mixed up on which one is called what... Which one is it? |
The equation we need it to change to
\\[\ce{FeO + CO ->Fe + CO2}\\]
The three equations and delta heat:
\\[
\begin{align*}
\ce{3Fe2O3 + CO &-> 2Fe3O4 + CO2} &\Delta H=-47.0\ \mathrm{kJ}\\
\ce{Fe2O3 + 3CO &-> 2Fe + 3CO2} &\Delta H=-25.0\ \mathrm{kJ}\\
\ce{Fe3O4 + CO &-> 3FeO + CO2} &\Delta H= 19.0\ \mathrm{k... |
> […] how to combine the 3 equations […]
###**Equations** is the keyword!
This is just an example on how to solve a system of linear equations, disguised as a chemistry problem.
If the calculation with $\ce{FeO}$, $\ce{CO}$, $\ce{Fe}$, $\ce{CO2}$, etc. feels strange, just translate them to $x_1$... |
> Is there any criteria for selection of best number of CPUs for optimum
> resource usage?
The criteria is basically the same as for choosing the level of theory: *benchmarking*. Parallel scaling depends on many factors: the level of theory, the size of the molecule, the machine architecture, etc., so there is no g... |
Why does the color of iodine differ when it forms a charge transfer complex with benzene (pi donor) - pink and ethanol (electron pair donor) - brown? Does the HOMO-LUMO energy differ, if so how? |
I have to convert a whole lot of nutrient data : NH4, PO4 and NOx data that is in µg/L into mM (millimolars).
Could someone give me an example for 26.62 NOx µg/L? or 7.73 PO4 µg/L? or 14.39 NH4 µg/L?
I have a large data set in Excel to convert and send to someone and want to get it right...any help would be rea... |
Converting 26.62 NOx µg/L into mM (millimolars)? |
I have to convert a whole lot of nutrient data : $NH_4$, $PO_4$ and $NO_x$ data that is in µg/L into mM (millimolars).
Could someone give me an example for 26.62 $NO_x$ µg/L? or 7.73 $PO_4$ µg/L? or 14.39 $NH_4$ µg/L?
I have a large data set in Excel to convert and send to someone and want to get it right. Any ... |
I have to convert a whole lot of nutrient data : $\ce{NH_4}$, $\ce{PO_4}$ and $\ce{NO_x}$ data that is in µg/L into mM (millimolars).
Could someone give me an example for 26.62 $\ce{NO_x}$ µg/L? or 7.73 $\ce{PO_4}$ µg/L? or 14.39 $\ce{NH_4}$ µg/L?
I have a large data set in Excel to convert and send to someone ... |
> At the anode, hydrogen is oxidised (losing electrons). My first question is this: why is the anode negative if it is attracting electrons?
It is not attracting electrons, it is attracting hydrogen atoms. The electrode binds the hydrogen and releases the electrons. The electrons are then able to flow out through th... |
From what I understand, adding NaOH to a solution containing transition metal ions gives transition metal hydroxide precipitates. Why is NaOH soluble but transition metal hydroxides insoluble? I have a feeling it has something to do with ligands and complexes formed, which I am familiar with.
Thank you in advance :) |
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