All Questions
41,151
questions
0
votes
0
answers
36
views
Proof of aromaticity and antiaromaticity from generalised eigenvalue equation
In a molecule such as cyclobutadiene, 2 of the 4 molecular orbitals are half fulled nonbonding MOs, reducing the strength of the bond, the same is true for cyclooctatetraene and other 4n molecules. On ...
3
votes
0
answers
23
views
Why does the equation for chemical potential apply to liquids and aqueous solutes?
The equation for chemical potential of a gas can be derived as such:
At constant temperature,
$$\mathrm dG = V\,\mathrm dP \label{eqn:1}\tag{1}$$
Substituting with the ideal gas law $PV = nRT$,
$$\...
- 334
1
vote
0
answers
17
views
Are there any types of adhesive which are designed to be easily soluble in strong acid (HCl with pH 1-4)?
I am a mechanical engineer so forgive my ignorance in chemistry. I know there are water soluble adhesives like polyvinyl alcohol but I am wondering if there are glues which easily dissolve in low pH ...
- 11
5
votes
1
answer
160
views
Why does band heads arise in vibrational-rotational spectra?
I learn that a band head is a region of maximum intensity due to many lines falling together. It can be determined by differentiating the expression for the R branch.
To no avail, I cannot find any ...
- 165
-1
votes
3
answers
51
views
forces between aldehydes and water molecules
How is it that aldehydes cannot form hydrogen bonds with each other but can with water molecules. Shouldn't there only be dipole-dople forces?
4
votes
0
answers
36
views
Rate of polymerization for copolymers with two monomers
I've found in textbooks that for a chain growth homopolymerization the rate of polymerization $r_\mathrm{p}$ is
$$r_\mathrm{p} = k_\mathrm{p}\sqrt{\frac{f_\mathrm{kd}}{k_\mathrm{t}}}c_\ce{A}^ac_\ce{B}^...
- 81
0
votes
1
answer
84
views
Cubic nature of van der Waals' gas equation
$V_m^3-\dfrac{RT+bP}{P}V_m^2+\dfrac{a}{P}V_m-\dfrac{ab}{P}=0$
So, At $T<T_c$ the above equation has three real roots say $V_1,V_2,V_3$, my doubt is what does this mean physically because for some ...
- 119
0
votes
0
answers
21
views
How many hydrogen environments are there in phenyl acetic acid? [duplicate]
How does the molecule below have only three hydrogen environments? Should it not have 5 different hydrogen environments according to the labelled diagram?
1
vote
1
answer
51
views
How does coenzyme A produce proton from pyruvate ions?
Coenzyme A (CoA) is a complex molecule consisting of mercaptamine, β-alanine, pantoic acid, diphosphate, pentose, phosphate and adenine moieties:
Which part of it actually plays role in the formation ...
- 355
0
votes
0
answers
16
views
How is the cubic d-spacing formula derived from the Miller indices of a standard plane? [duplicate]
I just had a question about deriving the cubic structure d spacing formula. Just trying to work through the logic so I understand it better.
If I start with the standard plane:
• The plane ...
- 33
-1
votes
0
answers
46
views
Comparing bond strength by overlapping of orbitals
Consider C-Cl and H-Cl bonds :
Electronegativity difference in C-Cl bond = 0.6
Electronegativity difference in H-Cl bond = 0.95
This suggests that H-Cl bond is more polar than C-Cl bond, but not very ...
- 17
-4
votes
0
answers
31
views
Is liquid carbon tetraflouride a good solvent? [closed]
At temperatures of of -180 to -130 Celcius, where carbon tetraflouride is in a liquid state, is it a good solvent?
-1
votes
0
answers
27
views
quatum mechanics - calculating the initial photon wave length due to given data [closed]
the question is a part of a chemistry course with the subject of quantum mechanics and concretely the quantum model and the photoelectric effect:
On the image illustrated a graph which describes the ...
- 99
-3
votes
0
answers
12
views
Will the amount of the salute needed to produce a saturated solution be the same for different solutes [closed]
this type of question is a question in natural science and technology subject. It's about solvents solutes particles soluble and Solutions (as in a mixture).
-5
votes
0
answers
25
views
Discovery of aspirin [closed]
In our school textbook there is a small discussion about aspirin, its structure and its synthesis from salicylic acid. But what has always fascinated me is its chemistry. I mean how scientists were ...
- 140
-4
votes
0
answers
59
views
Exhaustive explanation of all electrochemical processes occurring during electrolysis of copper sulfate solution
I’m trying to gain a comprehensive understanding of what chemically occurs during the electrolysis of copper sulfate solution using copper electrodes.
Some resources say only copper is deposited on ...
