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1answer
28 views

Partial dissolution of non-polar solutes in polar solvents

I have learnt that in order for dissolution to occur, the solute-solvent intermolecular forces must be strong enough to overcome the solute-solute and solvent-solvent forces. However if this is the ...
0
votes
1answer
60 views

H and H- atomic and ionic radius

A hydrogen anion has a bigger radius than neutral H . Why is this happening ? I mean both electrons exist at the same shell so this is not it. Both H- and H have 1 proton so this is not it as well . ...
15
votes
1answer
523 views

Why does this image of cyclocarbon look like a nonagon?

The $C_{18}$ allotrope cyclocarbon has been synthesized and imaged. Science has most details behind a paywall, but this discussion includes an image: In this octakaidecagonal molecule, each $\color{...
-2
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0answers
17 views

Product of electrophilic substitution reaction [on hold]

In the following Electrophilic (probably substitution) reaction of the compound with chlorine in the presence of Aluminium chloride what should be the product and why? I am not sure about its name ( ...
0
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1answer
44 views

Synthesis of copper selenide

If I react selenium powder with copper chloride powder above the melting point of selenium (221 °C), will I end up with a chunk of copper selenide, with the chlorine given off as gas, or will I lose ...
-1
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0answers
20 views

Is the black carbon powder useful for preparing printers black ink(water-inks)?

I need to prepare black water ink for printers. Is The carbon black powder is the right pigment to create black water ink for printers. What are the specifications of the perfect black carbon powder ...
-2
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0answers
18 views

Why at lower pH than pKa, acid doesn't dissociate to give H+ ions [on hold]

I understand mathematically that pH lower than that of pKa, acid will be present in undissociated form but can anyone explain it qualitatively (logic) why it is so?
0
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0answers
22 views

Do any decent thermochemical databases exist? [duplicate]

The more thermochemical properties the better, but specific heat/ specific heat capacity is what I am looking for.
0
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0answers
14 views

Why does the dipole moment order of group 15 hydrides increase down the group?

The order given in my book is NH3>SbH3>AsH3>PH3 Phosphorous is more electronegative than As and Sb then shouldn't the dipole moment be more in case of PH3 . And why does the anomaly of NH3 occur?
-2
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0answers
16 views

How to calculate the ionic product of Pb2SO4? [on hold]

At 18°C the solubility product of Lead(II)Sulphate is given $ 1.8×10^{-8}$. If we mix 40ml $1.5×10^{-4}$ M $\ce{Na2SO4}$ solution into 10ml .001 ml $\ce {Pb(CH3COO)2} $ solution, will Ionic product be ...
0
votes
1answer
58 views

Symmetry Space Group Diagram

I am doing an introductory course to Crystallography and I have found in the following web page: http://pd.chem.ucl.ac.uk/pdnn/symm3/sgmonoc.htm a guide for the elaboration of the diagrams of the ...
1
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0answers
23 views

Determining the composition of basic copper sulfate by titrimetry

A colleague shared an undergraduate level classical gravimetry/titrimetry experiment on determining the stoichiometry of basic copper sulfate. I am looking for a reference for this type of experiment. ...
-2
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0answers
31 views

Possible Applications of this 18 Carbon Ring [on hold]

I recently read this article which claims that scientists have managed to isolate 18 Membered Carbon Rings and I want to use it for a project however I also need to enlist it's possible applications ...
0
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0answers
23 views

Why does ammonia have higher melting point but lower boiling point than HF? [duplicate]

I guess the reason is hydrogen bonding, but shouldn't both the trends be similar in that case?
1
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0answers
39 views

Electronic configuration of Co³⁺

Cobalt (atomic number 27) has electronic configuration $[\ce{Ar}]\mathrm{(4s)^2 (3d)^7}.$ I have seen two different configurations and explanations for $\ce{Co^3+}$ from a variety of different ...
0
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0answers
13 views

Question based on finding impurity of a sample of Sodium bicarbonate

12.5g of commercial sodium bicarbonate gives 3 g of carbon dioxide. What is the percentage in purity in the sample? $$\ce{2NaHCO_3 -> Na_2CO_3 + CO_2 + H_2O}$$ I have solved this question, but I ...
-2
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0answers
20 views

How to calculate pH of final solution using volume and pH of initial solutions? [on hold]

When two solutions of equal volume with pH 2 and 8 are mixed, what happens to resulting pH ? How to calculate the final pH? I am being too specific this time.
0
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0answers
12 views

