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Why will A atoms diffuse from $\beta$ phase to $\alpha$ phase and B atoms from $\alpha$ phase to $\beta$ phase? |
> [![Molar free energy plot][1]][1]
> At the initial compositions 1 and 2 of $α$ and $β$ respectively the chemical potentials of A and 13 atoms in each phase can be found by extrapolation of the tangents to the free energy curves at 1 and 2 to the corresponding sides of the free energy diagram, as shown above.
> ... |
Why will A atoms diffuse from β phase to α phase and B atoms from α phase to β phase? |
[Watts up][1] referred to the [South China Morning Post][2] in reporting that a Tsinghua University team led by Wei Fei claimed in 2018 to have manufactured carbon nanotube fibre has tensile strength of 80 gigapascals.
Has this result been verified or reproduced independently?
The study was published in Nature an... |
Has there been any independent verification of the results from this Chinese nanotube study? |
[Watts up][1] referred to the [South China Morning Post][2] in reporting that a Tsinghua University team led by Wei Fei claimed in 2018 to have manufactured carbon nanotube fibre has tensile strength of 80 gigapascals.
Has this result been verified or reproduced independently?
The study was published in Nature an... |
In the last step of Kjeldahl method, the unreacted HCl in the solution is back titrated with a standard NaOH and the concentration of HCl that has been used to neutralize the ammonia is then calculated. However, other than HCl, there also exist an acid in the solution that can be titrated with NaOH which is the protona... |
#The problem#
[![enter image description here][1]][1]
Source : MS Couhan (problems in organic chemistry . Chapter: Alcohols , phenols and ethers).
#My Thoughts#
[![enter image description here][2]][2]
If I proceed along $\ce{path 1}$ , $\ce1a$ is formed . It is unstable due to inductive withdrawing effect of... |
What is the major product obtained on acidification of substituted epoxide? |
I was told each compound has an enthalpy of formation of 0 at the standard temperature if it is in it's lowest energy modification. But what if we change the temperature? It would make sense to me that we would also need to have a non-zero enthalpy of formation then, like for Hydrogen at 400K. Is that the case? Many ex... |
I have a plasma consisting of elements A and B (which have a similar mass). These elements can react to form molecules AB.
$$
\ce{A + B -> AB}
$$
Now if my plasma or gas is expanding based on pressure gradients, I will have some sort of diffusion of these two element concentrations. Based on my spectroscopic an... |
What is the order of bond dipole moments for S-O, Si-O, P-O and Cl-O in the compounds $\ce{SO3, SiO2, P2O5,}$ and $\ce{Cl2O7}$? This question is from a book and the answer given is $\ce{Cl-O < S-O < P-O < Si-O}$. Can someone explain why? When I drew the Lewis structures and applied VSEPR theory, it seemed that all the ... |
> The standard hydrogen electrode potential by conventional at 298 K is taken to be 0.00 volts.
This is what I have been taught. It talks about SHE at 298 K, so is the hydrogen electrode potential at a temperature other than 298 kelvin also defined to be zero ? If not, how do we calculate at any other temperature? |
Is the Standard hydrogen electrode potential at T other than 298 K also zero? |
In the last step of Kjeldahl method, the unreacted $\ce{HCl}$ in the solution is back titrated with a standard $\ce{NaOH}$ and the concentration of $\ce{HCl}$ that has been used to neutralize the ammonia is then calculated. However, other than $\ce{HCl}$, there also exist an acid in the solution that can be titrated wi... |
What is the order of dipole moments for $\ce{SO3, SiO2, P2O5,}$ and $\ce{Cl2O7}$? This question is from a book and the answer given is $\ce{Cl2O7 < SO3 < P2O5 < SiO2}$. Can someone explain why? When I drew the Lewis structures and applied VSEPR theory, it seemed that all the given compounds have zero dipole moment. |
Here's a "simple" bond diagram of 1,1,1,2-Tetrafluoroethane which I believe is a Lewis structure:<br/>
![1,1,1,2-Tetrafluoroethane][2]<br/>
Ok, that's easy enough - four bonds from each Carbon atom, and each Fluorine atom having one bond.
