All Questions

-1
votes
0answers
3 views

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 ...
10
votes
1answer
92 views

Would cerium(III) in solution be oxidized to cerium(IV) in ESI mass spectroscopy?

During ESI (assuming positive ion mode for now), we apply a strong voltage ($1.0{-}\pu{5.0 kV}$) to induce ionization. Therefore, it is common to see oxidation of metal ions (e.g. $\ce{Cu^{+I} -> ...
19
votes
1answer
9k views

Stability Comparison between the Tropylium and Tricyclopropylcarbinyl Carbocation

Why is the Tropylium carbocation less stable than the tricyclopropylcarbinyl carbocation? The tricyclopropylcarbinyl carbocation undergoes a sigma-tropic rearrangement whereas tropylium is highly ...
5
votes
1answer
3k views

Why is oxygen paramagnetic?

Paramagnetic molecules are molecules that have single electrons. When I draw the lewis structure of $\ce{O2}$, it appears to be a diamagnetic structure. What makes it paramagnetic?
0
votes
0answers
18 views

How many resonance structures does 1H-phenalene have?

How many resonance structures does $\ce{C13H10}$ have? I started drawing some structures, but I realized the second and fourth one don’t work because the hybridization is changed on the bottom ...
1
vote
0answers
9 views

Which molecule has maximum bond angle amongst BF₃, BCl₃ and BBr₃?

$\ce{Br}$ is the least electronegative from the given compounds. So, in $\ce{BBr3}$ the electrons will be the closest towards boron and thus due to electron-electron repulsions $\ce{BBr3}$ will have ...
-1
votes
0answers
28 views

Is it possible to dissolve concrete with acid

So I have this question. Can you dissolve concrete with acid? I know that there are many types of concrete, but the common and dominant component, as far as I know, is $\ce{Ca3SiO5.H2O}$ (hydrated ...
0
votes
0answers
8 views

Electronic configuration in [Ni(CN)4]2-

$\ce{[Ni(CN)4]^2-}$ is a low spin , inner orbital complex having $\mathrm{dsp^2}$ hybridisation. According to Crystal Field Theory, $\ce{CN^-}$ is a strong field ligand that causes pairing of ...
2
votes
2answers
103 views

Is Cyclic Ether oxidised by periodic acid

Is three member ring of cyclic Ether oxidised by periodic acid? As this also has oxygen attached to adjacent carbon so i think that Cyclic Ether of three members should be oxidised by periodic acid. ...
0
votes
0answers
10 views

Prove that idempotency is a necessary and sufficient condition for a densiy matrix to be N-representable

As I understand, a necessary and sufficient condition for a density matrix $P$ to be represented by a wavefunction $|\Psi\rangle$ is that it is idempotent, i.e. $P^2=P$. It is easy to see that if $P=|\...
4
votes
4answers
34k views

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 ...
1
vote
1answer
31 views

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. ...
5
votes
1answer
118 views

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, ...
2
votes
1answer
110 views

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 ...
0
votes
0answers
15 views

Where did the bomb calorimeter get its name from?

Is it because it is designed to contain combustions reaction with large pressure increases?
-1
votes
1answer
28 views

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 $\mathrm{p}_z$...
-1
votes
0answers
18 views

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 ...
3
votes
3answers
24k views

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 ...
2
votes
1answer
3k views

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 ...
2
votes
0answers
28 views

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 '...
1
vote
1answer
50 views

Why are there only 6 series (Lymen, Balmer, Paschen, Bracket, Pfund and H.Davy) in the hydrogen atomic spectrum? Why can't there be more?

The Balmer series, for example, is formed when the electron jumps from $n_2 = 3, 4, 5, \ldots, ∞$ to $n_1 = 2.$ The Humphry Davy series (The last series is formed when electron jumps from $n_2 = 7, 8,...
0
votes
0answers
20 views

Will silicon dioxide react with hydrochloric acid?

