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If one reads reviews on ceramic glazed cookware (esp. frying pans) one pattern becomes apparent: the pan is awesome at first, nothing sticks to it, even with little to no oil. Then, after a few months the non-stick properties more or less plummet and the pan may become worse than stainless steel pans.
As to why tha... |
What makes ceramic coated pans fail? Is it reversible? |
For hydrogen fuel cell to produce electricity, hydrogen will need to be supplied to the anode. To split oxygen and hydrogen from water and obtained hydrogen, we need to use electrolysis. To use electrolysis, we need to use a battery. My question is, why do we bother splitting up hydrogen and oxygen and then fed it int... |
The section you reference in Clayden is - IMO - not well written. The pyridinium ion, not pyridine, has a $\mathrm{p}K_\mathrm{a}$ of 5.5. Similarly it is the iminium ion, not the imine, that has a $\mathrm{p}K_\mathrm{a}$ around 9.
That said, let's move on to your question.
> Why is pyridine so much more acidi... |
Alkylation of acetone:
![enter image description here][1]
[1]: https://i.stack.imgur.com/quiP0.png
This reaction is done with a strong base (LDA in this case). Is this because the protons aren't particularly acidic? Secondly it should be done at low temperatures; why is this so? -78 degrees Celsius is typi... |
Why should alkylation of enols/carbonyl compounds be done at low temperature with a strong base? |
> Why should alkylation of enols/carbonyl compounds be done at low
> temperature with a strong base?
If you start with an unsymmetrical ketone, then there are two different sides of the molecule you could remove a proton from. Let's use methyl ethyl ketone as an example. Removing a proton from the methyl group lea... |
What is the product of this reaction?
There are two choices of benzylic protons (one proton on the carbon with the methyl group at the top of the cyclopentane, and two protons on the carbon in the cyclopentane at the bottom of the molecule).
I figure that the ketone ... |
For hydrogen fuel cell to produce electricity, hydrogen will need to be supplied to the anode. To split oxygen and hydrogen from water and obtain hydrogen, we need to use electrolysis. To use electrolysis, we need to use a battery.
My question is, why do we bother splitting up hydrogen and oxygen and then feed it i... |
Ins this video https://youtu.be/txk-VO1hzBY?t=2391 the speaker claims that **H2 + O2 -> H20** involves 23 reactions and 11 species. How do you list all of that ? |
How do you list all possible reactions and intermediates of a reaction? |
Ins this video https://youtu.be/txk-VO1hzBY?t=2391 the speaker claims that $$\ce{H2 + O2 -> H2O}$$ involves 23 reactions and 11 species. How do you list all of that ? |
What is the equation that demonstrate the relation between molar conductivity and temperature? |
Well I have to do research about the HPLC. It says, that because of the pressure the stationary phase can be made out of smaller particles and the pillars can be shorter. Also the seperation of the contents is supoosed to be superior, compared to other kinds of liquid chromatographies. Can somebody explain that to me? |
What does the pressure in the HPLC(High performance liquid chromatography) do? |
This is a practical question about the use of *rotary evaporators* ("rotovap"). So I'm asking for answers from people who actually use the things.
A rotovap typically uses a cold condenser to condense the solvent into a collection flask. But the distillation is typically done under weak vacuum as well. So the solven... |
I'm just starting OChem and I see that for a SN1 reaction, the rate of the reaction changes with the number of alkyl groups attached to the carbocation that is formed. The textbook (Klein) explains that this is due to the electron-donating nature of alkyl groups which helps to stabilize the carbocation. I was wondering... |
What happens to a molecule when it is unstable? |
Think of a [reaction-energy diagram](http://chemwiki.ucdavis.edu/Organic_Chemistry/Organic_Chemistry_With_a_Biological_Emphasis/Chapter_06%3A_Introduction_to_organic_reactivity_and_catalysis/Section_6.2%3A_Energy_diagrams). Specifically, think of a [two-step reaction energy diagram](http://chemwiki.ucdavis.edu/@api/de... |
If the absorbance of one of the buffer solutions (pH=4.623) was 0.319 and the absorbance of the basic solution was 0.625, what is the pKa of the indicator? Include activity coefficients in the calculations.
