instruction stringlengths 15 21.8k |
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I am curious as to why **ester** is used often as a solvent in organic chemistry? How is it different that just using water, which is also polar? I'm sorry if this is a basic question, I'm just a student. |
If $125$ Calories of heat is applied to $60.0\text{g}$ piece of copper at $21.0^\circ\text{C}$, what will the final temperature be? The specific head of copper is $0.0920 \text{ cal/gC}$.
All I have to answer this question is a formula:
$SH = \text{heat/(mass}\times \Delta T)$
|
The SN1 solvolysis of one of the following alkenyl bromides is in MeOH approximately 100000
times faster than the other one. Which is the more reactive one? Draw the mechanism including the transition state, determine the rate determining step and draw the reaction product of each compound.![enter image description h... |
> I know potassium dichromate is a strong oxidizing agent
You have already identified one partner and its role in a redox reaction. Good start!
So which component will be oxidized to what?
Can we assume that the reaction is carried out in water? If so, let's have a look at the ions in solution.
We'll have $... |
> [...] SN1 solvolysis [...]
Let's recall what we know about these. We have a two-step reaction, consisting of
1. heterolysis of the starting material
2. association of a nucleophile $\ce{Nu}$
We remember that the heterolysis is not assisted by $\ce{Nu}$, there is no backside attack of $\ce{Nu}$, pushing out... |
> [...] SN1 solvolysis [...]
Let's recall what we know about these. We have a two-step reaction, consisting of
1. heterolysis of the starting material
2. association of a nucleophile $\ce{Nu}$
We remember that the heterolysis is not assisted by $\ce{Nu}$, there is no backside attack of $\ce{Nu}$, pushing out... |
----------
Both processes involved the denaturation of proteins and complex reactions so is impossible reverse them **only** with a change of temperature.
----------
#Boiling an Egg
Although in most case denaturation is not reversible there are some cases where it is.
However in the case of Egg whi... |
What are hybridisation states of each carbon atom in the following compounds?
CH2=C=O, CH3CH=CH2, (CH3)2CO, CH2=CHCN, C6H6. |
Method to find out Hybridization of a molecule? |
What are hybridisation states of each carbon atom in the following compounds?
$\ce{CH2=C=O, CH3CH=CH2, (CH3)2CO, CH2=CHCN, C6H6}$. |
What is hyper-conjugation and how do you know if there is hyper-conjugation in a compound and which orbitals are involved in hyper-conjugation? |
You're on the right track.
<hr>
\\begin{eqnarray}
Q & = & m\cdot c\cdot \Delta T\\\
\mathbf{unit\ analysis} \qquad \textrm{kJ} & = & \textrm{kg}\cdot \frac{\textrm{kJ}}{\textrm{kg} \cdot \textrm{K}} \cdot \textrm{K}
\\end{eqnarray}
<hr>
For water, the specific heat capacity $c = 4.18 \large{\frac{\textrm{kJ}}{\t... |
I think it should be acid, as I am aware that a compound by the name of Boric acid exists. But how can the oxide be acidic when it is electropositive? Also, other members of its group are well known metals. Why isn't the oxide amphoteric, when its group member Aluminium has an amphoteric oxide?
My teacher told us t... |
What is the nature of the oxide of boron? |
Does anyone know where I can find the reaction rate coefficient and design equation for the electrolysis of brine and sodium hydroxide solution? |
I'm trying to draw the state correlation diagram for the reaction of *cyclopent-2-enyl anion* to *pentadienyl anion* but I don't know which symmetry element is preserved in this reaction. What could it be? |
Symmetry element in the coversion of cyclopent-2-enyl anion to pentadienyl anion? |
Why does plutonium have more oxidation states than samarium?
