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I know how to get the equation from the Clapeyron equation but I have a question regarding a the integration along a phase boundary and a small step in the derivation that I will make clear when I reach that step. Firstly, the Clapeyron equation:
$$\frac{\mathrm{d}p}{\mathrm{d}T}=\frac{\Delta S}{\Delta V}$$
Or al... |
Can we picture metallic bonding as an equilibrium between electrons and cations?
Suppose:
>$$\ce{Al}^{3+} + 3\ce{e}^{-} \rightleftharpoons \ce{Al}$$
|
Can we picture metallic bonding as an equilibrium between electrons and cations? |
Are you familiar with ligand field stabilisation energy? This approach answers your question. Interaction of the central metal ion with the surrounding ligands causes splitting of the d orbitals into an essentially upper and lower energy level, the form of the splitting is rather complex and depends directly upon the s... |
For solid-liquid mixtures, cooling crystallization process can be used to separate the solute substances from each other. Assume that we have two salts that have very close solubility in a certain solvent which we are going to use. First, we dissolve the salts in the solvent while heating. After a point, we let the mix... |
Are you familiar with ligand field stabilisation energy? This approach answers your question. Interaction of the central metal ion with the surrounding ligands causes splitting of the d orbitals into an essentially upper and lower energy level, the form of the splitting is rather complex and depends directly upon the s... |
I have noticed that liquid $\ce{O2}$ (I clarify it as $\ce{O2}$ because oxygen exists in several other forms which have different colors in the liquid state than $\ce{O2}$) has a light blue color to it.
![liquid oxygen][1]
[1]: https://i.stack.imgur.com/NW9kM.jpg
In the solid state it has a light blue colo... |
The zinc ion in its +2 state can show no more pairing, since all the electrons are already paired - so in any complex it forms it will have the same magnetic moment as it does right now. $\ce{Ti}$ in its +3 state will show both outer and inner orbital complexes without any electrons pairing.
So while calling these ... |
Can we picture metallic bonding as an equilibrium between electrons and cations?
Suppose:
>$$\ce{Al^3+ + 3e- <=> Al}$$
|
Are you familiar with ligand field stabilisation energy? This approach answers your question. Interaction of the central metal ion with the surrounding ligands causes splitting of the $d$ orbitals into an essentially upper and lower energy level, the form of the splitting is rather complex and depends directly upon the... |
Heyo, I am having a problem with this equation for redox potentials
> $\Delta G=-nF\Delta E$
In this equation I never am totally sure about what the value of n should be, for example for the reaction shown below, would the n be 2 electrons or 1 electron? Personally, I think it should be 2 electrons because that i... |
What mechanisms might make a substance travel different distances on the same TLC plate? |
Heyo, I am having a problem with this equation for redox potentials
> $\Delta G=-nF\Delta E$
In this equation I never am totally sure about what the value of n should be, for example for the reaction shown below, would the n be 2 electrons or 1 electron? Personally, I think it should be 2 electrons because that i... |
A half-cell consisting of palladium rod dipping into a $1\ M$ $\ce{Pd(NO_3)_2}$ solution is connected with a standard hydrogen half-cell. The cell voltage is $0.99\ volt$ and the platinum electrode in the hydrogen half-cell is the anode. Determine $E^ο$ for the reaction $\ce{Pd\longrightarrow Pd^{2+} + 2e}$.
Now the... |
Sorry if this is an outright stupid question. I am no chemist.
For nitric oxide:
$\ce{2{NH_{3}} + 2 NO -> 2 {N_{2}} + {H_{2}} + 2{H_{2}O}}$
For nitrogen dioxide:
$\ce{2{NH_{3}} + 2{NO_{2}} -> 2{N_{2}} + {H_{2}} + 2{H_{2}O} + {O_{2}}}$
or
$\ce{4{NH_{3}} + 2{NO_{2}} -> 3{N_{2}} + 2{H_{2}} + 4{H_{2}O}}$
... |
I am having a problem with this equation for redox potentials
> $\Delta G=-nF\Delta E$
In this equation I never am totally sure about what the value of n should be, for example for the reaction shown below, would the n be 2 electrons or 1 electron? Personally, I think it should be 2 electrons because that is the ... |
In the awwa notebook for Na2SiF6 determination, why it is required to wash the product sample in an alcoholised KCl solution before titration? |
Why wash a sample before titration? |
In the awwa notebook for $\ce{Na2SiF6}$ determination, why it is required to wash the product sample in an alcoholised $\ce{KCl}$ solution before titration? |
I am having a problem with this equation for redox potentials
> $\Delta G=-nF\Delta E$
In this equation I never am totally sure about what the value of ***n*** should be, for example for the reaction shown below, would the ***n*** be 2 electrons or 1 electron? Personally, I think it should be 2 electrons because ... |
Why is it that energy is released from electrons when they move from one atom to a more electronegative one? |
I'm calculating the multipole moments on several fragments of a molecule. What are some procedures to ensure that the charges etc are representative of the complete molecule? also, I'm not getting an overall charge in a neutral molecule |
I'm calculating the multipole moments on several fragments of a molecule. What are some procedures to ensure that the charges etc are representative of the complete molecule? How do I ensure I'm not getting an overall charge in a neutral molecule? |
Why is energy released as electrons move? |
In my book it is given that earlier cylinder were filled with 2% oxygen and 98% helium. Nowadays it is filled with 11.7% helium, 56.2% nitrogen and 32.1% oxygen.
