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3
votes
1answer
83 views

Electrochemical characterization of benzenesulfonamide

I'm trying to elucidate current peaks for benzenesulfonamide, using an acetic acid-sodium acetate 0.1M buffer at pH 5.5 as electrolyte. When doing cyclic voltammetry, I get a voltammogram similar to ...
14
votes
2answers
19k views

Why are fluorides more reactive in nucleophilic aromatic substitutions than bromides?

In nucleophilic aromatic substitution reactions, why do fluorides react faster than bromides? Ordinarily bromide is a better leaving group than fluoride, e.g. in $\mathrm{S_N2}$ reactions, so why isn'...
1
vote
0answers
202 views

bond energy calories

I am attempting to optimize interactions for a series of random and test molecules to a protein using docking software. The software uses QM/MMGBSA to calculate free energy in joules (yes it is not a ...
2
votes
1answer
787 views

How does water deionization process work?

What are the technical/scientific details behind the process of water deionization? How does deionization machines like those manufactured by Millipore work?
16
votes
1answer
41k views

How does alum improve the settling of particles to produce 'clean' water?

How does the addition of alum — potassium aluminium sulfate or $\ce{KAl(SO4)2}$ — help settle the dust particles in water? There was such a statement in my Year 9 textbook, and so I was wondering how ...
2
votes
1answer
86 views

Reaction with carbon

Usually maximum time we see then after cooking by gas there is no black spot on the pot. But continually burning can affect the pot surface and makes black powder. My question is: What is the ...
4
votes
2answers
153 views

“Drinking water” plastic - can I store beer in this?

This is an outdoors & chemistry question. I have an old and functional water bladder, shown below. On it, there are markings that coffee, beer, wine, hot drinks etc. must NOT be stored inside, ...
4
votes
2answers
261 views

Material that is flexible when cold but becomes brittle when hot

I'm looking for a material that I can use to make a mesh netting. It should be flexible and have reasonable tensile strength when cold but brittle when hot (>$\pu{400^\circ F}$). I want to use it to ...
9
votes
2answers
44k views

Does an onion completely remove “fresh” paint VOCs and other chemicals emitted?

I have read that paint contains VOCs(Volatile Organic Compounds), and solvents generally, and I could wait for them to dissipate, but i've read there are ways to remove the smell of paint such as half ...
3
votes
1answer
123 views

Less maintenance-dependent continuous pH testing

I am creating an automated chemical component mixing system (DIY project). One of the features required is continuous monitoring of pH value in my main solution. I do not need it to be very precise, ...
2
votes
2answers
202 views

To model early earth chemical reactions which types of reactions should be included?

I'm currently working on building a simulator for the early earth to examine the spontaneous occurrence of food generated autocatalytic sets. No one in my group is a chemist, so the bottle neck for ...
5
votes
1answer
2k views

What is the heat energy required to perform electrolysis equivalent?

The question may be off-topic here. If my concept is flawed, please poke me in the rib (+: Sources on the internet indicate a minimum 1.2Volts is adequate for electrolysis of water; nominally 6V. ...
10
votes
1answer
3k views

How does toluene react at higher temperatures and why?

Reaction of toluene at high temperatures gives us (o-m)toluene; whereas at normal conditions of electrophilic attack, it gives us (o-p) directing. Why does this happen at high temp although as methyl ...
3
votes
2answers
960 views

Bond of interest

What does it mean for our bond of interest if we have low bond length and high frequency? Trying to make this connection but am not understanding. If anyone could explain it intuitively, that would be ...
8
votes
2answers
16k views

Exothermic or Endothermic reactions

Can we determine whether a reaction is endothermic or exothermic? For example if we are given the following reactions: $$\ce{2SO2 + O2 -> 2SO3}$$ $$\ce{H2 + I2 ->2HI}$$ $$\ce{N2 + 3H2 -> ...
-12
votes
1answer
3k views

(Organic Chemistry) Common Atoms in Organic Molecules [closed]

What are 6 atoms commonly found in organic molecules?
3
votes
2answers
185 views

Would dissolving a salt and letting it sit for 48 hours have an effect on the solution?