Electron configuration of Pu: $\ce{[Rn] 5f^6 7s^2}$
Electron configuration of Sm: $\ce{[Xe] 4f^6 6s^2}$
I thought that only the valence electrons affected the oxidation states, so why does plutonium have more oxidation states (6,5,4,3) than samarium ... |
In addition to some material I linked in comments, [this article][1] from Eric Scerri's blog (a chemist who focuses on aspects of periodicity, including electronic distribution) states (regarding the electronic configuration of scandium compared to calcium and to the Sc³⁺ ion):
>This amounts to saying that all three... |
The relative energies of the electronic subshells [has been calculated for atoms in the vicinity of $Z=20$](http://pubs.acs.org/doi/abs/10.1021/ed071p469), and the result is surprising:
![Transition Metals and the Aufbau Principle, fig. 1][1]
Looking at this graph, by all means the electronic configuration of sca... |
The relative energies of the electronic subshells [has been calculated for atoms in the vicinity of $Z=20$](http://pubs.acs.org/doi/abs/10.1021/ed071p469), and the result is surprising:
![Transition Metals and the Aufbau Principle, fig. 1][1]
Looking at this graph, by all means the electronic configuration of sca... |
The relative energies of the electronic subshells [has been calculated for atoms in the vicinity of $Z=20$](http://pubs.acs.org/doi/abs/10.1021/ed071p469), and the result is surprising:
![Transition Metals and the Aufbau Principle, fig. 1][1]
Looking at this graph, by all means the electronic configuration of sca... |
I am trying to figure out the shape of the iodate ion or $\ce{IO3^-}$. No matter how many times I draw it, I keep getting Iodine in the centre, and 3 oxygen atoms surrounding it, 2 with single bonds, and 1 with a double bond. This would make it a trigonal planar shape. It would mean that it is not a "bent" shape.
I ... |
Iodate ion (IO3-). Is it polar or non-polar? |
I was working on my homework which was to write a description of what would occur if zinc and sulfur reacted and what steps would a scientist have to make in order to make them react. When I researched I bit, I saw that it would be a exothermic reaction, and I wanted to show this by using enthalpy. I haven't been taugh... |
I was working on my homework which was to write a description of what would occur if zinc and sulfur reacted and what steps would a scientist have to make in order to make them react. When I researched I bit, I saw that it would be a exothermic reaction, and I wanted to show this by using enthalpy. I haven't been taugh... |
I was working on my homework which was to write a description of what would occur if zinc and sulfur reacted and what steps would a scientist have to make in order to make them react. When I researched I bit, [I saw that it would be a exothermic reaction][1], and I wanted to show this by [using enthalpy][2]. I haven't ... |
Nice! You've brought everything you need.
If you can't identify your electrophile immendiately, do it the other way around: Assign function to all components. The one that is left must be your electrophile - or its precursor.
Do you remember the role of $\ce{AlCl3}$ in electrophilic aromatic substitutions? Where ... |
Nice! You've brought everything you need.
If you can't identify your electrophile immediately, do it the other way around: Assign function to all components. The one that is left must be your electrophile - or its precursor.
Do you remember the role of $\ce{AlCl3}$ in electrophilic aromatic substitutions? Where c... |
**Summary** :
I am currently testing how a certain type of foam adsorbs HAP, PCB and OCP, and to this end I am depositing some on the foam, then extracting it. To know how much was extracted, I need to compare with a standard solution of HAP, PCB and OCP. The problem is that when I look at the chromatograms, the extra... |
Standard solution and extracted solution : same concentration? |
I see no difference between the two,both say that degree of adsorption reaches a limiting value at high pressures and at very low pressures degree of adsorption is directly propotional to pressure.
Where does the difference lie? |
Nice! You've brought everything you need.
If you can't identify your electrophile immediately, do it the other way around: Assign function to all components. The one that is left must be your electrophile - or its precursor.
Do you remember the role of $\ce{AlCl3}$ in electrophilic aromatic substitutions? Where c... |
Thank you all for participating. So, the smoothness arises from mainly two factors:
* Molecules have a wide range of energy levels due to bond stretching / vibration etc. that partially absorb the photon energy. Atomic atoms do not have such energy levels so their AAS spectra are spiky.
