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If we have a metal in gas phase. Suppose lets say Aluminum. Aluminum has delocalised electrons. There is Al cation -electron attraction in it. Its easier to visualize Al atomic structure in solid form. But if its in gas phase will delocalised electrons return to the atom itself or there is going to be electrons and cat... |
If we have a metal in gas phase. Suppose lets say Aluminum. Aluminum has delocalised electrons. There is Al cation -electron attraction in it. Its easier to visualize Al atomic structure in solid form. But if its in gas phase will delocalised electrons return to the atom itself or there is going to be electrons and cat... |
Not that long ago, scientists noticed that at the end of each DNA strand there were thousands of nucleotides. Nucleotides are used for genetic coding. That is to say, certain sequences of nucleotides instruct the body to synthesize certain proteins when the genetic code in the DNA is being read. DNA is really like ... |
We have UV SHİMADZU 2550 and its diffuse reflectance attachment. I want to measure band gap of single crystal samples. What should I do? Which formulas should I use to calculate band gap? I don't have much sample... |
I know a lot of chemists like to quote pKa values and subtract them to reinforce some notion about some acid-base reaction being highly favorable or highly unfavorable or whatnot.
For example, the pKa of acetic acid is about 5 and the pKa of LDA's conjugate acid is about 36. 36 minus 5 gives us 31 "zeros" of favora... |
According to Wikipedia the conjugate acid of LDA has a pKa of about 35 - which is in line with figures I've seen elsewhere.
How then can such a weak acid's pKa of be determined? If the determination is made in water, how is that even possible? Water would be a stronger acid by far and couldn't it easily mask the aci... |
How is the pKa of extremely weak acids determined? |
**Ageing is a disease. Just as treatments have been found for other diseases, ageing can be slowed or reversed as well.**
Not that long ago, scientists noticed that at the end of each DNA strand there were thousands of nucleotides. Nucleotides are used for genetic coding. That is to say, certain sequences of nucl... |
When and why do hot material take heat from cold material? |
So my textbook gives me this random equation:
$\Delta U = q + w$. Then consider two conditions, under constant pressure and under constant volume. Because $w = -P\DeltaV$, constant volume will make $\DeltaU = q$. And constant pressure equation is basically the same.
But why is isn't heat under neither condition consi... |
Why heat of reaction under neither constant pressure or constant volume is considered (in my textbook, or probably somewhere else)? |
So my textbook gives me this random equation:
$\Delta U = q + w$. Then consider two conditions, under constant pressure and under constant volume. Because $w = -P\Delta V$, constant volume will make $\Delta U = q$. And constant pressure equation is basically the same.
But why is isn't heat under neither condition ... |
[IMG]http://i61.tinypic.com/qrf70l.jpg[/IMG]
Hi there, i would like to ask about the rate of hydrolysis for these compounds A to D. I know that hydrolysis depends on the positive charge of the carbonyl carbon and also the substituent around it eg electron withdrawing.
Therefore, from the picture above i can see t... |
![enter image description here][1]
Hi there, i would like to ask about the rate of hydrolysis for these compounds A to D. I know that hydrolysis depends on the positive charge of the carbonyl carbon and also the substituent around it eg electron withdrawing.
Therefore, from the picture above i can see that compou... |
There is no _chemical_ reason why life couldn't be prolonged at least _somewhat_. There are a huge variety of undesirable biochemical reactions (oxidation of proteins for instance) that cells must deal with as part of being alive, and given that _lineages_ are immortal (as the process of growing up and creating germ c... |
The constant pressure and constant volume scenarios are presented when you first study thermodynamics because they present an easy way to simplify the calculation of energy changes ($\Delta U,\ \Delta H,$ etc.) based on the change of one easy to measure phenomenon.
>Internal Energy $U$
So, the change in internal ... |
I want to know why concentration of solids and liquids are taken unity in expression of equilibrium constant( heterogenous equilibrium). It is usually mentioned that the density of solids and liquids( ideally) does not change and hence concentration does not change and so rate does not depend on solids and liquids. I a... |
Looks like you understand pH measurement, but you are trying to go deeper into the details of potentiometry and open circuit potential measurements.
There I would recommend the basic electrochemistry texts. Here is one simple text that is cheap, easy to read and very informational:
[Electrode Potentials; Richard ... |
Looks like you understand pH measurement, but you are trying to go deeper into the details of potentiometry and open circuit potential measurements.