There are few questions which come up in my mind
- Earlier 2% oxygen is changed to 32%. So was 2% oxygen enough for huaman?
- 98% helium is reduce... |
I am having a problem with this equation for redox potentials
> $\Delta G=-nF\Delta E$
In this equation I never am totally sure about what the value of ***n*** should be, for example for the reaction shown below, would the ***n*** be 2 electrons or 1 electron? Personally, I think it should be 2 electrons because ... |
Is there a difference between hydrated oxides and hydroxides? |
In 1955, was proposed from some scientists that hollow cathode lamp is a good source to emitt a monochromatic radiation ( which is of course a part of the spectrometer ). But then i read that **continuum radiation is not preffered in AAS**, can anyone give any clear reason why it isn't ? |
When a liquid (in my case I used butane) under high pressure is released into the air, it becomes gaseous, and the container seems to get colder. Why is it that turning a liquid to a gas requires energy when it was simply pressure that was keeping it a liquid? Where does it get this energy? Would the gas formed be cold... |
Why is it that the potential energy of a system increases when its bonds are broken? (I.e. when a solid turns into a liquid.) I thought the potential energy of the system was mostly contained in these bonds? If these bonds are broken, then why does the system’s potential energy increase? |
When study biology in class, I don't know how my teacher get to the topics on ph value. So, she says that ph stands for percentage hydrogen. Then, I thought there is something strange about it cause acid has a higher percentage of hydrogen then base. But why acid has a low ph value? Is there any mistake on the ph defin... |
I am currently studying about the vespr theory and I'm stuck on an ion which is dichromate (VI) ion $\ce{Cr_2O_7^2-}$. So this is what I am thinking about.
1) If I make the oxygen atom at the middle the centre atom, it is a bent.
2) If I make the chromium atom thecentre atom, it is a tetrahedral.
So, my problem ... |
In 1955, it was proposed that hollow cathode lamps are good emission sources for monochromatic radiation, and thus for atomic absorption spectroscopy ([AAS][1]). In looking into the topic, I've read that "continuum radiation is not preferred in AAS." Why not?
[1]: https://en.wikipedia.org/wiki/Atomic_absorptio... |
Why are hollow cathode lamps used for atomic absorption spectroscopy? |
When study biology in class, I don't know how my teacher get to the topics on pH value. So, she says that pH stands for percentage hydrogen. Then, I thought there is something strange about it cause acid has a higher percentage of hydrogen then base. But why does an acid have a low pH value? Is there any mistake on the... |
Why does an acid have a low pH value? |
I am currently studying about the vespr theory and I'm stuck on an ion which is dichromate (VI) ion $\ce{Cr2O7^2-}$. So this is what I am thinking about:
1) If I make the oxygen atom at the middle the centre atom, it is a bent.<br/>
2) If I make the chromium atom thecentre atom, it is a tetrahedral.
So, my probl... |
Dichromate ion: Tetrahedral or bent? |
There are two points of view for the answer of this question:
- The biological view, the only one that I faced during my research, states that since it can trigger perilous conditions like metabolic acidosis, cause a neurologic sequelae, etc. methanol is toxic.<br/>
- The chemical point of view in an answer, whic... |
The short answer: no, there is no such a general distance.
The long answer: atoms and molecules are not just hanging is the vacuum and waiting someone to grab them. They actually have rather high energy in translation, rotation and vibration modes and particles actually collide during a reaction some of these energi... |
It is well known that when you add salt to ice, the ice not only melts but will actually get colder. From chemistry books I know that salt will lower the freezing point of water. But I’m a little confused as to why it results in a drop in temperature instead of just ending up with water at 0 °C.