Here are some more "complicated" bonds which I have yet to do in my high sch... |
Here's a "simple" bond diagram of 1,1,1,2-Tetrafluoroethane which I believe is a Lewis structure:
![1,1,1,2-Tetrafluoroethane][2]
Ok, that's easy enough - four bonds from each carbon atom, and each fluorine atom having one bond.
Here are some more "complicated" bonds which I have yet to do in my high school ch... |
How do you name this compound using IUPAC system (including steps)? |
Here's a "simple" bond diagram of 1,1,1,2-Tetrafluoroethane which I believe is a Lewis structure:
[![1,1,1,2-Tetrafluoroethane][2]][2]
OK, that's easy enough - four bonds from each carbon atom, and each fluorine atom having one bond.
Here are some more "complicated" bonds which I have yet to do in my high scho... |
And including stereochemistry (cis trans or R S )
I was told I should demonstrate some effort to explain my knowledge of underlying concepts (which are concepts that I already know?)
So here it is : I know you start numbering from the double bond because t... |
I want to create my own charcoal disks/tablets which will be mainly used for incense and I want each of the charcoal disks to glow different colours (eg one disc glows blue, another glows red etc.). The product will be using charcoal and other ingredients including Arabic gum. I will need to add certain chemicals such ... |
And including stereochemistry (cis trans or R S )
I was told I should demonstrate some effort to explain my knowledge of underlying concepts (which are concepts that I already know?)
So here it is : I know you start numbering from the double bond because t... |
And including stereochemistry (cis trans or R S )
I was told I should demonstrate some effort to explain my knowledge of underlying concepts (which are concepts that I already know?)
So here it is : I know you start numbering from the double bond because t... |
The best way for you to find out if a chemical is safe for your use case would be to look at the safety data sheets for your chemicals. For your convience, I have linked to relevant ones below.
- [Copper (II) Chloride][1]
- [Calcium Chloride][2]
- [Borax][3]
- [Copper (II) Sulfate][4]
- [Alum][5]
- [Stro... |
The best way for you to find out if a chemical is safe for your use case would be to look at the safety data sheets for your chemicals. For your convience, I have linked to relevant ones below.
- [Copper (II) Chloride][1]
- [Calcium Chloride][2]
- [Borax][3]
- [Copper (II) Sulfate][4]
- [Alum][5]
- [Stro... |
How to calculate the number of atoms in a gas molecule? |
The equilibrium constant (EC) of a certain reaction is only dependent on temperature. For instance, suppose at a certain temperature, the EC of $\ce{A + 3B <=> 2C}$ is $K$. Now if I divide the whole equation by 2 to get $\ce{(1/2)A + (3/2)B <=> C}$, why will my new EC $K'$ be the square root of the previous one,namely ... |
I am trying to understand the structure of elemental, crystalline sulfur. I read that it is face-centered orthorhombic. My question is whether each point on the unit lattice contains a single atom of sulfur or a S6 molecule?
Thanks to anyone reading. |
Can sulphur react with calcium carbonate to form sulphur trioxide and calcium carbide, as the energy of 3(S=O) is greater than ((C=O) +2(C-O))? |
> [OP:] It is usually said that fuel contains energy and that oxygen only enables the release of energy in the sense like enzymes enable reactions.
An enzyme is a catalyst, so it does not change the enthalpy of a reaction. That part is correct. "Oxygen only enables the release of energy" is incorrect. Oxygen is one ... |
I melted about 2 kg of gallium and put it in a plastic container, in order to make crystals. After letting them grow and extracting them, I let the gallium freeze at the room temperature, which is below the melting point.
However, for some reason there is a small quantity of gallium (10-20 g) that is not freezing af... |
Pure gallium with lower melting point? |
> [![Molar free energy plot][1]][1]
> At the initial compositions 1 and 2 of $α$ and $β$ respectively the chemical potentials of A and B atoms in each phase can be found by extrapolation of the tangents to the free energy curves at 1 and 2 to the corresponding sides of the free energy diagram, as shown above.