2
votes
1
answer
157
views
Understanding the molar free energy to simulate phase separations (Na2O-SiO2)
I am a mathematician and I want to understand the molar free energy model given in Kim and Sanders (2020) Equation (1), that is,
\begin{equation}
f(c,T) = RT \big(c \log(c) + (1-c) \log(1-c)\big) + \...
- 23
-3
votes
0
answers
13
views
How to measure EC/ TDS?
I would like to measure the electrical conductivity of my hydroponic resovoir, with a EU plug, temperature sensor and an Arduino. I know that it is not accurate, because it will polarize, but this ...
-2
votes
0
answers
42
views
Can iodide (I- ion) act as an oxidising agent? [closed]
I have this chemistry question that says iodide can act both as an oxidising agent and reducing agent. Now I understand how it can reduce something else by losing electrons going through oxidation ...
-6
votes
0
answers
43
views
If we can see things lightyears away with telescopes, why can't we observe atoms? [closed]
Just wondering, since telescopes are seemingly so much more powerful than microscopes.
3
votes
0
answers
68
views
Acidification of a vicinal diol [duplicate]
The following is a question from Advanced problems in organic chemistry by MS Chouhan:
The options given are:
My initial thought was that this could be a pinacol–pinacolone rearrangement. However ...
- 101
1
vote
0
answers
39
views
Comparison of boiling points between 2‐butanol and isobutanol
Which has higher boiling points among butan‐2‐ol (1) and 2‐methylpropan‐1‐ol (2)?
I know that branching decreases the boiling points, but I want to know how position of substituents affects the ...
- 27
-2
votes
0
answers
38
views
How does s subshell not have a node in the center despite the nucleus being there?
In most images of 1s subshell I see that there's no node shown at the center, and even the formula n-l-1 gives 0 as the answer.
But, isn't the nucleus ...
- 5
-2
votes
0
answers
20
views
Rate of reaction between sodium thiosulfate and potassium permanganate
I plan to study the rate of reaction between sodium thiosulfate and potassium permanganate using a colorimeter. However, does anyone know if the reaction is instantaneous or not? If so, can the rate ...
- 107
-2
votes
0
answers
15
views
Transition metals [closed]
Similar to the halogen that decrease in reactivity down the group, what is the trend of reactivity for transition metals? What makes a transition metal more reactivity, and why does this occur in ...
-3
votes
0
answers
29
views
thermodynamic equilibrium
A thermodymic system is said to be in equilibrium if it satisfies the two conditions :
1-The system’s macroscopic properties remain constant with time.
2-removal of the system from contact with its ...
- 95
0
votes
0
answers
42
views
Does vinyl chloride have greater electrophilic addition rate than ethene? [closed]
Which of the following will have a greater rate of electrophilic addition?
Since the rate of electrophilic addition AdE is proportional to nucleophilicity of the substrate, I assume chloroethene $\ce{...
- 9
-3
votes
0
answers
11
views
Enthalpy of Solution of Calcium Chloride with Different Concentrations of Aqueous Sodium Chloride
Imagine an experiment. You have a solution of aqueous sodium chloride. You drop calcium chloride in and measure the temperature change, which you use to calculate the enthalpy of solution. You repeat ...
- 1
-2
votes
0
answers
35
views
Meso Compound and Internal Line of Symmetry
Hey everyone:)
I'm only learning orgo this year so please keep it relatively light!
I am reviewing Meso compounds with a video by the organic chemistry tutor, where he draws the two molecules on the ...
- 1
-1
votes
0
answers
36
views
Chemists out there how do you find specific solublity data for a given compound?
For example I am interested in the solubility of 1,3,5-Trichloro-1,3,5-triazinane-2,4,6-trione in dioxane. Is there some chemical database or website that contains this information?
- 1
-1
votes
0
answers
17
views
What is synthesizing PTMA and polymer oxidation?
Here is an excerpt from the organic radical batteries Wikipedia page:
Free-radical polymerization as a synthetic approach has several drawbacks. The most relevant limitation is the fact that ...
- 1
-2
votes
2
answers
32
views
Information about liquefied carbon factories from carbon dioxide
I am looking for some information about the factories that turn CO2 gas into the liquid CO2. I want to know the methods that they are using. Can anyone help me?
Thanks
- 1
1
vote
2
answers
39
views
How does the redox reaction in a voltaic battery pile start?
From the Wikipedia article, the redox reaction for a voltaic pile is:
\begin{align}
\text{Oxidation:} && \ce{Zn &-> Zn^{2+} + 2e^-}\\
\text{Reduction:} && \ce{2H^+ + 2e^- &-&...