I have the following equation, based on the reaction of $\ce{SiO2}$ with $\ce{HF}:$ $$\ce{SiO2 + HCl -> SiCl4 + 2 H2O}$$ I want to know if this reaction is indeed feasible, what conditions may be ...
-2
votes
0answers
27 views

Predicting reaction products [on hold]

Suppose we have some reagents: A,B,C,D... We know their exact formulas and we don't know the structures of molecules. But we know the full energy of each reagent(let's say, from experiment). How can ...
-2
votes
0answers
32 views

Is phosphoric acid is strong acid or weak acid? [duplicate]

Is phosphoric acid is strong acid or weak acid? I read in a book that basicity of Phosphoric acid $\ce{H3PO4}$ is $3$, but besides that it says phosphoric acid is a weak acid. this confuses me. if ...
1
vote
1answer
53 views

Titration of barium(II) hydroxide by hydrochloric acid

$\pu{25 ml}$ of $\pu{0.024 M}$ $\ce{HCl}$ is titrated into a volumetric flask which initially contains $\pu{45 ml}$ of $\pu{0.034 M}$ $\ce{Ba(OH)2}$. Calculate the $\mathrm{pH}$. This is how I ...
2
votes
0answers
190 views

What's causing my plastic fork to break?

This has been a real mystery for me at work. For the past three days I've eaten salads for lunch. I used a plastic bowl with a lid and when I was finished with the salad, I didn't rinse out the bowl ...
-3
votes
0answers
25 views

What is nature of calcium phosphate Ca3(PO4)2? [on hold]

What is the nature of calcium phosphate $\ce{Ca3(PO4)2}$? a)acidic b)basic c)neutral d)amphoteric I know calcium phosphate is produced from phosphoric acid ($\ce{H3PO4}$) and calcium hydroxide ($\ce{...
0
votes
0answers
12 views

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.
0
votes
0answers
19 views

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 ...
7
votes
2answers
128 views

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 ...
1
vote
0answers
21 views

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 ...
-1
votes
0answers
20 views

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?
2
votes
0answers
17 views

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 ...
1
vote
1answer
42 views

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 ...
5
votes
1answer
41 views

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 (...
1
vote
0answers
22 views

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 ...
0
votes
1answer
30 views

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?
-3
votes
1answer
79 views

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?
8
votes
5answers
1k views

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 ...
-4
votes
1answer
155 views

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 ...
1
vote
1answer
883 views

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 ...
0
votes
0answers
32 views

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 ...
0
votes
0answers
30 views

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 ...
-1
votes
1answer
37 views

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. ...
1
vote
1answer
27 views

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 ...
10
votes
1answer
18k views

Why does SO2 have a larger bond angle than H2O, H2S, and NH3

So we have to find which of the follwing compounds has the smallest bond angle: $\ce{H2O}$, $\ce{H2S}$, $\ce{NH3}$, $\ce{SO2}$. So L $\propto \frac{1}{BA}$ where $L$ is the number of lone pairs and $...
2
votes
3answers
59 views

Why protons combined with electrons will release heat? [on hold]

During water electrolysis, the electrochemical reaction on the cathode side can be expressed as protons combined with electrons to form hydrogen. I believe this electrochemical reaction is a heat ...
0
votes
0answers
40 views

Is there a reliable chemical theory that predicts pKa based on structure? [on hold]

Obviously, there are general stability arguments that can be made to estimate relative pKas, such as evaluating the stability of the conjugate base of an acid, or thinking about how polarized the bond ...
2
votes
1answer
27 views

What will be the product ratio if I do chlorination of p-toluic acid?

If I do chlorination of p-toluic acid using Lewis catalyst, e.g. $\ce{FeCl3},$ what will be the ratio of major product to side product? Main product shall be 3-chloro-p-toluic acid and other product ...
-3
votes
0answers
43 views

What is the balanced equation for HNO3+Ag(NH3) 2)?(+ balanced charges)

I need to balance a chemical equation properly for tomo chem class. it is really urgent I appreciate all your help :) The chemical reaction involves a silver ammonia complex that reacts with nitric ...

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