> A... |
What is the heat of formation when weak acid reacts with weak base? |
**Reason for rewrite**: refer to edit summary.
----------
From [Wikipedia](https://en.m.wikipedia.org/wiki/Disulfur) on Disulfur ($\ce{S2}$)
> This violet gas is commonly generated by heating sulfur above 720 °C
Since the sulfur is well above $720^\circ\pu{C}$, it would most likely be in the diatomic sta... |
**Strong acid and strong base**
First, lets see where the enthalpy of $\pu{-57.3 kJ/mol}$ comes from. In aqueous solution, strong acids and bases react completely to form $\ce{H+}$ and $\ce{OH-}$, respectively. The neutralization of a strong acid with a strong base then is always the same reaction:
$$\ce{H+(aq) +... |
**Strong acid and strong base**
First, lets see where the enthalpy of $\pu{-57.3 kJ/mol}$ comes from. In aqueous solution, strong acids and bases react completely to form $\ce{H+}$ and $\ce{OH-}$, respectively. The neutralization of a strong acid with a strong base then is always the same reaction:
$$\ce{H+(aq) +... |
[![enter image description here][1]][1]
How is the concept of diagram(b) different from that of (e) and (d) from (f)?Someone told me in one of my earlier posts that he is used to see graphs with two minimia but somewhere where we had two phase separately named as $G^{\alpha}$ and $G^{\beta}$ vs the composition curve... |
What is the heat of reaction of weak acid reacting with weak base compared to strong acid reacting with strong base? |
[![enter image description here][1]][1]
How is the concept of diagram(b) different from that of (e) and (d) from (f)?Someone told me in one of my earlier posts that he is used to see graphs with two minimia but somewhere where we had two phase separately named as $G^{\alpha}$ and $G^{\beta}$ vs the composition curve... |
**Strong acid and strong base**
First, lets see where the enthalpy of $\pu{-57.3 kJ/mol}$ comes from. In aqueous solution, strong acids and bases react completely to form $\ce{H+}$ and $\ce{OH-}$, respectively. The neutralization of a strong acid with a strong base then is always the same reaction:
$$\ce{H+(aq) +... |
And including stereochemistry (cis trans or R S )
I know you start numbering from the double bond because there are no functional groups like -OH, you take the longest carbon chain which is six carbons in this question, so now it should be 3-bromo-3-methyl-... |
**Strong acid and strong base**
First, lets see where the enthalpy of $\pu{-57.3 kJ/mol}$ comes from. In aqueous solution, strong acids and bases react completely to form $\ce{H+}$ and $\ce{OH-}$, respectively. The neutralization of a strong acid with a strong base then is always the same reaction:
$$\ce{H+(aq) +... |
I would like to identify if a wine glass is made of lead crystal (a destructive method is allowed). Lead crystal is said to be eroded by dishwasher detergent. I don't have a dishwasher, what causes the stains? Could I quickly identify lead crystal by exposing it to hot caustic soda? |
How to identify lead crystal glassware? |
I need to dope Gallium with a small amount of a Fluorine compound. My thought was to add a metal Flouride to liquid Gallium at an appropriate temp/pressure to have it dissolve in the liquid metal.
I am considering a few options; SnF2, GaF3, and NaF
Gallium Fluoride would be the best for my application, but the ot... |
I am a biologist currently doing field work where I need to quickly dry leaf samples using silica gel crystals. I use the orange indicating kind that are 2-4mm in size. The setup is like this. I stuff 1-2 leaves in a manila paper envelop which I drop in a ziplock bag containing ~1/8th cup of silica gel. Then I squeeze ... |
Is presence of air necessary for silica gel to absorb moisture? |
I want to create my own charcoal disks/tablets which will be mainly used for incense and I want each of the charcoal disks to glow different colours (eg one disc glows blue, another glows red etc.). The product will be using charcoal and other ingredients including Arabic gum. I will need to add certain chemicals such ... |
> The Hinsberg test of $\ce{C5H14N2}$ compound produces a solid that is insoluble in 10% aq. $\ce{NaOH}.$ This solid derivative disssolves in 10% aq. $\ce{H2SO4}.$ Which of the following would best fit these facts?