There I would recommend basic electrochemistry texts. Here is one simple book that is cheap, easy to read and very informational:
[Electrode Potentials; Richard G. C... |
![enter image description here][1]
Hi there, i would like to ask about the rate of hydrolysis for these compounds A to D. I know that hydrolysis depends on the positive charge of the carbonyl carbon and also the substituent around it eg electron withdrawing.
Therefore, from the picture above i can see that compou... |
according to the nerst equation, The electrode potential is the SEP minus RT/nF ln([m]/[mn+]).
Question is, why? Assuming a simple galvanic cell, we know that in general if the temperature is increased, there should be more collisions of the solution with the electrode, resulting in a higher accumulation of the meta... |
Why does an increase in temperature decrease the EP? |
What mass of aromatics are airborne in scented environments for example in a perfume deparment?
What is the minimum g/m3 of aromatics that a human can detect, and how much is present when it evaporates from an oven, in a cookie shop, from a cut lawn, near a perfumed lady and average levels from a day of walking.
... |
What mass of aromatics does a cubic meter of air contain near an oven? |
Are there examples of UV-Vis emission from charge-separated states? The cases I have encountered have only absorption. Is the recombination process of a nonradiative kind by necessity? |
UV-Vis emission from charge-separated states? |
Can H2O donate it's lone pairs as coordinate bonds at the same time? |
I recently noticed that whenever I washed the egg yolk stuck on some utensils the water becomes milky white.
It has to be the egg yolk that turns white and give off the white color to water right?
|
Why does egg yolk turn white when washed with water? |
This is what I read on [Chemwiki][1]:
> Rudolf Clausius was a German physicist, and he developed the Clausius statement, which says "Heat generally cannot flow spontaneously from a material at a lower temperature to a material at a higher temperature." However, there is one exception to this statement and that is so... |
Can any atom donate more than 1 lone pair as a coordinate bond to the same metal? |
Why is fat nonpolar while water is polar?
in water there is the H-O bond and the O is more negative, we have
dipole = charge * distance
in a fat molecule it's like
H-O-C-C-C-C-C-C ...
but the carbon atoms doesn't matter, the polarity is still q*d, as in the water molecule, so they should have the same amount of ... |
why is fat nonpolar? |
I posed [this question](http://cooking.stackexchange.com/questions/56153/lime-substitute-for-nixtamalizing-corn) at the Seasoned Advice SE and thought I might get some more information here.
[Traditionally prepared corn](http://en.wikipedia.org/wiki/Nixtamalization) is cooked in a calcium hydroxide solution to make ... |
A common science demonstration is to [float a "boat" on sulfur hexafluoride][1].
How long would the sulfur hexafluoride stay in the container (in the experiment linked above) if the container were to be left uncovered and undisturbed at room temperature?
Also, I'm wondering what would happen if you scaled the exper... |
How quickly does sulfur hexafluoride mix with the atmosphere? |
These are minerals that are naturally present in "tap" water. Chemically, they are most likely a mixture of calcium carbonate and magnesium carbonate, both of which are only very lightly soluble in water.
As you boil away the water, these dissolved calcium/magnesium carbonates remain behind and their concentrations ... |
I posed [this question](http://cooking.stackexchange.com/questions/56153/lime-substitute-for-nixtamalizing-corn) at the Seasoned Advice SE and thought I might get some more information here.
[Traditionally prepared corn](http://en.wikipedia.org/wiki/Nixtamalization) is cooked in a calcium hydroxide solution to make ... |
These are minerals that are naturally present in "tap" water. Chemically, they are most likely a mixture of calcium carbonate and magnesium carbonate, both of which are only very lightly soluble in water.
As you boil away the water, these dissolved calcium/magnesium carbonates remain behind and their concentrations ... |
I have been reading about resolution in mass spectrometry and there are a few things I do not understand.
The resolving power is determined by $m/(m_2-m_1)$ at full width half height of a peak. The higher the value obtained the better. This is where I struggle to form a link between the resolution of the mass spectr... |
Calculate the pH at the equivalence point for the titration of 0.130 M methylamine (CH3NH2) with 0.130 M HCl. The Kb of methylamine is 5.0× 10–4.