* The measurement technolo... |
**Summary** :
I am currently testing how a certain type of foam adsorbs HAP, PCB and OCP, and to this end I am depositing some on the foam, then extracting it. To know how much was extracted, I need to compare with a standard solution of HAP, PCB and OCP. The problem is that when I look at the chromatograms, the extra... |
The free energies of formation of the elements in their standard states is zero, by definition. You can look up the (variously reported) standard enthalpy of formation of the product, −204.6 kJ/mol (exothermic!). It is roughly the binding energy of the crystal lattice less the ionization energies of the inputs. So, ... |
Why does anything dissolve at all? The binding energy (lattice energy) of the solid must be compensated by solvation energy and entropy of the solution. Like dissolves like (then cheats, like clathrates and micelles). As the solution concentrates, incremental driving energies diminish.
Don't think about adding wa... |
Would the reaction between Zinc and sulfur be...?
Zn(s) + S(s) --> Zns(s)
OR
8 Zn(s) + S_8(s) --> 8ZnS
I know that S and S_8 are allotropes of sulfur, but which one should I use for a reaction with sulfur at room temperature. |
Would the reaction between zinc and sulfur be
$$\ce{Zn_{(s)} + S_{(s)} -> ZnS_{(s)}}$$
or
$$\ce{8 Zn_{(s)} + S_8\ _{(s)} -> 8ZnS_{(s)}}$$
I know that $\ce{S}$ and $\ce{S8}$ are allotropes of sulfur, but which one should I use for a reaction with sulfur at room temperature? |
Crystalline sulfur, at room temperature, exists only as $\ce{S8}$.
So basically, that's the only option you have.
Breaking down $\ce{S8}$ chains is doable but over 160°C, followed by polymerization.
At 200°C, polymer chains start to break.
Back to your question, $\ce{S8}$ is the most stable form for sulfur ... |
What is the nature of the bonds between P and O in oxoacids of phosphorous?
Is it a double bond or coordinate bond?
Wikipedia says that it is "double bond" but many times I encountered "coordinate bond". |
Today I finally mustered the courage to go and talk to the director of the labs to politely ask him if I could use the labs out of class hours. Long story short, our lab sessions "are bad" because we are given a protocol, and like babies we just need to follow it. No brainer, and I am against that. So I got permission ... |
Does periodic acid cleave trans-cyclopropane-1,2-diol, trans-cyclobutane-1,2-diol and trans-cyclopentane-1,2-diol? |
We know that the $\ce C$ atom in acetylene ($\ce {H-C\bond{#}C-H}$) is $sp$ hybridised and so is more electronegative than alkenes or alkanes. This electronegativity makes the $\ce H$ an acidic one.
So, why doesn't it react with strong bases like $\ce {NaOH}$ and $\ce{KOH}$? |
Why does acetylene, having acidic proton, not react with strong bases like $\ce {NaOH}$ and $\ce {KOH}$? |
I've read in some book that one of the old chemists was able to transform cheap metals into gold.