The correct answer is 4.927, but I don't know how to approach the problem to get the right answer. Thanks in adv... |
A task requires us to experiment water quality.
How would you reduce turbidity of a clay water sample with an effective and cost-effective method? |
For metal complexes with $A_{2}$ or $E$ ground state terms there is angular momentum contribution to the magnetic moment which is generally positive for more than half-filled subshells and negative otherwise, and related to the spin-only magnetic moment by
$$m_\mathrm{eff} = m_\mathrm{SO}\left(1-\frac{\alpha\lambda}{... |
Basic and acidic materials exist in nature, so it makes sense that our forefathers could know what happens when they react.
My questions are:
a. What are the earliest written accounts of acid-base reactions?
b. When were acid-base reactions intentionally used, e.g. for neutralizations or to create explosions? |
Basic and acidic materials exist in nature, so it makes sense that our forefathers could know what happens when they react. I would like to know when and how did they learn about this. In particular:
a. What is the earliest time in which people could witness acid-base reaction that causes fire or explosion (as in [t... |
>If the absorbance of one of the buffer solutions (pH=4.623) was 0.319 and the absorbance of the basic solution was 0.625, what is the $\mathrm{pK_a}$ of the indicator? Include activity coefficients in the calculations.
The correct answer is 4.927, but I don't know how to approach the problem to get the right answer... |
The following only gives some directions!
The molar extinction coefficient (molar absorptivity) is not necessary to correlate the absorbance and the concentration of the observed species, supposed that the same species is measured at one particular wavelength at different pH values!
Using the **Lambert-Beer Law**... |
While calculating the adiabatic flame temperature for the following combustion reaction:
$\Phi C_{2}H_{6} + 3.5(O_{2} + 3.76N_{2}) \rightarrow aCO_{2} + bCO + dH_{2}O + eH_{2} + fO_{2} + gN_{2}$
Where $\Phi$ is the equivalence ratio.
To determine the product composition ratios a,b,d,e,f I need to make mass bal... |
I have read that combining the DC current with a high frequency AC current, the electrolysis of water speeds up. Is this true? In that case, how is less energy wasted as heat? Or does it simply catalyze the process? |
What's the relationship between charge and acidity/basicity? |
There are van-der-Waals forces within non-polar molecules. I read it that is mainly due to the instantaneous movements of the electron cloud's distribution. When looking at symmetrical molecules like $\ce{CH4}$, the concept isn't hard to understand. But I have a question regarding the bioelectricity and action potentia... |
While calculating the adiabatic flame temperature for the following combustion reaction:
$$\ce{\Phi\, C2H6 + $3.5$\,(O2 + $3.76$\,N2) -> $a$\,CO2 + $b$\,CO + $d$\,H2O + $e$\,H2 + $f$\,O2 + $g$\,N2}$$
Where $\Phi$ is the equivalence ratio.
To determine the product composition ratios $a$, $b$, $d$, $e$, $f$ I ne... |
Which of the following product is formed in the reaction CH3MgBr in DryIce/acid ?
A) CH3COOH
B) CH4
C) CH3OH
D) CH3CH2CHO
My answer:
A since dry ice is CO2 and it has one carbon atom and reactant has one carbon, so in all the product should have 2 C atoms which is option A.
Am I correct? |
Which of the following product is formed in the reaction $\ce{CH3MgBr}$ in DryIce/acid ?
A) $\ce{CH3COOH}$
B) $\ce{CH4}$
C) $\ce{CH3OH}$
D) $\ce{CH3CH2CHO}$
My answer:
A), since dry ice is $\ce{CO2}$ and it has one carbon atom and reactant has one carbon, so in all the product should have 2 C... |
Why is pyridine so much more acidic than other similar imines (5.5 versus ~9, see picture)? Wouldn't delocalization of the positive charge into the aromatic system stabilize it and hence decrease acidity? Also the lone pair of pyridine is not delocalized into the perpendicular $\pi$-system and hence not any less availa... |
Benzamide can be converted to bezylamine using
A) $Br_2,KOH$
B) $PCl_5$
C) $LiAlH_4$
D) $NaBH_4$
My answer:
Reducing agent is used so C and D options both must be correct but since its single choice answer, I do not know which is more appropriate. Any help?