Effect of the reaction stoichiometric coefficients on Δn [on hold]

We have ΔH=ΔE+RTΔn for any chemical reaction (suppose ideal gases) where Δn is the difference between the stoichiometric coefficients of the gaseous products and gaseous reactants. Note that ΔH in J/...
5
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0answers
36 views

Cauchy-Schwarz integral screening different inequalites

Eq. (9.12.23) in [1] states that: $$\sum_{abcd}c_{ab}c_{cd}g_{abcd}>0\tag{MEST 9.12.23}\label{91223}$$ with $c_{ab}=c_ac_b$ for $c_a$ being some distribution coefficients and $g_{abcd}$ being the ...
0
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0answers
14 views

PV Cell materials for efficiency

I was watching a show on PV cells and said they can only get to 40% efficiency because of the materials that they are using. I was wondering if you can dope a different semiconductor substance like ...
-1
votes
1answer
27 views

Exact weights for a chemical reaction og Silver and Nitric Acid [on hold]

I'm an amateur analog photographer and want to react Nitric Acid (62%) and silver to Silver nitrate. Silver nitrate is the basis for almost all black and white photography. I'm trying to figure out ...
2
votes
1answer
24 views

Why is activation energy drawn in a potential energy diagram in reactions?

I learned in chemistry class that activation energy is the av. KE that the colliding particles need in order to successfully react. However, they are always drawn as a "hill" in a PE diagram. I do ...
0
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1answer
26 views

Numerical simulation and calculations of pH

a. Reaction of $\ce{CO2}$ addition in water is as follows: $\ce{CO2}$ + $\ce{H2O}$ $\ce{->}$ $\ce{H2CO3}$ b. Then, pH of $\ce{H2CO3}$ solution is increased to 12 by addition of 1M $\ce{NaOH}$. ...
3
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0answers
13 views

Ethyl acetate produces red colour on ceric ammonium nitrate test

When I did CAN test on ethyl acetate red colour was seen. I thought water may get added with Ethyl acetate to produce this compound which in turn gave red coloration but carbon should not make three ...
1
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0answers
11 views

How to improve the cation exchange capacity (CEC) of sand? [on hold]

How can the cation exchange capacity (CEC) of sand be best improved and what are the ways to measure it?
0
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1answer
26 views

Which of these reactants will not generate this racemic amine?

I understand that in E there is no electrophile the amine can attack, however, I do not understand why A is an answer as well. The amine in A can perform an intramolecular attack on the aldehyde and ...
-1
votes
1answer
35 views

Is it possible to predict release of acid fumes in certain acid reactions? [on hold]

Upon mixing both acids, the reaction between Formic Acid and Sulfuric Acid, besides producing Carbon Monoxide and Water, releases a certain amount of acid fumes. Does anyone know if the fumes, in ...
-1
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0answers
19 views

Calculating triple point using freezing and boiling point depression

On this website, I read that when an solute(lets say NaCl) is added to a solvent(lets say water),the boiling point and melting point shift by a certain amount. If, in our experiment, we keep the ...
0
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0answers
16 views

A Numerical on Vacancy concentration [on hold]

$Question:$ Calculate the equilibrium value of vacancies concentration for copper per atom of the order of $10^4$ at $1000K$ the energy for vacancy formation is $0.9eV/atom\\$. $\\Answer:N=N_0+exp(-Q/...
0
votes
1answer
46 views

Why the formation of PH4+ is difficult compared to NH4+?

My textbook asks this as an objective question. What I had in mind was that the lone pair on phosporous was more distributed as compared to nitrogen(since nitrogen is more electronegative and smaller ...
-2
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0answers
13 views

Spectroscopy and Chromatography [on hold]

25 cm^3 of an unknown solution has an absorbance of 0.3. Added is 5 cm^3 of a solution of the same compound (concentration = 10 ppm) and absorbance is now 0.34. Calculate the original unknown ...
-3
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0answers
25 views

Ease of formation of 3 membered heteroatomic rings [on hold]

A three membered ring is easier to form than a four membered one, although the former has a larger ring strain.. Why???
1
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0answers
15 views

How to extract melanin from human hair [on hold]

I am working on a project wherein I am studying various properties of human hair and its utilization..I would like to know method by which we can extract melanin from human hair. Can anyone suggest ...
1
vote
0answers
18 views

Is the 1,4-adduct of carbonyl compounds ever a major product over the 1,2-adduct?