I know that gold is an element (Au) so we can't transform a metal into Au. But as I read further it says that the chemist doesn't actually transform metals into gold but into something very similar to gold (similar phys... |
Can we goldify metals? |
What are the main differences of CTAB and DTAB surfactants? And what are practical applications of them? |
CTAB: http://www.sigmaaldrich.com/catalog/product/fluka/52369?lang=en®ion=US
aka Hexadecyltrimethylammonium bromide
DTAB: http://www.sigmaaldrich.com/catalog/product/sigma/d8638?lang=en®ion=US
aka Dodecyltrimethylammonium bromide
Sort of a vague question, don't know where to start. To begin, CTAB has a hydr... |
CTAB: http://www.sigmaaldrich.com/catalog/product/fluka/52369?lang=en®ion=US
aka Hexadecyltrimethylammonium bromide
DTAB: http://www.sigmaaldrich.com/catalog/product/sigma/d8638?lang=en®ion=US
aka Dodecyltrimethylammonium bromide
Sort of a vague question, don't know where to start. To begin, CTAB has a hydr... |
CTAB, aka [Hexadecyltrimethylammonium bromide](http://www.sigmaaldrich.com/catalog/product/fluka/52369?lang=en®ion=US)
DTAB, aka [Dodecyltrimethylammonium bromide][1]
Sort of a vague question, don't know where to start. To begin, CTAB has a hydrocarbon chain length of 16 (as its name suggests) whereas DTAB has... |
It won't decide the issue but the [Organic Chemistry][1] text by Clayden, Greeves, Warren and Wothers also mentions that the matter is not as clear-cut as the majority of your text books make it seem. This might strengthen the position of the textbook you're using a bit. But again, there are no references given. Here i... |
It won't decide the issue but the [Organic Chemistry][1] text by Clayden, Greeves, Warren and Wothers also mentions that the matter might not be as clear-cut as the majority of your textbooks make it seem. This might strengthen the position of the textbook you're using a bit. But again, there are no references given. H... |
It won't decide the issue but the [Organic Chemistry][1] text by Clayden, Greeves, Warren and Wothers also mentions that the matter might not be as clear-cut as the majority of your textbooks make it seem. This might strengthen the position of the textbook you're using a bit. But again, there are no references given. H... |
## First part ##
It won't decide the issue but the [Organic Chemistry][1] text by Clayden, Greeves, Warren and Wothers also mentions that the matter might not be as clear-cut as the majority of your textbooks make it seem. This might strengthen the position of the textbook you're using a bit. But again, there are no... |
## First part ##
It won't decide the issue but the [Organic Chemistry][1] text by Clayden, Greeves, Warren and Wothers also mentions that the matter might not be as clear-cut as the majority of your textbooks make it seem. This might strengthen the position of the textbook you're using a bit. But again, there are no... |
It seems that you would need information about how much of each reactant you have when conducting this. As you may have already thought, "Not Enough Info" seems like a good answer. Why not just pick that?
Even if the stoichiometric ratio between two reactants A & B is 1:99999, or 99999:1, if you have no B to start ... |
No alchemist can perform transmutation of lead into gold with alembic! But now day we can perform [nuclear transmutation](http://en.wikipedia.org/wiki/Nuclear_transmutation) and gold can be now synthesized by irradiation of mercury or platinum in a nuclear reactor or with an accelerator. However this is not cost effe... |
Black tea served hot can be quite bitter (presumably high pH).
Several people I have known will add a single grain of salt to the black tea - which reduces the perceived bitterness.
My question is: **What is the reason a grain of salt alters the perceived bitterness of black tea by such a high degree?** Can y... |
What is the reason a grain of salt alters the perceived bitterness of black tea by such a high degree? |
Im doing a project for lead (II) sulfide quantum dots because they have optical transitions in the near infrared. I understand the simple particle in a box approach where confinement strengthens exponentially when the box shrinks. What I don't get how this confinement results in discrete energy levels specifically. Can... |
I'm writing a computer program to calculate the order of a chemical reaction with respect to each reactant. When I do this by hand, it's easy to isolate which reactant concentration stays relatively the same while the others change. However, when you don't have an isolation method available, is there a non-guess and ch... |
A hydrogen atom is in cubical box with side lengths equal to 100 Å. For what value of n (principal quantum number) will the expectation value of the radius equal to one-half the box size? |
Quantum Chemistry: For what value of n (principal quantum number) will the expectation value of the radius equal to one-half of a 100 Å box size? |
How alkanes can be prepared by aldehydes and ketones? |
I had a recent question on a test that asked what the products would be if Sodium Hydrogen Carbonate were dissolved in water. I had a few candidate answers
1. $\ce{NaHCO3}\rightarrow \ce{Na+}+\ce{HCO3-}$, but that one doesn't involve water at all
2. $\ce{NaHCO3}+\ce{H2O}\rightarrow\ce{Na+}+\ce{OH-}+\ce{H2CO3}$, b... |
You want to deoxygenate the carbonyls under conditions where you do not get condensation reactions. Do you want to pull the oxygen or dimerize to the olefins then hydrogenate?