> [![enter image description here][1]][1]
I think **b** is the answer.
[1]: https://i.stack.... |
What happens when Hinsberg derivative is added to acidic solution? |
_Note: If this question does not belong on this Stack Exchange, please direct me to a more appropriate Stack Exchange._
----------
**This is a "creative chemistry" question as much or more-so than a "give me the facts" type of question. Should be of interest to anyone who finds the topic of plausible alternative ... |
[![enter image description here][1]][1]
How is the concept of diagram(b) different from that of (e) and (d) from (f)?Someone told me in one of my earlier posts (https://chemistry.stackexchange.com/questions/118244/why-will-a-atoms-diffuse-from-%ce%b2-phase-to-%ce%b1-phase-and-b-atoms-from-%ce%b1-phase-to-%ce%b2-p) t... |
First, I'll go ahead and say I'm not very versed in chemistry. My question comes from my interest in planetary-sciences, specifically the speculation that there are likely exoplanets and moons with surface oceans of water-ammonia. However I can't find much hard info on how a vast body (i.e. ocean) of water-ammonia woul... |
The dipole moment of ethyl chloride is 2.10 D ([*J. Mol. Struct.* **1990,** *216*, 9–26](https://doi.org/10.1016/0022-2860(90)80313-9)), and that of vinyl chloride is 1.42 D ([*J. Chem. Phys.* **1960,** *32* (1), 205–209](https://doi.org/10.1063/1.1700901)).
Why is this the case? I would have thought that hyperconju... |
**Freezing**
>I've heard that the freezing and boiling points of the mixed liquid would exist on some continuum between the freezing and boiling points of its constituent liquids (ammonia and water), varying depending on the exact mix ratio and of course pressure. Is that correct?
For freezing points, that is inc... |
I am involved in a project that is testing approaches to using CVD to form a graphene layer on liquid Gallium. Fluorine has been used in the process to disassociate methane into carbon and hydrogen and to speed the deposition of carbon. In our project, we are using Acetelyne.
We want to try a different approach of ... |
Here is what I know:
Sapphires are composed primarily of $Al_2$$O_3$ (in pure form colorless) as well as Fe and Ti (trace impurities responsible for the color). I know that the proportion of these trace elements gives rise to various colors but I just want to focus on the combination that gives blue right now.
... |
Why do sapphires appear blue to our eyes? |
Burning hydrogen releases a little more energy than burning carbon, correct?
And methane is CH4, but coal is mostly C, correct?
So shouldn't burning pure carbon release five times the CO2 (Assuming combusting carbon releases the same energy as hydrogen), or even six times per unit energy 'released'/'created' by t... |
Why doesn't natural gas combustion release only one-sixth as much carbon dioxide as coal burning? |
If humans disappeared today, and aliens visited in the future, for how long would plastic be detectable on the planet, using known or plausible technology. I'm mostly interested in accidental preservation of plastic (buried in sediment, microplastics in the ocean, etc.), but also the long-term stability if, for instanc... |
I am involved in a project that is testing approaches to using CVD to form a graphene layer on liquid Gallium. Fluorine has been used in the process to disassociate methane into carbon and hydrogen and to speed the deposition of carbon. In our project, we are using Acetelyne.
We want to try a different approach of ... |
This is a famous reaction to generate singlet oxygen. I am not how do you generate HOCl. If these two components (hypochlorite ion, and peroxide ion) are reacted under certain alkaline conditions, oxygen is immediately evolved with a red glow. One is left with chloride ions and water. Video link here
https://www.you... |
What is the pH of xylene, and is it considered to be a corrosive substance?
Specifically I am interested in how xylene might interact with electrical conductors and components, which contain copper, aluminum, and steel as well as plastic.
I can't seem to find a pH reading online (checked Wolfram Alpha, Wikipedia,... |
Is xylene an acid? |
What is the activation energy barrier of uncatalyzed nitrogen fixation? |
I would like to make Na2CO3 react with HCl in a closed fixed volume vessel, and accordingly I'd like to understand how ensuing pressure will affect the equilibrium of my reaction (and to which extent my reaction will affect the level of pressure when equilibrium is reached).
