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3
votes
1answer
207 views

Evaporation velocity of ethanol: adding ethanol vapour to a gas mixture

I need to add a known amount of ethanol vapour to a gas mixture (He/Ar). To do that I let the mixture bubble in liquid ethanol kept at a known temperature (14 C). The system is made of a large steel ...
16
votes
1answer
66k views

What is the melting point of diamond?

Textbooks and the online reference differ about this and there are more than two answers.
4
votes
2answers
268 views

Molecule with 13 total electrons

Is there a stable molecule with total number of electrons equal to 13? Molecule can be either organic or inorganic
4
votes
3answers
3k views

Intermolecular forces in secondary amines compared to primary amines

Secondary amines form hydrogen bonds, but having nitrogen in the middle of the chain rather than at the end makes the permanent dipole on the molecule slightly less. The lower boiling point is due to ...
2
votes
1answer
4k views

Is melting of NaCl a physical and chemical process?

If I melt $\ce{NaCl}$, I get a molten salt. This means a liquid formed only by ions ($\ce{Cl^-}$ and $\ce{ Na^+}$). That could mean that the crystal $\ce{NaCl}$ experimented a chemical change: $$\ce{ ...
0
votes
1answer
2k views

How to make Sodium dichromate

I've been trying to make Sodium dichromate $\ce{Na2Cr2O7}$ by following these steps: Dissolve an inox spoon in $\ce{H2SO4}$ Filter the solution Dissolve the obtained sludge in $\ce{NaClO}$ Heat the ...
4
votes
2answers
600 views

Can luciferin + ATP → luciferyl adenylate + PPi be reversed?

Reading about the light emitting reaction of luciferin + ATP, catalysed by luciferase I am confused about the following. On this webpage the partial formula is written as: luciferin + ATP → ...
2
votes
3answers
3k views

Dry ice and acetone

In my organic chemistry class there are several reactions that I’ve been told are generally conducted at $\pu{−78^\circ C}$, which is apparently also the temperature of dry ice in acetone. This is ...
3
votes
2answers
2k views

How can I safely carry out an electrolytic etch on stainless steel without producing relatively harmful by-products?

I propose to carry out an electrolytic etch on a stainless steel plate like so: One of electrodes must be the stainless steel plate which is being etched and the surface layer must be removed. I'm ...
7
votes
2answers
1k views

How to properly denote imaginary magnitudes of vibrational frequencies

Vibrational frequency computations provide the magnitudes of vibrational frequencies for each vibrational mode of a molecule ($3N-6$ degrees of freedom for non-linear molecules and $3N-5$ for linear ...
1
vote
0answers
111 views

About the T-S diagram

Suppose we have a T-S diagram of some vapor thermodynamic cycle , say the rankine cycle , and we are interested for example in the composition of the liquid and the vapor in the middle of the ...
3
votes
1answer
493 views

Protactinium-234 half-life

This is going to seem like a rather daft question, but what is the definitive half-live for protactinium-234 (234Pa)? I'm seeing lots of different answers in various academic papers etc. For ...
5
votes
1answer
2k views

In which state does the bifluoride anion exist?

Statement 1. The $\ce{HF2-}$ ions exist in solid state and also in liquid state but not in aqueous state. Statement 2. The magnitude of hydrogen bonding between $\ce{HF}$ is weaker than that ...
2
votes
1answer
247 views

Solution containing Iodine

The question is:- Iodine dissolves in a variety of solvents forming solutions that are purple, brown or any intermediate shade. This property is due to:- Hydrolysis of iodine ...
1
vote
1answer
2k views

Table Salt vs Kosher Salt difference

Does kosher salt has different structure than regular table salt or it is issue of crystals size? Why some recipies want us to use one instead another?
3
votes
1answer
12k views

aldehydes are easily oxidised but ketones are not

Aldehydes are easily oxidized to carboxylic acid but ketones are difficult to oxidise. Most books say that the hydrogen directly bonded to the $\ce{C=O}$ in the aldehyde is what aids the oxidation ...
3
votes
1answer
5k views

Alcohol irregularities in Hydrogen NMR

We've started learning about NMR in my ochem class and my instructor told us that in Hydrogen NMR an alcohol can have a fairly wide range of possible values - usually from about 2 to 5. He said that ...
0
votes
1answer
165 views

Chemical Potential of Idea gas?