What is occurring wh... |
I am having a problem with this equation for redox potentials
> $\Delta G=-nF\Delta E$
In this equation I never am totally sure about what the value of $n$ should be, for example for the reaction shown below, would the $n$ be 2 electrons or 1 electron? Personally, I think it should be 2 electrons because that is ... |
From this [source](http://www.pa.msu.edu/sciencet/ask_st/082593.html)
>Helium is used in scuba tanks to dilute oxygen. Why helium? First, it is chemically inert, that is to say, it does not participate in chemical reactions. Second, helium is much less soluble in water than many other gases, such as nitrogen. The... |
Noob question here. I am a mathematics student doing a course in thermodynamics and am working on the basics now. The question I am asked is: Suppose two states differ in energy by one $\mathrm{eV}$. What can be said about the ratio of the population at $T=300\ \mathrm{K}$. Now it is clear that I will use the formula:
... |
I am having a problem with this equation for redox potentials
$$\Delta G=-nF\Delta E$$
In this equation I never am totally sure about what the value of $n$ should be, for example for the reaction shown below, would the $n$ be 2 electrons or 1 electron? Personally, I think it should be 2 electrons because that is... |
How to determine the value for n in the Gibbs free energy and redox potential equation? |
Air contain 20% O2 by volume. How many cc of air will be required for oxidation of 100cc of acetylene? |
`Why won't water freeze if you put ice in it?`
It will, even at room temperature. You just need a big enough, cold enough ice cube.
Don't believe it? Add a few drops of water to an ice cube in an ice cube tray (which is the same as adding an ice cube to a few drop of water). Wait a few seconds, turn the tray upsi... |
Heyo, I'm sure you all know of the experiment where you take a mixture of ice and water, plop some salt in there and the temperature of the solution progressively drops. The salt increases the entropy of the liquid state, shifting somewhat the ice/water equilibrium towards water. As ice is converted to liquid water, th... |
What is the precise definition of W$_{max}$ in the context of electrochemistry and thermodynamics? |
I'm reading quantum chemistry. The book says that the orbital angular momentum of a $\pi$ electron along the symmetry axis of a molecule made up of two atoms is $\pm 1$. I think this is a primary question, but I do not know why (I'm a student studying physics)
___
I currently have a preliminary understanding of this:... |
Although the wikipedia page on Hydronium indicates a $\mathrm{p}K_\text{a}$ of −1.74, I noticed in the discussion of this page that the subject seems debated (cf. http://en.wikipedia.org/wiki/Talk:Hydronium#pKa.3F) since alternative (apparently more rigorous) reasoning leads to $\mathrm{p}K_\text{a} = 0$ for $\ce{H3O+}... |
My favorite groups of shapes are [cupolas][1]. Are there hydrocarbons in the shape of these similar to how cubane is to a cube? If so how stable are they, and could you please give some general information about each one.
[1]: https://en.wikipedia.org/wiki/Cupola_(geometry) |
I learnt that basic character is directly proportional to the positive inductive effect and inversely proportional ( pls do correct me if i'm wrong). Based on the above mentioned properties how is (CH3)2NH is more basic than CH3NH2 while (CH3)3N is less basic than the secondary amine (CH3)2NH? please do help as soon as... |
I learnt that basic character is directly proportional to the positive inductive effect and inversely proportional (please do correct me if I'm wrong).
> Based on the above mentioned properties how is $\ce{(CH3)2NH}$ is more
> basic than $\ce{CH3NH2}$ while $\ce{(CH3)3N}$ is less basic than the
> secondary amine ... |
Least evil way to make soap? |
I learnt that basic character is directly proportional to the positive inductive effect and inversely proportional to steric hindrance (please do correct me if I'm wrong).
> Based on the above mentioned properties how is $\ce{(CH3)2NH}$ is more
> basic than $\ce{CH3NH2}$ while $\ce{(CH3)3N}$ is less basic than the... |
Pyrite ($FeS_2$) forms cubic crystals, like these ones:
![enter image description here][1]
[1]: https://i.stack.imgur.com/nTLCk.jpg
I know that the crystal structure is primitive cubic, but I don't see how cubic structure on the molecular level translates to cubic structure on much larger scales. If you ar... |
Why does pyrite form cubic crystals? |
What prevents weak acids from dissociating completely in water? |
What prevents weak acids from dissociating completely? |
I learnt that basic character is directly proportional to the positive inductive effect and inversely proportional to steric hindrance (please do correct me if I'm wrong).