- 119
3
votes
0
answers
61
views
Calculate frequency dose from different light intensities
The quantum yield for homolytic O-O cleavage of (CH$_3$)$_3$COOC(CH$_3$)$_3$ at $266$ nm is $0.21$. In one experiment, a pulsed laser of this wavelength was used to induce the formation of t-butoxyl ...
- 671
-2
votes
0
answers
19
views
Why ZnO is good photocatalyst? [closed]
Why ZnO is good photocatalyst for degradation of organic dyes (like methylene blue)?
I know about for the wide band gap, but if you know something more.
- 1
-3
votes
0
answers
31
views
Why do we implant ions in ZnO and TiO2 nanostructured films? [closed]
Do you know why we "put" ions (like Ag+ for example) in ZnO or TiO2 nanostructured films (which are photocatalysts)?
When we inmpalnt ions, ZnO become better photocatalyst. And I do not ...
- 1
-1
votes
0
answers
25
views
Rate of solvolysis for given allylic chlorides [closed]
We clearly have to judge the resulting carbocation stability in this question and that's what I tried doing.
(I) results in a primary allylic carbocation in both possible resonating structures.
(II) ...
- 1,096
-1
votes
1
answer
45
views
Does nickel precipetate gold and copper?
I dissolved some CPU s and RAM s in aqua regia the day after I found a green solution with black powder in the bottom. So what just happened is it nickel or tin from solder?
- 17
-1
votes
2
answers
35
views
Displacement Reaction [closed]
In a displacement reaction I understand that the more reactive metal essentially takes the place of the less reactive metal. But I can't seem to understand how this more reactive metal can break the ...
-3
votes
0
answers
22
views
Calculating Coordination Number in Solid State
i)For c.n of a cation can we consider another cation as the nearest ion(in c.n) suppose it is nearer than the anion?
ii)For finding c.n of tetrahedral voids the distance from the tetrahedral void to ...
- 1
-1
votes
1
answer
46
views
Calculating Enthalpy Change from Calorimetry [closed]
What calculating the enthalpy change of a reaction, for example 5g of CaCl2 dissolving in 100 mL of water, is m the mass of water or the mass of water plus the mass of the salt.
q = (105g)(4.18)T
or
q ...
- 17
1
vote
0
answers
29
views
What is the black sticky residue after heating copper hypophosphite?
I am experimenting with double sided PCB (printed circuit board) via (connections from one side to the other) holes activation.
The activation is the process of making the walls of holes electrically ...
- 111
0
votes
0
answers
10
views
How to get hydrogen indices in RDKit subtruct matches [migrated]
I am searching for functional groups in RDKit molecules and want to get the corresponding atom indices. Using GetSubstructMatches() however does not return some (...
- 1
-1
votes
0
answers
22
views
Trying to understand boiling in ideal solution
I have studied that the boiling point of a pure liquid is the temperature when it's vapour pressure becomes atmospheric pressure (or the pressure of its surrounding in general). But I didn't ...
- 99
0
votes
1
answer
66
views
Determining the average relative mass of an element from the percentage of isotopes
Suppose we have an element $\ce{A}$. Its relative mass is $16$ and it has three isotopes: $\ce{^16A}$ ,$\ce{^17A}$ and $\ce{^18A}$. The available percentage of $\ce{^17A}$ is $0.037\,\%$. What is the ...
- 11
-2
votes
0
answers
61
views
Oxidation States: The question which just never seems to be properly answered [duplicate]
Take the reaction of hot, concentrated NaOH and Cl2: 3Cl2 + 6NaOH --> 5NaCl + NaClO3 + 3 H2O. The chlorine starts off with 0 oxidation state and then undergoes disproportionation to form 1- state ...
- 130
-1
votes
0
answers
33
views
Thermometric titration for a graph of temperature against volume of titrant
Why would you extrapolate the two best fit lines up to the point where they intersect?
Image Source- Wikipedia
I know that this is the endpoint where all alkali or acid is neutralized (or just when ...
-2
votes
0
answers
28
views
Oxidation of different metals
I am trying to understand the Lavoisier and Priestley experiments on oxygen. The last one heated mercury oxide and the merury gained its pure form and reduced. Lavoisier heated mercury and obtained ...
1
vote
0
answers
27
views
Why probability for an atom is fraction for population?
In the canonical ensemble the probability of finding an atom (or molecule) in its $i$-th energy state is given by the Boltzmann factor.
This probability is interpreted as the number of microstates ...
- 698
-1
votes
0
answers
19
views
Voltage required for electrolysis of molten Cu2O feedstock
Would someone mind clarifying the overpotential voltage required for molten Cu2O.
Looking at Redox charts all Oxygen reactions use hydrogen or other atoms or molecules.
The goal is to calculate the ...