I guess that the link between pressure ... |
Why there is only little difference b/w Molecular Dipole moments in CHX3 compounds(X=Cl,Br,I)?
-------
As we can see there is a huge difference in dipole moment of Methyl halides F,Cl,Br,I excluding CHX3
[![enter image description here][1]][1]
[1]: https://i.stack.imgur.com/r0ASw.jpg
Please explain the r... |
Why there is only little difference b/w Molecular Dipole moments in CHX3 compounds(X=Cl,Br,I)? |
Why is there only little difference between molecular dipole moments in $\ce{CHX3}$ compounds ($\ce{X}$ = $\ce{Cl}$, $\ce{Br}$, $\ce{I}$)?
-------
As we can see there is a huge difference in dipole moment of methyl halides $\ce{F}$, $\ce{Cl}$, $\ce{Br}$, $\ce{I}$ excluding $\ce{CHX3}$.
[![enter image descripti... |
Why is there only little difference between molecular dipole moments in CHX3 compounds (X = Cl, Br, I)? |
My textbook says the following in a section on **Miller indices**:
> Adjacent planes $(hkl)$ in a simple cubic crystal are spaced a distance $d_{hkl}$ from each other, with $d_{hkl}$ given by:
> $$d_{hkl} = \dfrac{a}{\sqrt{h^2 + k^2 + l^2}} \tag{2.12}$$
> where $a$ is the lattice constant. Equation $2.12$ prov... |
When mixing HCl with K2CO3, the reaction that is usually given is the following:
K2CO3 + 2HCl → 2KCl + CO2 + H2O
I am wondering, however, if I could produce KHCO3 from K2CO3, by using half as many moles HCl. The reaction I imagine could happen would be expressed as follows:
K2CO3 + HCl → KHCO3 + KCl
I've... |
Is this reaction possible? |
What is the simplest way (or least complicated way) to generate parameter files (.skf) to be used with DFTB+, for example?
Assuming I want to be able to reproduce geometries for a certain type of molecules, how would I go about it? |
How to generate Density Functional Tight Binding parameters (Slater-Koster files)? |
By writing $\ce{AB.xCD}$ chemists mean that there are CDs are found in the crystalline framework of AB. The most common example of this is water trapped inside the crystal structure of ionic compounds. (See [water of crystallization in wikipedia][2])
An example that's often taught is $\ce{CuSO4.5H2O}$. See that 5 th... |
Can sulphur react with calcium carbonate to form sulphur trioxide and calcium carbide, as the energy of 3(S=O) is greater than ((C=O) +2(C-O))?
EDIT: i forgot to say that this is in an oxygen-free environment. |
>1 mol of acetic acid and 1 mol of ethanol was mixed to react at a constant pressure to reach the equilibrium, and 0.75 mol of water was found in the product.
>A. Calculate the equilibrium constant of this reaction at the above temperature
>B. At the same temperature, 1 mol acetic acid, 1 mol ethanol, and 4 mol ... |
How much ethylacetate is produced? |
> The Hinsberg test of $\ce{C5H14N2}$ compound produces a solid that is insoluble in 10% aq. $\ce{NaOH}.$ This solid derivative disssolves in 10% aq. $\ce{H2SO4}.$ Which of the following would best fit these facts?
> [![enter image description here][1]][1]
I think **b** or **d** is the answer.
The reason being -... |
I am editing a chemistry-related paper and the synthesis procedure described is as follows:
> Then, 10 mL of the intermediate were mixed with 10 mL of 1% (w/v)
> VCPL and 2 mL of 0.1% (w/v) KPS.