Let's say we have a mixture of different ideal gases. I found that the chemical potential of a single component of the mixture is $$\mu_{i}=g_{i}^{0}+Ln(\frac{f_{i}}{P_{ref}})$$ where $f_{i}$ is the ...
14
votes
3answers
10k views

Do chemists refer to water as “dihydrogen monoxide”?

Is the name "Dihydrogen monoxide" actually what chemists would use to refer to $\ce{H2O}$ (assuming there was no common name, "water")? Of course, this is all over the internet. I'm a little ...
2
votes
1answer
324 views

name of a pharmaceutical drug used in dentistry that has Ionic bonding? and how this bounding is made?

Hello I am looking for this information and I did not find anything, the closest thing I have found it is Fluorocarbon, but I think it is wrong, does anybody know?. Help really appreciated I am still ...
3
votes
1answer
5k views

Alkene reactions with sodium tert-butoxide and CHBr₃

This problem has been troubling me a little bit. So in this problem they gave me some reagents and they want me to figure out the end product. The reagents given are: 2-butene reacting with sodium ...
1
vote
1answer
251 views

What is made at the copper cathode when electrolyzing water?

I just electrolyzed water with $\ce{NaHSO4 -> HSO4- <=> H+ + SO4^2-}$ with copper electrodes. At the anode this reaction happened: $\ce{Cu -> Cu^2+ + 2e-} \hspace{26 mm} E_0 = -0.34V$ ...
2
votes
1answer
1k views

What is the difference between the roles of a surfactant and a stabilizer in the process of nanocrystal growth?

The crystals that I am synthesizing use two different stabilizers CTAB and SDS, but they say one is used as a surfactant and since they are both stabilizers what is the need for both?
1
vote
1answer
2k views

How do I determine the equilibrium concentration given Kc and the concentrations of component gases?

I feel my method for solving it is correct and I've checked my calculations yet I can't get the right answer. Nitrogen and oxygen gases may react to form nitrogen monoxide. At 1500 °C, $K_c$ equals 1....
1
vote
2answers
3k views

What does negative pressure mean in the context of this manometer?

I have a basic question on a closed manometer: I see that in this case the pressure of gas is lower than that of the liquid, which is why the liquid is higher on the left side. Now, what I don't ...
2
votes
2answers
240 views

What is Bisphenol A used for?

I am trying to find out what BPA is used for in the industrial production of plastics. On sources such as Wikipedia I only found the information that it is used, but not why. What are the advantages ...
2
votes
1answer
74 views

Polymers with no molecular mass distribution?

What sort of ideal conditions are required - theoretically - to conduct polymerization reactions to make all the macromolecules end up with exactly the same molecular mass, just like the products in ...
0
votes
1answer
165 views

How to determine the reaction of a strong electrolyte? [closed]

I'm told the $\ce{KMnO4}$ is a strong electrolyte. How can I figure out how the reaction looks like?
22
votes
2answers
3k views

Electrophilic Aromatic Substitution: Are protonated OH-groups ortho-/para- or meta-directing?

In Electrophilic Aromatic Substitution ($\text{S}_{\text{E}}\text{Ar}$) reactions groups that can donate an electron pair into the aromatic ring, e.g. $\ce{-OH}$ or $\ce{-NH2}$, are ortho-/para-...
14
votes
4answers
26k views

How explosive is hydrogen gas?

I want to electrolyze water to get oxygen and hydrogen. I want to mix them in a regular balloon and ignite it. How much hydrogen would you need in a 2:1 ratio with air for it to be dangerous? Is this ...
4
votes
2answers
11k views

Why does adding an acid speed up electrolysis of water?

I've read in several places that when electrolyzing water into $\ce{O2}$ and $\ce{H2}$, that adding a salt or an acid will speed up the process. Why is this?
2
votes
1answer
114 views

Is there a danger in electrolyzing NaCl?

To make $\ce{NaOH}$ one could electrolyze a solution of $\ce{NaCl}$ in water ($\ce{H2O}$) It would go like this: $$\ce{2H2O_{(l)} + 2Cl-_{(aq)} + 2Na+_{(aq)} -> H2_{(g)} + Cl2_{(g)} + Na+_{(aq)} + ...
6
votes
2answers
15k views

How does voltage and resistance affect an electrolysis?

At school we've learned about calculating the voltage needed to perform an electrolysis. The current is how many electrons pass per time. The formula is given $$I = \frac UR$$ This means that given ...
11
votes
2answers
142k views

What are the products of the dissociation of sodium bicarbonate in water? What is the relative pH of the solution?