If one were to dissolve magnesium citrate (about $100~\mathrm{mg}$) in water (about $70~\mathrm{ml}$) and let the solution sit for 48 hours, would the solution be exactly the same as one dissolved and ...
2
votes
1answer
112 views

Cathodic protection of active metals

Cathodic protection prevents the removal of positive form the metal surface by applying a negative charge to the metal. Is is possible to prevent the reaction of an active metal (i.e. sodium) with ...
2
votes
1answer
8k views

What are the oxidation states of sulfur in the tetrathionate ion?

What are the oxidation states of the sulfur in the tetrathionate ion $\ce{S4O6^{2-}}$?
3
votes
1answer
1k views

At what temperature will proteins and fats boil in a vacuum?

A question was asked on another stackexchange site: This is not nice perspective, but eventually it will happen. An astronaut falls out of spaceship because of damage caused by collision with other ...
7
votes
1answer
6k views

How do I determine the crystal field splitting for an arbitrary point group?

How can I figure out the degeneracy of the d orbitals for a site that has a given point group? Specifically I'm interested in $D_{3d}$ and $D_{3h}$, but it would be good to know how to do it in the ...
4
votes
1answer
151 views

Safe, easily detectable gas or aerosol for testing fume hoods

I've recently started undertaking a project to construct a small fume hood. So far I'm considering its use for soldering, 3d printing with ABS and polystyrene, and PCB etching using a muriatic acid/...
5
votes
2answers
746 views

Counting valency of atoms, in a molecule with python

The documentation for the indigo module can be found here http://ggasoftware.com/opensource/indigo/api#inputoutput So for instance if I have a molecule object for some SMILES string, e.g. ...
3
votes
1answer
6k views

What happens in the reaction of ammonium dichromate and mercury(II) thiocyanate?

I found this reaction of $\ce{NH4Cr2O7 + Hg(SCN)2 ->[\Delta]\ ?}$ on youtube, and I'm curious as to how it works. I tried searching online, but didn't find much on it. Thanks.
2
votes
1answer
200 views

What does this scale mean?

$$\log_{10}~\mathrm{pg}/\mathrm{ml}$$ I do not understand the scale. How do I convert this to a standard concentration (without the logs)?
3
votes
1answer
3k views

Why are partial molar Gibbs energy and Gibbs energy per mol equal?

I'm not a chemist, but I need some insight into chemical thermodynamics. In the book that I'm reading (Nevers, 2012), equation (4.28) relates the chemical potential of a pure species to it's Gibbs ...
4
votes
2answers
13k views

Z* effective charge and Ionization Energy

I'm trying to figure out the patterns for Ionization Energies. I am familiar with the periodic trend, however things become quite different when we hit the 1st I.E. For example, Na has an I.E(1) of ...
1
vote
1answer
149 views

Why do batteries specifically vent *hydrogen* in the event of abuse?

When a battery is subject to overcharging or overdischarging (including attempts to recharge a primary cell), it may vent hydrogen. It seems that every type of electrochemical battery I've read about ...
0
votes
1answer
2k views

Can you determine whether a compound can form given particular elements?

Say you are given a set of particular elements, such as Dy, C, I, Er, P. Is it possible to determine whether a compound exists with all of the given elements and no more? If not, is it possible to ...
4
votes
2answers
488 views

Gold nanoparticles in a water/oil environment

I am currently investigating the assembly of gold nanoparticles in a mixture of water and oil. The thing is the following: If we have gold nanoparticles (35nm diameter) dispersed in water and we put ...
5
votes
2answers
2k views

How to determine a Reynolds number for mixture of 2 liquids

I'm experimenting with synthesis in microreactors and I'm using 2 reactants. I'd like to estimate the Reynolds number of the flow containing two miscible fluids. I have the values of their properties (...
4
votes
1answer
3k views

How to measure amount of oxygen (or carbon dioxide) in air?

I'm not chemist, and I'm looking for easiest way to measure how much oxygen plant in closed container will produce per hour [can measure over time for increased accuracy]. My first idea was to ...
4
votes
1answer
278 views

What does an endpoint saturated signal mean. How does it relate to equilibrium constant?

I have had a question that has been bugging me for a couple of years in my graduate school career, and I was wondering if perhaps someone could help explain it to me. Given an endpoint assay like this ...
3
votes
2answers
219 views

Is this relation in case of a mixture of ideal gases valid?