Also, what... |
Benzamide can be converted to bezylamine using
A) $\ce{Br2,\ KOH}$
B) $\ce{PCl5}$
C) $\ce{LiAlH4}$
D) $\ce{NaBH4}$
My answer:
Reducing agent is used so C and D options both must be correct but since its single choice answer, I do not know which is more appropriate. Any h... |
How to convert benzamide to benzylamine? |
Benzamide can be converted to benzylamine using
A) $\ce{Br2,\ KOH}$
B) $\ce{PCl5}$
C) $\ce{LiAlH4}$
D) $\ce{NaBH4}$
My answer:
Reducing agent is used so C and D options both must be correct but since its single choice answer, I do not know which is more appropriate. Any ... |
why some times 2nd shell onward it can hold 8 electrons and other times it is like they can hold K2 L8 M18 N32? when do i have to use first method(K2 L8 M8 N8) and when to use second method (k2 L8 M18)? I'm really confused. |
How many electrons does each shell hold? |
Differential Scanning Colorimetry (DSC) is a technique used to identify Polymorphism by revealing two melting points of a pure crystalline structure.
DSC shows a peak associated with the formation of the crystals. Hot Stage Microscopy (HSM) shows that only one of the polymorphs forms at the crystallisation temperat... |
Is Polymorphism accompanied with an energy change? |
Why is pyridine so much more acidic than other similar imines (5.5 versus ~9, see picture)? Wouldn't delocalization of the positive charge into the aromatic system stabilize it and hence decrease acidity? Also the lone pair of pyridine is not delocalized into the perpendicular $\pi$-system and hence not any less availa... |
I started to learn Chemistry with something like Hydrogen having 1 electron in the first shell, Oxygen having 2 electron in the first shell and 6 electron in the second shell... But I don't really understand how scientists know it? How do they know there are how many shells and how many electron per shell? Is that some... |
What is electrical conductivity of pool water?
I tried to search it, but without success. I need to know it for underwater electronic project.
Thanks
|
What is the electrical conductivity of pool water? I tried to find some information, unfortunately with no success. I need to know it to make an underwater electronic project.
Thanks
|
In [MnCl6]^2- , Mn has +4 oxidation state which gives it a 3d3 4s0 configuration. But how is it having 4 unpaired electrons ? |
Why [MnCl6]^2- has got 4 unpaired electrons instead of 3? |
>When do exceptions to this behaviour occur ? For example I have found that $\ce{Co(bipy)_{3}(ClO4)}$ has a lower experimental magnetic moment than the spin only formula predicts despite being a $\ce{Co(I)}$ (d8) compound with a $^{3}\!A_{2g}$ ground state, but I do not understand why.
According to ADVANCES IN INORG... |
Why [MnCl6]^2- has got 4 unpaired electrons instead of 3? |
I am reading a book that basically states what is the title.
This is something I observed when I was doing ICE: **when acid and base neutralize, we always assume complete neutralization.**
Interestingly, when we put acid in water, which can also be considered a Brønsted Lowery base, we called it ionization of acid, a... |
Why leveling effect is reduced when strong acid is dissolved in a weaker acid than water? |
In ${[MnCl_6]}^2_$ , Mn has +4 oxidation state which gives it a 3d3 4s0 configuration. But how is it having 4 unpaired electrons ? |
How do i go about answering this question? I'm confused and do not know where to start |
Why $[MnCl_6]^2_$has got 4 unpaired electrons instead of 3? |
In ${[MnCl_6]}^2-$ , Mn has +4 oxidation state which gives it a 3d3 4s0 configuration. But how is it having 4 unpaired electrons ? |
Why $[MnCl_6]^2-$ has got 4 unpaired electrons instead of 3? |
In ${[MnCl_6]}^{2-}$, $\ce{Mn}$ has +4 oxidation state which gives it a $\ce{3d^3}$ $\ce{4s^0}$ configuration. But how is it having 4 unpaired electrons? |
Why $[MnCl_6]^{2-}$ has got 4 unpaired electrons instead of 3? |
In $\ce{[MnCl_6]}^{2-}$, $\ce{Mn}$ has +4 oxidation state which gives it a $\ce{3d^3}$ $\ce{4s^0}$ configuration. But how is it having 4 unpaired electrons? |
Why [MnCl6]^2- has got 4 unpaired electrons instead of 3? |
> Is the following statement always true? The more −OH functional
> groups in the molecule, the more is its viscosity?