> Based on the above mentioned properties how is $\ce{(CH3)2NH}$ is *more
> basic* than $\ce{CH3NH2}$ while $\ce{(CH3)3N}$ is *less basic* than... |
An opened bottle of wine developed into a sour taste and smell of vinegar. Why? |
It seems that your fundamental misunderstanding is that some molecules will dissociate and some will not. Who is to say that they do not dissociate? In fact, virtually every single molecule will dissociate in solution, but the same holds for protonation of the conjugate base. In reality, these molecules are all cons... |
It seems that your fundamental misunderstanding is that some molecules will dissociate and some will not. Who is to say that they do not dissociate? In fact, virtually every single molecule will dissociate in solution, BUT here's the catch: the same holds for protonation of the conjugate base. In reality, these mole... |
I completely don't understand how this method works. My book says : this method works by the principe of **self-absorbtion** which occurs by the emitted radiation of hollow cathode lamp **when it works on high intensity of electricity**, due to which we have more atoms who lead to an extention of emission lines. This i... |
I would like to ask if the hydrogen next to carbonyl group is acidic,and organometallics are strong base, when will it act as a base and extracts the acidic proton and when will it attack the carbonyl carbon?
Also I would also like to ask, for bases when will it attack the acidic proton to form a enolate and when wi... |
When will organometallics act as base or nucleophile? |
I need help understanding the molecule FHF-'s molecular orbital diagram: ![enter image description here][1]
[1]: https://i.stack.imgur.com/bNzio.png
<p>So I know that "a<sub>g</sub>" refers to the 2p<sub>z</sub> and 2s orbitals of fluorine atoms...but I am not sure why "a<sub>g</sub>" is labeled for the topmost orb... |
Understanding FHF- molecular orbital diagram? |
I would like to ask if the hydrogen next to carbonyl group is acidic,and organometallics are strong base, when will it act as a base and extracts the acidic proton and when will it attack the carbonyl carbon?
Also I would also like to ask, for bases when will it attack the acidic proton to form a enolate and when wi... |
I am currently researching as too which is better for purifying a water sample. I have obviously tried the standard Google search for 'Aluminium Sulphate or Ferric Chloride' and have come up with lots of results. The only problem, is that most of these results are based more around peoples opinions or psuedo-scientific... |
Is the peroxide effect observed only with addition of hydrogen bromide and chloroform? If so, why not with other reagents in electrophilic addition on alkenes? |
Why does opened wine develop the sour taste and smell of vinegar? |
>What is the mechanism of the reduction of organic acids with borane?
![enter image description here][1]
[1]: https://i.stack.imgur.com/75NWz.png
[Source](http://www.ch.imperial.ac.uk/rzepa/blog/?p=5114) |
Below is a model example of how to interpret gathered data. Temperature on y-axis, time on x-axis.
We are supposed to read ![enter image description here][2] (temperature change by neutralization) and ![enter image description here][1] (temperature change by resistive heating - to determine heat capacity of calorimete... |
$$\ce{C_{(s)} + H_2O_{(g)} <=> CO_{(g)} + H_{2(g)}}$$
$$\Delta H = +131\ \mathrm{kJ}$$
If the reaction is in a state of equilibrium under standard conditions, what can be done to increase the value of $K_\text{eq}$?
My question is would you have to increase or decrease the temperature to increase $K_\text{e... |
I bought an electronic meter which measures the concentration of oxygen in air. But I think the sensor has failed because it is too old, as it had a crusty substance coming from it.but I can no longer find spare sensors for it.
How might this sensor have worked? I assume that its resistance changed as air was passed... |
I bought an electronic meter which measures the concentration of oxygen in air. But I think the sensor has failed because it is too old, as it had a crusty substance coming from it.but I can no longer find spare sensors for it.
How might this sensor have worked? I presume the property of some substance was measured;... |
I bought an electronic meter which measures the concentration of oxygen in air. But I think the sensor has failed because it is too old, as it had a crusty substance coming from it.but I can no longer find spare sensors for it.
How might this sensor have worked? I presume the property of some substance was measured;... |
I bought an electronic meter which measures the concentration of oxygen in air. But I think the sensor has failed because it is too old, as it had a crusty substance coming from it.but I can no longer find spare sensors for it.
How might this sensor have worked? I presume the property of some substance was measured;... |
I bought an electronic meter which measures the concentration of oxygen in air. But I think the sensor has failed because it is too old, as it had a crusty substance coming from it.but I can no longer find spare sensors for it.