Wolff-Kishner or Clemmensen reductions, thioacetal then Raney nickel and hydrogen. McMurry reaction for dimerization. Given polymethylhydr... |
At school we've learned about calculating the voltage needed to perform a electrolysis. The ampere is how many electrons passes per time. The formula is given $I = \frac{V}{R}$
This means that given an electrolysis with $4.0V$ we get $I = \frac{4.0}{R}$.
If I am correct what would decide how fast the electrolysis... |
How does voltage and resistance affect an electrolysis? |
Voltage determines the kind of chemistry at each electrode. Gold is purified by plating the anode to the cathode at minimum voltage for the half-reaction, so impurities either do not dissolve and do not plate out. Copper electrorefining electrode mud contains valuable trace elements in concentrated from.
Current d... |
Coffee served hot can be [quite bitter][1] (presumably high pH).
Several people I have known will add a single grain of [salt to the coffee][2] - which [reduces the perceived bitterness][3].
My question is: **What is the reason a grain of salt alters the perceived bitterness of coffee by such a high degree?**... |
What is the reason a grain of salt alters the perceived bitterness of coffee by such a high degree? |
To make $\text{NaOH}$ one could electrolyze a solution of $\text{NaCl}$ in water ($\text{H}_2\text{O}$) It would go like this:
$2H_2O (l) + 2Cl^-(aq) + 2Na^+(aq) \to H^2(g) + Cl^2(g) + Na^+(aq) + 2OH^-(aq)$
After calculating a bit, I found that even just a few minutes of electrolyzing this at $10A$ could be dea... |
To make $\ce{NaOH}$ one could electrolyze a solution of $\ce{NaCl}$ in water ($\ce{H2O}$) It would go like this:
$\ce{2H2O (l) + 2Cl^- (aq) + 2Na^+(aq) -> H2(g) + Cl2(g) + Na^+(aq) + 2OH^-(aq)}$
After calculating a bit, I found that even just a few minutes of electrolyzing this at $10A$ could be deadly.
Can ... |
Is there a danger in electrolyzing NaCl? |
I've read several places that when electrolyzing water into $O_2$ and $H_2$ adding a salt or an acid will speed up the process. Why is this? |
Why does adding an acid speed up electrolysis of water? |
I want to electrolyze water to get oxygen and hydrogen. I want to mix them in a regular balloon (15-20 liters) and ignite it. How much hydrogen would you need in a 2:1 ratio with air for it to be dangerous? Is this generally a safe experiment? |
How explosive is hydrogen gas? |
I've read in several places that when electrolyzing water into $\ce{O2}$ and $\ce{H2}$, that adding a salt or an acid will speed up the process. Why is this? |
I want to electrolyze water to get oxygen and hydrogen. I want to mix them in a regular balloon and ignite it. How much hydrogen would you need in a 2:1 ratio with air for it to be dangerous? Is this generally a safe experiment? |
Is not so intuitive as it seems and your questions are all legitimate questions.
But I think sometimes even good argumentations can't be used as evidences chemistry. So we can start looking point by point yours.
----------
#$\ce{NaHCO3}\rightarrow \ce{Na+}+\ce{HCO3-}$, but that one doesn't involve water at al... |
In Electrophilic Aromatic Substitution ($\text{S}_{\text{E}}\text{Ar}$) reactions groups that can donate an electron pair into the aromatic ring, e.g. $\ce{-OH}$ or $\ce{-NH2}$, are ortho-/para-directing.