I came across the following relation in a book (written as a fact, with no proof), for a mixture of ideal gases both at the same pressure and temperature. The final volume of the mixture of gases ...
1
vote
0answers
101 views

How to store molecule data using SMILES when building a toy chemistry model

I'm currently building a toy chemistry model based around Gillespie's algorithm. Starting from a food set of {H,O,N,C} I let my system evolve, I have been storing my molecules as strings in SMILES ...
7
votes
1answer
1k views

Which of mono-, di-, triphenylmethane is the most acidic?

Question How would you compare the acidity of the most acidic proton in each of the following molecules? diphenylmethane toluene triphenylmethane The answer says 3 is the most ...
6
votes
2answers
244 views

Removing titanium from tantalum crucible

I'm trying to remove titanium filling from a tantalum crucible for a high-temperature effusion cell. I've managed to get a majority of the material out with tweezers, but some remains and is ...
11
votes
1answer
9k views

Confusion in unit cells of crystal system

Unit cells are divided into two main types Primitive Non-primitive Primitive includes simple cubic lattice whereas non-primitive includes fcc bcc end centered.. Among the seven types of crystal ...
23
votes
2answers
8k views

What does lowercase r-s notation mean?

I came across a naming convention which I haven't seen before. I let ChemDraw name the following compound for me and got a name containing lowercase "r" and "s" configurations. Can someone tell me ...
-3
votes
1answer
404 views

Can anyone tell me the mechanism behind this reaction? [closed]

$\ce{1-octene -> octan-1-ol}$ The reaction occurs in the presence of $\ce{ROOR}$ and $\ce{HBr}$. There is no information about temperature.
2
votes
1answer
100 views

Would cooling of a battery using cooler affect its life time?

My smartphone gets over heated where I use mobile data for long period. Last day I found a cooler of an old cpu, the thing silver in colour to absorb heat(with eventually gives out heat as it has more ...
-5
votes
2answers
857 views

Which compound reacts most slowly? [closed]

I'm trying to figure out why the answer is C. Can anyone explain to me why that is the answer?
4
votes
2answers
5k views

Wave function for particle in a infinite well located at -L and +L

The wave function for a particle in a infinite potential well located at $0$ and $L$ is $$\psi_n=\sqrt{\frac2L}\sin\frac{n\pi x}L$$ I want to find our wave function for the same situation where the ...
9
votes
1answer
848 views

Is it safe to condense water into a liquid nitrogen trap?

I'm trying to remove water from an imidazolium salt (i.e. dry the salt). However I want to know if it is safe to remove the water under vacuum. Is it safe to condense water into a liquid nitrogen ...
2
votes
1answer
3k views

Sigma and pi symbols in molecular orbital theory

In molecular orbitals diagram, sigma ($\sigma$) and pi ($\pi$) symbols are used. What do these symbols really mean?
25
votes
1answer
257 views

When measuring avidity should you use the ligand concentration or the nanoparticle concentration?

Looking at avidity between a ligand-receptor, you're looking at an enhancement of the $K_d$ compared to a lone ligand. Is it more appropriate to compare the $K_d$ using the concentration of the "...
2
votes
0answers
582 views

speeding up etching process of a copper board

Background: I use Sodium persulfate to etch a copper board to manufacture home made Printed Circuit Board (PCB). On the etching powder's plastic, it is written that: 1.5-2dl of etch powder in 1 ...
2
votes
1answer
623 views

Does variations in air pressure affect the melting point of PLA and ABS while 3D Printing?

Tight temperature controls are needed to ensure that the filament used in fabrication does not begin to "ooze". In places where the air pressure rises and drops during the course of the day there may ...
19
votes
3answers
404 views

Open flame combustion in bizarro world

Humans typically achieve combustion by starting a chemical reaction of a fuel (often a carbon $\ce{C}$ containing fluid like methane $\ce{CH4}$), which is is brought into an an oxidizer (a gas ...
29
votes
5answers
110k views

Difference between exothermic and exergonic

In High School I learned that an exothermic reactions releases energy, while an endothermic reaction needs energy to occur. Now I learned that there is a separate, somewhat similar classification ...

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