How might this sensor have worked? I presume the property of some substance was measured;... |
I cannot say as to your specific sensor, but most oxygen sensors are electrochemical sensors built around concentration cells.
Take a look at the following diagram of a [simple zirconia-based oxygen probe][1] from Wikipedia. This type of sensor is very like the one in automobiles.
![diagram of zirconia-based sens... |
>What is the mechanism of the reduction of organic acids with borane?
![enter image description here][1]
Source:
Henry Rzepa. Chemistry with a twist. Mechanism of the reduction of a carboxylic acid by borane: revisited and revised. October 16th, 2011. http://www.ch.imperial.ac.uk/rzepa/blog/?p=5114
DOI: [... |
Pyrite ($\ce{FeS2}$) forms cubic crystals, like these ones:
![enter image description here][1]
[1]: https://i.stack.imgur.com/nTLCk.jpg
I know that the crystal structure is primitive cubic, but I don’t see how cubic structure on the molecular level translates to cubic structure on much larger scales. If yo... |
This might sound funny but my friend asked me why most - if not every - faeces are of a brown or brownish color?
Why not grey or slightly bluish or green for example?
Is there any simple scientific explanation for this?
Thanks |
Why most excreta are brown? |
I always wonder that though Both ***NaCl*** and ***CsCl*** are alkali halides, why they adopt different crystal forms, FCC and BCC respectively? and I have a doubt about ***CsCl*** structure that Why the *Cs+* or *Cl-* ions are not located at voids/lattice points as like as ***NaCl*** structure? |
Why so differance in alkali halide's crystal forms? |
I always wonder that though Both $\ce{NaCl}$ and $\ce{CsCl}$ are alkali halides, why they adopt different crystal forms, FCC and BCC respectively? and I have a doubt about $\ce{CsCl}$ structure that Why the $\ce{Cs+}$ or $\ce{Cl-}$ ions are not located at voids/lattice points as like as $\ce{NaCl}$ structure? |
I was linked to a Kickstarter for a cooling ball to be placed in drinks which claims with constant marketing hyperbole how much it relies on "Phase Change" ! which is a neat concept and seems not unreasonable, but in thinking about it I'm failing to imagine (as I'm no chemist, and of ill education) what refrigerant cou... |
I'm a freshman recently learned how to do TLC and column chromatography. I also know a little about other ways to separate things by chromatography, such as affinity chromatography, gel chromatography, ion exchange chromatography, and gas chromatography, but without many details.
Here I meet a problem to solve a quest... |
How to choose a proper chromatography way to separate substrates? |
In tandem mass spectrometry of proteins one will usually end up with a mix of $b$ and $y$ fragments but also $a$ fragments and immonium fragments. My problem is that wouldn't an $\ce{a1}$ ion be the exact same as an immonium ion of the first amino acid in the peptide? |
I'm a freshman recently learned how to do TLC and column chromatography. I also know a little about other ways to separate things by chromatography, such as affinity chromatography, gel chromatography, ion exchange chromatography, and gas chromatography, but without many details.
Here I meet problems to solve a questi... |
> Is the peroxide effect observed only with addition of hydrogen bromide
> and chloroform?
No, it is observed with other compounds too, $\ce{CCl4}$ and the halogens are examples.
Also, just to be clear, these reactions involve the addition of radicals ($\ce{X^{.}}$), not electrophiles, to alkenes (or alkynes).
... |
> Is the peroxide effect observed only with addition of hydrogen bromide
> and chloroform?
No, the "peroxide effect" or "Markovnikov" addition of a free radical to an unsaturated bond is observed with other compounds too, $\ce{CCl4}$ is another example.
Also, just to be clear, these reactions involve the additi... |
I have some problems with water and metals in binding site when using Autodock Vina.
Is it possible to make these flexible? They unfortunately remain where they are what leads to wrong interactions.
My other idea would be to delete it before docking, reinsert them and minimize everything.
Does anyone have a so... |
If I use flexible residues in the binding pocket, they are cut from the file.
The protein is broken and the amino acids are unbound in the room.
How can I get my results and the protein together again?
![enter image description here][1]
[1]: https://i.stack.imgur.com/hvVlz.png |
It is known, that decomposition of Lead(II) nitrate is one of the ways of generating $\ce{NO2}$ for lab use.
I recently did this in order to acquire $\ce{NO2}$ in liquid form (ambient temperature was ~0 °C), and got quite strange results. First, liquid $\ce{NO2}$ had 2 visible layers, usual brown one at the top and... |
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