<img src="https://i.stack.imgur.com/66MCG.png" height="150">
In the case of $\ce{-NH2}$-groups one has to be ... |
Electrophilic Aromatic Substitution: Are protonated OH-groups ortho-/para-directing? |
In Electrophilic Aromatic Substitution ($\text{S}_{\text{E}}\text{Ar}$) reactions groups that can donate an electron pair into the aromatic ring, e.g. $\ce{-OH}$ or $\ce{-NH2}$, are *ortho*-/*para*-directing.
<img src="https://i.stack.imgur.com/66MCG.png" height="150">
In the case of $\ce{-NH2}$-groups one has to... |
Electrophilic Aromatic Substitution: Are protonated OH-groups ortho-/para- or meta-directing? |
I'm told the `KMnO4` is a strong electrolyte.
How can I figure out how the reaction looks like? |
How to determine the reaction of a strong electrolyte? |
In Electrophilic Aromatic Substitution ($\text{S}_{\text{E}}\text{Ar}$) reactions groups that can donate an electron pair into the aromatic ring, e.g. $\ce{-OH}$ or $\ce{-NH2}$, are *ortho*-/*para*-directing.
<img src="https://i.stack.imgur.com/66MCG.png" height="150">
In the case of $\ce{-NH2}$-groups one has to... |
What sort of ideal conditions are required - theoretically - to conduct polymerization reactions to make all the macromolecules end up with exactly the same molecular mass, just like the products in normal chemical reactions? How do living organisms manage to synthesize macromolecules, for instance proteins, different ... |
Polymers with no molecular mass distribution? |
I'm told the $\ce{KMnO4}$ is a strong electrolyte.
How can I figure out how the reaction looks like? |
In Electrophilic Aromatic Substitution ($\text{S}_{\text{E}}\text{Ar}$) reactions groups that can donate an electron pair into the aromatic ring, e.g. $\ce{-OH}$ or $\ce{-NH2}$, are *ortho*-/*para*-directing.
<img src="https://i.stack.imgur.com/66MCG.png" height="150">
In the case of $\ce{-NH2}$-groups one has to... |
In Electrophilic Aromatic Substitution ($\text{S}_{\text{E}}\text{Ar}$) reactions groups that can donate an electron pair into the aromatic ring, e.g. $\ce{-OH}$ or $\ce{-NH2}$, are *ortho*-/*para*-directing.
<img src="https://i.stack.imgur.com/66MCG.png" height="150">
In the case of $\ce{-NH2}$-groups one has to... |
I think your question implicates another question (which is also mentioned in some comments here), namely: Why are all energy eigenvalues of states with a different **angular momentum quantum number** $\ell$ but with the same **principal quantum number** $n$ (e.g. $3s$, $3p$, $3d$) degenerate in the hydrogen atom but n... |
In Electrophilic Aromatic Substitution ($\text{S}_{\text{E}}\text{Ar}$) reactions groups that can donate an electron pair into the aromatic ring, e.g. $\ce{-OH}$ or $\ce{-NH2}$, are *ortho*-/*para*-directing.
<img src="https://i.stack.imgur.com/66MCG.png" height="150">
In the case of $\ce{-NH2}$-groups one has to... |
In case FriendofKim can still read this...
First, let me say that I've enjoyed many times exploding soap bubbles of about **one milliliter** filled with hydrolysis gas. That is 1 cubic centimeter.
That will give you a sound that rings in your ears in a decent sized living room. You may wish to use ear protection ... |
I am trying to find out what BPA is used for in the industrial production of plastics. On sources such as Wikipedia I only found the information that it is used, but not why.
What are the advantages in using BPA in the production of plastics? Why is it needed? |
What is Bisphenol A used for? |
![enter image description here][1]
[1]: https://i.stack.imgur.com/UN7B2.jpg
Hi, Just have a basic question on a closed manometer :
So I do understand the basic idea behind manometers. I see that in this case the pressure of gas is lower than that of the liquid, which is why the liquid is higher on the left... |
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