It's hard to find anything that is "always" true in chemistry, but I'd bet that within a series of molecules where the only variable is the number of $\ce{OH}$ groups, your statement is general... |
1. Start with the equation for the equilibrium constant
For a reaction $\ce{a\cdot A + b\cdot B <=> c\cdot C}$, the equilibrium constant $K_c$ is given as
\\[K_c = \mathrm{\frac{[C]^c}{[A]^a\cdot[B]^b}}\\]
2. Get familiar with the concept of **ICE** charts.
- Determine the concentrations of **A** and ... |
1. Start with the equation for the equilibrium constant
For a reaction $\ce{a\cdot A + b\cdot B <=> c\cdot C}$, the equilibrium constant $K_c$ is given as
\\[K_c = \mathrm{\frac{[C]^c}{[A]^a\cdot[B]^b}}\\]
2. Get familiar with the concept of **ICE** charts.
- Determine the concentrations of **A** and ... |
I am reading *The Selfish Gene* by Richard Dawkins.
I am on chapter two.
-----
He speaks of the observation of the formation of amino-acids when you simulate environmental conditions of primordial earth.
`UV light + water + carbon dioxide + methane + ammonia + a couple of weeks time = amino-acids`
I u... |
I am reading *The Selfish Gene* by Richard Dawkins.
I am on chapter two.
-----
He speaks of the observation of the formation of amino-acids when you simulate environmental conditions of primordial earth.
`UV light + water + carbon dioxide + methane + ammonia + a couple of weeks time = amino-acids`
I u... |
I am reading *The Selfish Gene* by Richard Dawkins.
I am on chapter two.
-----
He speaks of the observation of the formation of amino-acids when you simulate environmental conditions of primordial earth.
`UV light + water + carbon dioxide + methane + ammonia + a couple of weeks time = amino-acids`
I u... |
I believe these are all aromatic, as they all follow Huckel's rule of 4n+2 pi electrons. Is the last molecule also aromatic?
 |
Are these aromatic? |
Today, I'm looking for how to find the 2nd perturbation to the base in Rayleigh Schrödinger Perturbation Theory (RSPT).
**SETUP**
Starting from the 2nd order perturbation:
\begin{equation}
\hat{H}^0 |n^2\rangle + \hat{V} |n^1\rangle = E_n^0 |n^2\rangle + E_n^1 |n^1\rangle + E_n^2 |n^0\rangle
\end{equa... |
How to find 2nd order pertubation to wave function? |
For my chemistry lab we had to heat sodium chloride and there was a colour change and a sizzling sound. Is it a decomposition or synthesis reaction, and what is the balanced chemical equation for it? |
Whats the Balanced chemical equation for heating sodium chloride and what type of a reaction is it? |
> 1. We have observed that the chemical conditions outlined at the top of this question seem to yield more complex organic compounds with time.
> Do we know (or have theories) as to why this is, or is it merely
> something we have observed and re-created.
A recurring theme in chemistry,and all of your questions, i... |
Can covalently bonded hydrocarbons be influenced by a magnetic field? |
> 1. We have observed that the chemical conditions outlined at the top of this question seem to yield more complex organic compounds with time.
> Do we know (or have theories) as to why this is, or is it merely
> something we have observed and re-created.
A recurring theme in chemistry,and all of your questions, i... |
Just because there are no unpaired electrons doesn't mean magnetic fields can't influence something. Unpaired electrons tend to lead to *strong* interactions with magnetic fields (the dioxygen in air has two and is paramagnetic, an effect best seen in the liquid phase where a magnet will attract the cold liquid).