So I started with the equation: $$\ce{HCl + CH3NH2<=>CH3NH3+ + Cl-}$$
and then I knew that pH = pKa + log([base/acid])
So, I put log(0.130/0.130) = log(1) = 0 and then ... |
Why do most all double replacement reactions result in a precipitate and an aqueous molecule? Is it because the individual solute molecules always form stronger bonds such as how in single replacement the molecule with more energy bonds with the molecule of the opposite charge? |
I took an interest in this question because it's something I recently wondered myself. First of all, I should clarify that while you mention *hypervalency*, what you seem interested in is *hypercoordination*, or even more generally, just compounds with high [coordination numbers](http://en.wikipedia.org/wiki/Coordinati... |
I took an interest in this question because it's something I recently wondered myself. First of all, I should clarify that while you mention *hypervalency*, what you seem interested in is *hypercoordination*, or even more generally, just compounds with high [coordination numbers](http://en.wikipedia.org/wiki/Coordinati... |
Why is fat nonpolar while water is polar?
In water there is the $\ce{H-O}$ bond and the $\ce{O}$ is more negative, we have
$\text{dipole = charge}* \text{distance}$
A fat molecule is like
$\ce{H-O-C-C-C-C-C-C...}$
but the carbon atoms don't matter, the polarity is still ${q*d}$, as in the water molecule, so th... |
Why is fat nonpolar? |
I took an interest in this question because it's something I recently wondered myself. First of all, I should clarify that while you mention *hypervalency*, what you seem interested in is *hypercoordination*, or even more generally, just compounds with high [coordination numbers](http://en.wikipedia.org/wiki/Coordinati... |
[Liquid nitrogen][1] seems to be attracting a bit of attention at the moment as a medium of energy storage, both for electricity grid applications and for transport.
For example, [Highview][2] are doing round-trip electricity storage via liquid nitrogen.
![enter image description here][3]
The [Dearman Engine ... |
Why does a dianon (such as malonate) bind cations more strongly than its equivalent anion (acetate)?
Is it simply because of the proximal availability of another O- group that can bind to cations? Does the second COO- group on malonate distribute charge in a better way that can allow for stronger binding? |
Why do dianons (such as malonate) bind cations more strongly than anions? |
Why does a dianion (such as malonate) bind cations more strongly than its equivalent anion (acetate)?
Is it simply because of the proximal availability of another O- group that can bind to cations? Does the second COO- group on malonate distribute charge in a better way that can allow for stronger binding? |
Why do dianions (such as malonate) bind cations more strongly than anions? |
This is known as the chelate effect.
The main reason why you observe this is that cations in solution have an ordered solvent shell around them, especially in polar solvents where there will be defined solvent geometry around the shell; often octahedral for metal ions in water. The formation of a complex with a bid... |
Now A transition element is one which forms one or more stable ions which have partially filled d-orbitals. Maganase (Mn) could have an oxidation state of 7+ which means that it will lose all of the 3d5 and 4s2 electrons. So how could make a 7+ ion in that case (which means that it will lose all of the 4s2 and 3d5 elec... |
Calculate the pH at the equivalence point for the titration of 0.130 M methylamine ($\ce{CH3NH2}$) with 0.130 M $\ce{HCl}$. The Kb of methylamine is ${5.0×10^{–4}}$.
So I started with the equation:
$$\ce{HCl + CH3NH2<=>CH3NH3+ + Cl-}$$
and then I knew that $pH = pKa + \log \left( \frac{[base]}{[acid]} \right)... |
Your idea seems mostly sound, but one thing you should consider is the solubility of calcium hydroxide (a.k.a. slaked lime). It is fairly low.
That low solubility provides you with an opportunity. If you have calcium chloride and sodium hydroxide, you can mix saturated solutions of both and a white precipitate s... |
Your idea seems mostly sound, but one thing you should consider is the solubility of calcium hydroxide (a.k.a. slaked lime). It is fairly low.
That low solubility provides you with an opportunity. If you have calcium chloride and sodium hydroxide, you can mix saturated solutions of both and a white precipitate s... |
Computer killed by insecticide; what compounds are likely? |
Consider a misture made up of alcohol and water at room temperature. If I freeze this misture, why does it change its temperature during the phase change? I don't understand the difference between the case when you have a pure substance (only water or only alcohol) and that one. How could it be different (I mean, in mo... |
Why does the misture's temperature change while phase transition? |
Consider a misture made up of alcohol and water at room temperature. If I freeze this mixture, why does it change its temperature during the phase change? I don't understand the difference between the case when you have a pure substance (only water or only alcohol) and that one. How could it be different (I mean, in mo... |
Consider a mixture made up of alcohol and water at room temperature. If I freeze this mixture, why does it change its temperature during the phase change?
I don't understand the difference between the case when you have a pure substance (only water or only alcohol) and that one. How could it be different (I mean, i... |
Why does the mixture's temperature change while phase transition? |
Ingredients
--
So we could probably guess what's in the insecticide based on what's used in some of their other products.