I was wondering if one should add the word "solution" after the name of the ingredients as follows:
> Then, 10 mL ... |
Is adding the word "solution" necessary when listing the materials used in a synthesis? |
Here is what I know:
Sapphires are composed primarily of $Al_2$$O_3$ (in pure form colorless) as well as Fe and Ti (trace impurities responsible for the color). I know that the proportion and identity of trace elements gives rise to various colors but I just want to focus on the combination that gives blue right no... |
What gives rise to the color of sapphires? |
_Note: If this question does not belong on this Stack Exchange, please direct me to a more appropriate Stack Exchange._
----------
**This is a "creative chemistry" question as much or more-so than a "give me the facts" type of question. Should be of interest to anyone who finds the topic of plausible alternative ... |
In Szabo and Ostlund's Modern Quantum Chemistry, the matrix elements for the hamiltonian of a two-electron system, with an operator $\hat O$, are written on pages 64-66 as
$$\langle \Psi_0 | \hat O | \Psi_0 \rangle=\int dx_1 dx_2 [2^{-\frac{1}{2}} (\chi_1(x_1)\chi_2(x_2)-\chi_2(x_1)\chi_1(x_2))]^* \cdot \hat O [2^{-... |
My textbook says the following in a section on **Miller indices**:
> Adjacent planes $(hkl)$ in a simple cubic crystal are spaced a distance $d_{hkl}$ from each other, with $d_{hkl}$ given by:
> $$d_{hkl} = \frac{a}{\sqrt{h^2 + k^2 + l^2}} \tag{2.12}$$
> where $a$ is the lattice constant. Equation $2.12$ provi... |
No, the repeated addtion of the word "solution" is not needed.
All you want here is to provide a *measured* quantity (e.g., volume), concentration of your reagent in the solvent, and *inferred* quantity (e.g., mmol). This may be reported in the following pattern, too:
> "1-Cinnamyl-4-methylbenzene (**4a**): The ... |
In Szabo and Ostlund's Modern Quantum Chemistry, the matrix elements for the hamiltonian of a two-electron system, with an operator $\hat O$, are written on pages 64-66 as
$$\langle \Psi_0 | \hat O | \Psi_0 \rangle=\int dx_1 dx_2 [2^{-\frac{1}{2}} (\chi_1(x_1)\chi_2(x_2)-\chi_2(x_1)\chi_1(x_2))]^* \cdot \hat O [2^{-... |
Here is what I know:
Sapphires are composed primarily of $\ce{Al2O3}$ (in pure form colorless) as well as Fe and Ti (trace impurities responsible for the color). I know that the proportion and identity of trace elements gives rise to various colors but I just want to focus on the combination that gives blue right n... |
> The Hinsberg test of $\ce{C5H14N2}$ compound produces a solid that is insoluble in 10% aq. $\ce{NaOH}.$ This solid derivative dissolves in 10% aq. $\ce{H2SO4}.$ Which of the following would best fit these facts?
> [![enter image description here][1]][1]
I think **b** or **d** is the answer.
The reason being it... |
I am currently learning about electrochemistry using Zumdahl 10th ed. One of the critical thinking questions is "Why can't Zn be plated out from an aqueous solution of Zn2+ using the options in table 18.1?"
[![Table of Half Reactions][1]][1]
[1]: https://i.stack.imgur.com/xmAXE.jpg
I feel like it would be ... |
Why can't zinc be plated out from a solution of zn2+ ions using options from the table (image in post)? |
If i found a calcium salt that is soluble in acetone or ethyl acetate, which are polar aprotic solvents, and attempted electrolysis, what would happen? Since polar aprotic solvents are used in metal-air batteries I don't think there would be a reaction between the newly formed metal and solvent. At the same time, no on... |
How does De broglie actually proves Bohr's postulates? |
I stumbled the next question: the burning enthalpy (exothermic) of $\ce{NO +O2 ->NO2}$ is $\ce{57Kj}$ and $\ce{O=O}$ bond energy is $\ce{494Kj}$, then what is the bond energy of $\ce{N-O}$ ?
So I balanced the equation $\ce{2NO + O2 ->2NO2}$ wrote down lewis structures and got: $\ce{(2*[N=O] + [O=O]) - 2([N-O] + [N=O... |
I am currently learning about electrochemistry using Zumdahl's *Chemistry* \[1, pp. 709–710\]. One of the critical thinking questions is
> Why can $\ce{Zn}$ not be plated out from an aqueous solution of $\ce{Zn^2+}$ using the choices in Table 18.1?
> [![TABLE 18.1 | Standard Reduction Potentials at 25 °C (298 K) ... |
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