Bu... |
We heated rock salt for a chemistry lab and it changed from white crystally rock to brown rock and ash-like materiak on the bottom of the test tube. Also there was a sizzling\popping noise. Why did it change colour and why was there a noise? What caused this? |
I can think of any other way to influence the value of $\Delta G$ than (1) change the temperature (2) providing an external source to overcome the negative cell potential
The relationship between $\Delta G$ and $E_{cell}$ is **$\Delta G =-nFE_{cell}$**
Between $\Delta H$, $\Delta S$ and $\Delta G$ is **$\Delta G=\Del... |
I've been dealing with assigning stereochemistry and I seem to be doing okay, but I've come across a molecule that I've found a little tricky to deal with.
I've identified three stereocentres, highlighted below. My first question would be to confir... |
I'm trying to solve this problem:
Specifically, how does one know which nitrogen is more basic? I'm assuming that for the first molecule, that it's the nitrogen without the proton, since it seems like the other nitrogen has already been protonated (and already has acted... |
How does one determine the relative basicity of a nitrogen in a molecule? |
I was asked to " Use VSEPR theory to predict the most stable structure for SF3Cl and justify your answer. "
I managed to interpret the structure as seesaw and with a lone pair on the equatorial position. However, I had chosen that the most stable structure was that with Chlorine on the equatorial position because I ... |
So if we have an alpha halogen ketone, why is an Sn1 type mechanism so unfavorable for that species?
I don't understand. It seems like the C+ would be resonance stabilized by the carbonyl's double bond. |
Why are alpha-carbonyl relatively less stable? |
Use a combination of
- the *exclusion principle*: sort out the unlikely centres with low electron density and
- paper work to figure out those nitrogen atoms for which the additional positive charge can be distributed over a larger part of the molecule without moving the proton.
![enter image description... |
I need help to determine the structure of unknown compound from my 1H NMR , 13C nmr and dept 135 spectrum? <br/>
I am a student and in my organic chemistry class we each had an unknown chemical from natural product. It dissolves in water.
On the bottom of the H NMR sheet it says:
>Label --- Assigned Value --- F... |
According to present definition torr and mm of Hg differ though slightly.
I am still confused over it. Can someone write an explicit answer differentiating between them and the reason for differentiation as earlier they were considered same. The explanation is probably related to the changes is pressure at different h... |
My son and daughter got given gifts where you place a plastic egg in water, and the (rubber?) toy inside expands (over three days) and breaks the shell of the egg so it 'hatches'.
![enter image description here][1]![enter image description here][2]
I also observed that three weeks later the toys shrank again, ... |
What is the reaction in a child's 'add water and watch the egg hatch' toy? |
What is the difference between the units 'torr' and 'mm of Hg'? |
I recently heard that during some period of time Purina pet food was being produced from crude oil via a set of complex chemical transformations. Which, I think, is mostly bluff and marketing. So is it possible, and have somebody had any real positive practical experience of getting amino acids from hydrocarbons? |
Is it possible to synthesize amino acids from hydrocarbons? |
The product of an aldol reaction is a $\beta$-hydroxy ketone. This can go on to eliminate to form an alkene thus:
![enter image description here][1]
[1]: https://i.stack.imgur.com/alKG4.png
However, the species on the far left of the above diagram (the $\beta$-hydroxy ketone product of the first aldol reac... |
What determines whether an aldol reaction will occur again or eliminate? |
Why do some chemical symbols contain a single alphabet while others contain double alphabets? |
Why do some chemical symbols contain a single letter while others contain two letters in the periodic table? |
> 1. We have observed that the chemical conditions outlined at the top of this question seem to yield more complex organic compounds with time.
> Do we know (or have theories) as to why this is, or is it merely
> something we have observed and re-created.
A recurring theme in chemistry,and all of your questions, i... |
I was asked to " Use VSEPR theory to predict the most stable structure for $\ce{SF3Cl}$ and justify your answer. "
I managed to interpret the structure as seesaw and with a lone pair on the equatorial position. However, I had chosen that the most stable structure was that with Chlorine on the equatorial position bec... |
My problem sheet asks me: " Draw a mechanism for the formation of $EtCH_2COOH$ from the reaction of $MeCOCH(Et)COOEt$ with $NaOH$ in $EtOH$"
This has got me stumped. The mechanisms that I have attempted use the hydroxide ion as the base/nucleophile, is this right? My initial thoughts were to make the enolate by depr... |
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