[Black Flag Flying Insect Killer][1]
--
Tetramethrin - Sounds like the "active ingredient" here. By "active ingredient, I mean poison.
d-phenothrin - Another poison. This product sound... |
Ingredients
--
So we could probably guess what's in the insecticide based on what's used in some of their other products.
[Black Flag Flying Insect Killer][1]
--
Tetramethrin - Sounds like the "active ingredient" here. By "active ingredient", I mean poison.
D-phenothrin - Another poison. This product soun... |
Ingredients
--
So we could probably guess what's in the insecticide based on what's used in some of their other products.
[Black Flag Flying Insect Killer][1]
--
Tetramethrin - Sounds like the "active ingredient" here. By "active ingredient", I mean poison.
D-phenothrin - Another poison. This product soun... |
What are the possible resonance structures for $\ce{ClO_2^-}$? Assigning one double bond to the structure makes for formal charges of $\ce{O (-1) - Cl (0) = O (0) <-> O (-1) = Cl (0) - O (-1)}$. It appears that the same set of formal charges can be achieved with two double bonds (expanding the octet on $\ce{Cl}$ to 12 ... |
What are the resonance structures for chlorite anion? |
Here is something I found, on weak polyprotic acids, that I think answers the question:
![enter image description here][1]
[1]: https://i.stack.imgur.com/9I2Cu.png
So then [$\ce{SO3^{2−}}$] $= 6.4 \cdot 10^{-8}$? |
Why does NaCl dissolve in H2O despite its strong ionic bond? |
From the answer of John Snow I saw that it contained `Petroleum Distilates`
From my years as IT tech it was absolutely forbidden to use any Petrolium/oil based product for cleaning out the computer parts, because they cause corrosion/react with the compounds.
The acidity of crude oil based products is just too hi... |
What exactly is Indium's ability to stabilize non-ferrous metals? |
From the answer of John Snow I saw that it contained `Petroleum Distilates`
From my years as IT tech it was absolutely forbidden to use any Petrolium/oil based product for cleaning out the computer parts, because they cause corrosion/react with the compounds.
The acidity of crude oil based products is just too hi... |
2-Chloro-3,3-dimethylbutane or 3-Chloro-2,2-dimethylbutane?
According to these sources both are correct:
1. [NIST/TRC Web Thermo Tables (WTT)](http://wtt-pro.nist.gov/wtt-pro/index.html?cmp=2-chloro-3.3-dimethylbutane)
2. [ChemSpider](http://www.chemspider.com/Chemical-Structure.455173.html)
![Pict... |
What is has a higher priority in naming organic compounds, alkyl groups or halides? |
> The obvious order is via the stability of the carbocation of the group.
I think you meant the migrating groups stability?
This is not what textbooks say.
Reactions are ruled by the $ΔG$ of the activated complex.
This may be close to educts, or to products, or some halfway
state or a real intermedia... |
For carbonates and bicarbonates i know that stability increases down the group.And for chlorides and flourides stability decreases down the group.Why is it so?
Can someone explain it in details!!!
(I am talking of s block alkali metals) |
Will the Sulfur-Iodine cycle and Haber Method work at lower pressures and temperatures? |
Woody biomass is composed of cellulose, hemicellulose, and lignin components. The following diagram provides representative formulas for each component:
![biomass components][1]
Biomass can be represented by it's density, ultimate analysis, and composition. For example, beech wood can be represented by its densit... |
Woody biomass is composed of cellulose, hemicellulose, and lignin components. The following diagram provides representative formulas for each component:
![biomass components][1]
Biomass can be represented by it's density, ultimate analysis, and composition. For example, beech wood can be represented by its densit... |
An equation of heat is $q = s \cdot m \cdot\Delta T$. I know that $\Delta T$ can be in either degree Celsius ($^\circ{}\mathrm{C}$) or kelvin ($\mathrm{K}$). However, one thing that confuses me is how the units cancel if $\Delta T$ is in degree Celsius. How does this work? |
The boiling point of an aqueous solution containing sucrose (C12H22O11) is 101.45 °C. Calculate the osmotic pressure of this
solution at 35 °C, at which the solution density is 1.036 g/mL.(kb = 0.512°C/m) (37.6 atm)
(The one in braces is an answer)
I did it in this step:
First I use delta Tb = kb*m
And substitut... |
The boiling point of an aqueous solution containing sucrose ($\ce{C12H22O11}$) is 101.45 °C. Calculate the osmotic pressure of this
solution at 35 °C, at which the solution density is 1.036 g/mL. ($kb = 0.512°C/m$) (37.6 atm)
(The one in braces is an answer)
I did it in this step:
First I use $\Delta T_b = k_bm$
... |
> I did it in this step: First I use ΔTb=kbm And substitute following Tb=101.45 and kb=0.512 I get m=198.144 mol/kg
This should be the first clue that something went wrong. 198 mol of sucrose is about 67 ***kilograms*** of sucrose, so your implied molality means that for every kg of water, there are 67 kg of sucros... |
The boiling point of an aqueous solution containing sucrose ($\ce{C12H22O11}$) is 101.45 °C. Calculate the osmotic pressure of this solution at 35 °C, at which the solution density is 1.036 g/mL. The boiling point elevation constant is $k_b$ = 0.512 °C/m. The expected answer is $\Pi$ = 37.6 atm.
