All Questions

30,005 questions
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Ion Selective Field Effect Trabsistor (ISFET)

We have project in which we need to determine and measure soil nutrients (N, P, and K), using the ISFET. Our problem is that the ISFETs we foubd were just set to measure soil ph. Is there a way to ...
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What's the difference between ΔG° and ΔG°'

In biochemistry contexts, one often sees $\Delta G^{\circ\prime}$ ("delta G naught prime"), rather than the normal standard free energy change $\Delta G^{\circ}$ ("delta G naught"). What's the ...
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How do scientists study liquid tungsten?

Inspired by this What If article: https://what-if.xkcd.com/50/ In the above article, Randall Munroe mentions that liquid tungsten is difficult to study because of its extremely high melting point. ...
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Beer's law with a polychromatic light source

As is well known, Beer’s law (aka the Beer-Lambert law, among others) is predicated on a number of conditions, one of which is that the light source be monochromatic or, as a practical approximation, ...
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Quadrupole MS: mass as a function of voltage

Every time I see an article about Quadrupole MS (e.g. here), they give formulas like: $$a_x = \frac {8eU} {m r_0^2 \Omega^2}$$ and $$q_x = - \frac {4eV} {m r_0^2 \Omega^2}$$ I suppose the ...
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Where did the bomb calorimeter get its name from?

Is it because it is designed to contain combustions reaction with large pressure increases?
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What kind of bonds (σ or π) are formed by px, py and pz orbitals?

Our chemistry teacher said that two $\mathrm{p}_z$ orbital only form sigma bond whereas two $\mathrm{p}_x$ and two $\mathrm{p}_y$ orbitals form only pi bond. He also stated that only $\mathrm{p}_z$...
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What is the correct reactant in this equation? What is the correct equation?

So I m working in a lab project, i which I did the following step. Sodium hydrogen phosphate (Na2HPO4) is acidified with nitric aid (HNO3) and later reacts with zirconyl chloride (ZOCl2). I wrote ...
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Does an increase in pressure necessarily lead to an increase in temperature?

Ideal gas law says that $pV = nRT$. So with compression, one way to add pressure which makes the volume smaller, can you actually increase the temperature? It does not make sense to me that you can ...
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What is the formula for evaporation rate of water?

I did my own research, and according to The Engineering Toolbox,the formula for the evaporation rate of water is as follows: $\mathrm{gh = Θ A (x_s - x)}$ $\mathrm{gh}$ = amount of evaporated ...
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Why are atomic radii calculations all over the map?

If you look up an element on Wikipedia, it will list covalent, ionic, Van Der Waals, high-and-low -spin, and finally 'empirical atomic radius'. Then, on the page for atomic radius, the chart of '...
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Why is the ionization energy of thallium less than that of lead?

Does lanthanoid contraction not affect the ionization energy trend of thallium, lead, and bismuth? My book says the trend for ionization energy is Tl< Pb< Bi.
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Is there any bad side effects for using calcium chloride to replace a running dehumidifier?

My dehumidifier costs to much to run, so I’m thinking about using calcium chloride to keep my basement dry(er) ALSO, this may keep my mouse problem to a minimum... my questions are -Will this be ...
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When are transition state's energy barrier “reasonable” at a certain temperature?

Every computational chemist who does a little bit of mechanistic studies has asked himself this question. When you obtain your first transition state and look at the activation barrier needed to ...
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What are the limitations of the Theorem of Corresponding states?

I recently came across the theorem of corresponding states, which states that all gases exhibit the same compressibility factor, under same reduced pressure and temperature (and also the critical ...
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Question about extraction of metal [on hold]

I am a junior chemistry learner and I would like to ask why we can extract molten sodium chloride by electrolysis, but we can't extract sodium chloride solution by electrolysis?
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Is any symmetry element conserved during a supra-antarafacial cyclo addition of two cis-butadiene units

I tried to construct a correlation diagram for the [4+4] cyclo addition of two cis-butadiene units. But i failed to construct any meaning full orbitals for the "educt" side where the two butadiene ...
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Balancing chemical reactions, issues of Gauss's elimination method [duplicate]

I am trying to balance some chemical reactions by using the Gauss' elimination method and I noticed that this method does not work if the creation of a matrix with exactly one degree of freedom is not ...
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What drives vibrational cooling in an excited stated?

As we excite a molecule from its ground state, $S_{0,v=0}$, to some excited state in a higher vibrational state, i.e. $S_{1,v'=3}$, what drives vibrational cooling within that excited state manifold (...
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What makes determining entropy changes theoretically so hard compared to enthalpy?

It is really hard to determine the entropy change of a reaction accurately because of subtle solvent effects and a lack of standard entropies. On the other hand, enthalpy is relatively easy and ...
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The Trend Between Boiling Point and Solubility in Organic Chemistry

Is it true in assuming that a higher boiling/melting point means that an organic compound will be more soluble in water?
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What chemicals are in anesthetic drugs [closed]

What chemicals are there in an anesthetic drug and how it reduces the pain of a person? Are the chemicals used in it safely, dangerous or both?
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Is identifying a chemical equivalent to be able to produce it?

This question is a follow up of another thread, where we are discussing Theresa May's accusation of the Russian government which is supposedly behind the recent chemical attack in the UK. Soon after ...
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I found instructions on how to make nerve gas. Is it possible to be real? [closed]

I just happened to find instructions how to make nerve gas. I found it on the Deep web. And since I know next to nothing about chemistry, I'm gonna ask here: Is it possible to make nerve gas ...
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Mustard gas hydrolysis (at a very high rate)

Explain mustard gas hydrolysis at a very high rate: $\ce{Cl-CH2-CH2-S-CH2-CH2-Cl}$ I tried searching online but did not find this reaction anywhere. Can someone explain me the steps/mechanism of ...
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Can carbon monoxide become entrained in water, and will it affect the pH of that water? [on hold]

A hot gas containing $\ce{CO2}$ and $\ce{CO}$ will pass through a water cooler. I know that $\ce{CO2}$ can be dissolved in the water, form carbonic acid, and lower the $\mathrm{pH}$ of the water. Will ...
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Reaction rate of Mg with aryl halides

I have been thinking of the rate of reaction of aryl bromide and aryl chloride with $\ce{Mg}$ to form Grignard. When considering the electronegativities the carbon in aryl chloride is more ...
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Is fluorine also hybridised in carbon tetrafluoride?

I had read that when an atom forms multiple bonds, it hybridises it's orbitals to minimise the repulsion and decrease the overall energy. But do the terminal atoms also exist in hybridised form? E.g. ...
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Calculating amount of base needed to achieve a specific pH in a mixed ethanol-water solvent

I'm looking for some way to calculate how much base I will need to add to an unbuffered solvent consisting of a mixture of ethanol and water in order to basify it to a specific reading (10) on an a pH ...