I had a recent question on a test that asked what the products would be if sodium hydrogen carbonate were dissolved in water. I had a few candidate answers $\displaystyle\ce{NaHCO3 -> Na+ + HCO3-}$...
-2
votes
1answer
774 views

How alkanes can be prepared by aldehydes and ketones? [closed]

Preparation of alkanes by aldehydes and ketones, its chemical reaction and mechanism.
-2
votes
1answer
298 views

Radial expectation value for particle in a cubic box [closed]

A hydrogen atom is in a cubic box with side lengths equal to $\require{mediawiki-texvc}\pu{100 \AA{}}$. For what value of $n$ (principal quantum number) will the expectation value of the radius be ...
2
votes
1answer
3k views

Reaction of sodium dihydrogen phosphate and ammonium chloride

I have a homework question that says Write an equation when $\ce{NaH2PO4}$ and $\ce{NH4Cl}$ are mixed. I assume that this is an acid base neutralization and will probably also give a salt due to ...
2
votes
1answer
541 views

Determining order of a reaction without isolation

I'm writing a computer program to calculate the order of a chemical reaction with respect to each reactant. When I do this by hand, it's easy to isolate which reactant concentration stays relatively ...
2
votes
0answers
113 views

Why does confinement of quantum dots result in discrete energy levels?

I'm doing a project with lead (II) sulfide quantum dots because they have optical transitions in the near infrared. I understand the simple "particle in a box" approach where confinement strengthens ...
7
votes
1answer
1k views

What is the reason a grain of salt alters the perceived bitterness of coffee by such a high degree?

Coffee served hot can be quite bitter (presumably high pH). Several people I have known will add a single grain of salt to the coffee - which reduces the perceived bitterness. My question is: What ...
1
vote
1answer
3k views

Limiting Reactants without a given mass

This is a question I have for Chemistry homework, but I don't understand how to solve it without a given mass. I narrowed the choices down (see below _) I know a limiting reactant well limits the ...
1
vote
2answers
7k views

What are the main differences of CTAB and DTAB surfactants? And what are practical applications of them?

Just doing a little bit of research of both surfactants but I can't seem to find too much online about them. Hopefully you guys can help out!
1
vote
1answer
128 views

How to make something solid that dissolves faster than bar soap in water

What is a soap-like material that holds a solid shape, but dissolves completely in water over 10-15 minutes. Think disappearing Rubber Ducky.
3
votes
3answers
14k views

why CO2 is not organic [duplicate]

this might be very childish question but i am comfused because they say that organic molecules are those that contain H and C if that is so how can you call carbontetrachloride organic, even it hasn't ...
3
votes
2answers
276 views

Can we goldify metals?

I've read in some book that one of the old chemists was able to transform cheap metals into gold. I know that gold is an element (Au) so we can't transform a metal into Au. But as I read further it ...
2
votes
1answer
81 views

Figuring out the concentration of weak polyprotic acids in presence of strong acid

We have a $\rm{0.1 \ M}$ solution of $\rm{H_2S}$ with a $\rm{0.1 \ M}$ solution of $\rm{HCl}$. We need to figure out the concentration of $\rm{S^{2-}}$ ions at equilibrium. $$\rm{H_2S \...
14
votes
1answer
11k views

Why does acetylene, having an acidic proton, not react with strong bases like NaOH and KOH?

In acetylene (ethyne, HC≡CH), the carbons are sp-hybridised, which make the attached protons more acidic than those in alkenes or alkanes. (See also: Relative acidities of alkanes, alkenes, and ...
-1
votes
1answer
870 views

Effect of periodic acid on trans diols of 3, 4 and 5 membered rings [closed]

Does periodic acid cleave the following diols? trans-cyclopropane-1,2-diol trans-cyclobutane-1,2-diol trans-cyclopentane-1,2-diol
5
votes
2answers
188 views

Getting to use the lab! [closed]

Today I finally mustered the courage to go and talk to the director of the labs to politely ask him if I could use the labs out of class hours. Long story short, our lab sessions "are bad" because we ...
2
votes
2answers
4k views

Reaction between zinc and sulfur

Would the reaction between zinc and sulfur be $$\ce{Zn_{(s)} + S_{(s)} -> ZnS_{(s)}}$$ or $$\ce{8 Zn_{(s)} + S_8\ _{(s)} -> 8ZnS_{(s)}}$$ I know that $\ce{S}$ and $\ce{S8}$ are allotropes of ...

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