I tried it this way... |
I'll take a stab at this one, but I'm not a battery expert.
# What is a lithium "polymer" battery?
[Wikipedia](http://en.wikipedia.org/wiki/Lithium_polymer_battery) says that "lithium polymer battery" is now commonly used to refer to nearly any lithium ion battery that is encased in a flexible polymer shell instead... |
The boiling point of an aqueous solution containing sucrose, $\ce{C12H22O11}$, is $101.45~^\circ\mathrm{C}$. Calculate the osmotic pressure of this solution at $35~^\circ\mathrm{C}$, at which the solution density is $1.036~\mathrm{g/mL}$. The boiling point elevation constant is $k_b = 0.512~^\circ\mathrm{C\cdot m^{-1}}... |
How to calculate the osmotic pressure of a sucrose solution? |
> I did it in this step: First I use ΔTb=kbm And substitute following Tb=101.45 and kb=0.512 I get m=198.144 mol/kg
This should be the first clue that something went wrong. 198 mol of sucrose is about 67 ***kilograms*** of sucrose, so your implied molality means that for every kg of water, there are 67 kg of sucros... |
> Is there any set of principles in organic chemistry which govern as to
> which substances can be replaced with what?
Always be cautious about unwanted, side reactions that may occur. Proton exchanges are one huge class of possible side reactions. Protons transfers occur readily in many circumstances because the p... |
> Is there any set of principles in organic chemistry which govern as to
> which substances can be replaced with what?
Always be cautious about unwanted, side reactions that may occur. Proton exchanges are one huge class of possible side reactions. Protons transfers occur readily in many circumstances because the p... |
How to create a buffer solution from NaOH and CH3COOH? |
In my chemistry book, they say that an approach to making a buffer solution of $\mathrm{pH}=5.09$ is by adding an appropriate amount of strong base $(0.052\ \mathrm{mol}\ \ce{NaOH})$ to $0.300\ \mathrm{l}$ of $0.025\ \mathrm{mol/l}\ \ce{CH3COOH}$. But, I haven’t been able to figure out how they got those numbers. If I ... |
How to create a buffer solution from NaOH and CH₃COOH? |
A $52~g$ piece of iron at $250 °C$ is added to a mixture of $100~g$ of ice and $100~g$ of liquid water at thermal equilibrium ($0°C$). calculate the mass of ice that melts. (not all of the ice will melt, so you know the final temp of everything mixed together)
I think that the temperature of the mixture should stay ... |
A $52\ \mathrm{g}$ piece of iron at $250\ \mathrm{^\circ C}$ is added to a mixture of $100\ \mathrm{g}$ of ice and $100\ \mathrm{g}$ of liquid water at thermal equilibrium $(0\ \mathrm{^\circ C})$. Calculate the mass of ice that melts (not all of the ice will melt, so you know the final temp of everything mixed togethe... |
The Royal Institution seems to claim that they still possess some of Faraday's original gold colloids: <a href="http://www.rigb.org/our-history/iconic-objects/iconic-objects-list/faraday-gold-colloids">"These liquids are some of the first examples of metallic gold colloids, made by Michael Faraday over 150 years ago."<... |
Do Faraday's gold colloidal solutions still exist? |
The only reason for a short could be that by spraying a lot
of that can some moisture from air condensed due to the
refrigerating action of the spray.
But: Does the computer start again after some time has passed now?
Usually all supply voltages in Computers are short-Proof
and shut down on a short.
After d... |
This is a question in a problem sheet I have been set. Is it do do with the following equation: $\Lambda=\Lambda_0-a\sqrt c$? Surely charge density is proportional to concentration so therefore molar conductivity would decrease linearly with the square root of concentration (and $c$ $\alpha$ charge density?). Also, wha... |
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