If, say, propenal undergoes nucleophilic addition of hydrazine, will the 1,2- adduct or the 1,4-adduct be preferred? Why? There is an obvious reasonace structure with an electrophilic beta carbon so ...
-1
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0answers
31 views

What would the transition state look like for the following reaction? And a question on Gibbs free energy of the Transition State [on hold]

The alkaline hydrolysis of ethyl acetate. Also wanted to know whether the addition of solvent would have an impact on the Gibbs free energy value of the Transition State since the transition state ...
3
votes
0answers
28 views

What is meant by pure solids or pure liquids? [duplicate]

In by book, under the topic Heterogeneous Equilibrium it is given For pure solid and pure liquid, active mass is taken to be unity, i.e., 1 as they remain constant throughout the reaction. Could ...
1
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0answers
20 views

Why is the Ionization Energy of Germanium less than that of Silicon?

I've read that in the 13th period, Ga has higher I.E. than Al because of the filling of the d-orbitals in Ga. The text said they have low penetration,hence they don't shield well and the effective ...
4
votes
1answer
20 views

Role of THF in oxymercuration of alkenes

I am trying to self learn solomon's organic chemistry book, but there is no explanation over why we should use THF in oxymercuration. After a quick search I found out that THF help stabilize in ...
1
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0answers
23 views

Measuring change in concentration of hydrogen peroxide

I am conducting an experiment to find the rate constant of the decomposition of hydrogen peroxide, $\ce{H2O2}.$ For this, I was planning on using the integrated rate law: $$\ln(\text{final ...
2
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0answers
16 views

Cleaning of chlorbutyl plungers

This is my first post, so please bear with me. At work I have some chlorobutyl plungers that I need to clean from any residual material that might be left after production. A colleague of mine told ...
-2
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0answers
23 views
0
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0answers
14 views

Ratio of Total energy to Kinetic energy in hydrogen atom when the reference is changed

If in the hydrogen atom Potential Energy at $\infty$ is chosen to be $13.6$eV then the ratio of Total energy and Kinetic Energy(with the sign) for $1$st Bohr Orbit is? My Attempt I just simply gave ...
1
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0answers
30 views

Doubt in a question related to electronic transitions in Bohr's orbits

Question In Bohr series of lines of hydrogen spectrum, the third line from the red end corresponds to which one of the following inner-orbit jumps of the electron for Bohr orbits in an atom of ...
1
vote
1answer
39 views

Why potential energy is neglected in this problem for calculating the energy difference between two stationary Bohr Orbits? [on hold]

Question An electron in a hydrogen like atom makes a transition from a state in which its de-Broglie wavelength is $\lambda_1$ to a state in which its de-Broglie wavelength is $\lambda_2$, then ...
-1
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0answers
30 views

Does the rusting of iron occur underground? [on hold]

Surely there is no pure oxygen gas underground for the oxidation of iron to occur? There are oxides underneath, I believe, but can these oxides cause rusting to occur to?
-1
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0answers
15 views

Seeking direction on who to contact with regards to a flexible (stretchy) but rigid material or polymer that does not fold? [on hold]

I'm looking for a flexible metallic (or other-wise) material that has the ability to be stretched along one or two axis, but rigid enough that it cannot be bent or folded. If this is not the right ...
1
vote
2answers
49 views

Can I normalize my data in order to compare it?

I have three chromatograms of the same eluted protein but at different concentrations, since it got diluted during purification process) and hence peak maximums at very different absorbances. The ...
-3
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0answers
20 views

Kinetics question [on hold]

Im giving a reaction A + B -> C I know the initial concentrations of A, B and C and the rate constant is 1.5 * 10^4 M^-1 s-1 Im tasked to find out the concentration of C after 10 seconds. My ...
2
votes
0answers
25 views

Why would the first Tg be higher than a rescan Tg of an epoxy by DSC? [on hold]

I have some small cured epoxy shafts I am cutting segments out of for checking Tg by DSC. First scan gave a Tg of 118 °C, follow on was 109 °C. Scans were repeated on a new sample of the shaft with ...
3
votes
1answer
29 views

What are the equations giving the molar flow of different molecules linked by a reaction?

Let consider a steady state CSTR in which occurs the following reaction: $$\ce{aA + bB \leftrightarrow cC}$$ Notations: $F_i$ is the molar flow of $i$, $r$ is the rate of reaction, $V$ is the ...

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