Raoul Kessels
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Is it possible to calculate the concentration percentage using chromatography paper?
1 votes

Yes, it can be done. I have done it on silica plates to compare the content of a natural product in different samples of plants. It is , obviously, better to use HPLC, but in that case the sample ...

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Racemization of ketones in presence of catalytic acid
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5 votes

You are right that the racemization occurs through the enol form. The chiral center is on the carbon attached to the chlorine atom. In B, that carbon participates in the enol form, but in A not. ...

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Why are copper salts less soluble than zinc salts?
7 votes

It is because the difference in electronegativity. The higher the difference in electronegativity between the cation and the anion, the stronger the ionic bond. Since we are comparing species with ...

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What's this mystery acid?
6 votes

This acid is actually not that concentrated. Suppose it were $\ce{HCl}$, then: $\frac{10^{-0.68}\cdot 36.45}{0.20}\frac{100}{1000}=4\%\ \ce{HCl}$ I am not going to try on my skin but it is not like ...

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Using drip extraction, how much caffeine is extracted from coffee as a function of the amount of water used?
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2 votes

Caffeine has a solubility in water of 20% at 80 $^\circ$C, while the coffee has between 1 and 4% caffeine. That means that you have more than enough water to extract all the caffeine in the coffee. ...

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Methods for dissolving Scotch/Kaptop/etc. Tape for Electron Microscopy?
2 votes

Kapton is a polyimide: It contains an $\ce{N}$ substituted phtalimide as a substructure. This kind of compound is used in the Gabriel synthesis to make primary amines. The synthesis is very ...

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what is the product of this reaction and mechanism?
0 votes

Yes, the oxigen is protonated, water enters, methanol leaves and another $\ce{H^+}$ is released. Then the oxigen of the other $\ce{CH3O}$ group is protonated, the keto group is formed while the ...

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Difference between tendency of benzene and thiophene to undergo sulfonation
4 votes

In the chapter Aromatic five-membered ring heterocycles with one heteroatom in Organic Chemistry by J. William Suggs (2002) the following explanation can be found (pp. 403-404) which summarizes the ...

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How long does it take to saturate H2O with O3
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1 votes

The solubility of ozone in water as per one website is: First thing is to establish which curve you need. In 1 m$^3$ gas you have 70 L ozone: $\frac{70\ L\ \ce{O3}}{1\ m^3}\frac{1\ mol}{0.082\cdot ...

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When there's a photoelectric effect, do the electrons leave altogether or leave one by one?
0 votes

Only electrons that are hit by a photon with the appropriate wavelength will be moved. So that means that they are leaving one by one. This can however ocurr at several places at a time so that means ...

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How to remove nitrose gasses from ozone gas mixture?
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3 votes

There is no need to use caustic since $\ce{NO2}$ reacts with water itself. As per [1] it is even better absorbed in water than in $\ce{NaOH}$. Ozone is soluble in water depending on the ...

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How is the water escaping?
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10 votes

There is a general belief that plastics are impermeable, probably because many liquids are stored in plastic containers. This is, however, not correct. Plastics are permeable to water and also to ...

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Separation of solvent from residue of material.
0 votes

Distillation is the way to go. Especially if you have to do it on industrial scale (if we have understood well, you have 2000 L to process). Normally it yields recovered solvent with low level of ...

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Redox potential of a lead–acid battery
3 votes

The potentials depend on the form of the compounds. It is true that in solution $\ce{Pb^{2+} (aq) + 2e^- -> Pb (s)} $ is -0.126 V. But in the case of a battery we have: $\ce{PbSO4 (s) + 2e^...

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etymology of supernatant
5 votes

It means "the liquid that swims above", from the Latin terms super = above and natare = to swim. So it is the liquid that remains on top. The subnatant would be the liquid at the bottom, in case you ...

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How much calcium hydroxide will precipitate after addition of sodium hydroxide into saturated calcium hydroxide solution?
Accepted answer
4 votes

A less analytic aproach: Initial concentrations: $K_{\mathrm{sp}}=\ce{[Ca^{2+}][OH^-]^2}=x\cdot (2x)^2=8\cdot10^{-6}$ $\ce{[Ca^{2+}]=0.0126}$ M; $\ce{[OH^-]=0.0252}$ M. Now 0.1 mol NaOH is added. ...

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How are poisons discovered? Does someone have to die/be poisoned from it first?
11 votes

Sometimes poisons are discovered by chance. At least that is what happened to me. We were researching on products made with malonodinitrile and enones. Since I was interested in the mechanism, I used ...

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Do acids react with neutral salts?
1 votes

Neutralization is a reaction between acid and base which results in the formation of a salt and water. When you have any ionic compound and dissolve it into water, dissociation occurs. This means that ...

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How is the cavity of a cyclodextrin chiral?
4 votes

It is because the constituent glucose molecules are chiral. In the image you can see that all the $\ce{CH2OH}$ groups in the center are out of the plane (towards you). These groups are on the upper ...

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Does deuterium exhibit hydrogen bonding?
1 votes

In short: Chemistry is about the last shell of electrons in the atoms. Nuclear differences are in the field of Physics. Deuterium is only a nuclear isotope of hydrogen, so no fundamental ...

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Best way to mix essential oils with water?
0 votes

To make an emulsion, a stable milky mixture of oil and water, you need an emulsifier. Alcohol is not an emulsifier, so the mixture will separate at some point. The most common emulsifiers used in ...

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Soxhlet extraction condenser - addition of compound to refluxing setup
2 votes

In my opinion the intention is to have a very slow addition of the reagent to the hydride. The compound is dissolved in ether, so a Soxhlet is of no use since it is for solids. What they are ...

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Is it a redox reaction if the oxidation state of the element has changed only in one of the products?
5 votes

One sulphuric acid is used to form sodium sulphate and the other one is used for oxidizing. So you have a reduction: $\ce{4H+ + SO4^2- +2e- -> SO2 + 2H2O}$ and an oxidation: $\ce{2Br- -> Br2 ...

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If melting points and freezing points are the same, what state is pure equilibrium?
4 votes

At the melting point there is a change of state. This means that solid is transformed in liquid or viceversa. For this process you need energy which is supplied or withdrawn in the form of heat. The ...

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Rate of reaction of silver salts of carboxylic acids having different alkyl groups towards Hunsdiecker Reaction
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6 votes

If the free radical is less stable, it will react faster. So once the system is started, the propagation (step 4) will proceed faster for primary radicals. That means that it is the limiting step ...

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HPLC method for salicylic acid
1 votes

Reverse phase is the standard in HPLC so, if you can use reverse phase do not complicate matters. Normal phase usually gives more problems than reverse phase and the stationary phases degrade faster. ...

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Oxidation of aluminum and manufacturing of electrolytic capacitors
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6 votes

You are performing an electrolysis. This means that on the (+) electrode de reaction is Al $\rightarrow$ Al$^{3+}$ and on the (-) electrode the reverse occurs. Distilled water is required to avoid ...

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Synthesis of Benzaldehyde and Aniline Schiff Bases
1 votes

The reaction needs acid catalysis but ethanol is fine as solvent. There will always be some starting materials left, but since the product is a solid and the reagents are liquid, the best (and ...

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Why do orthoesters react with Grignard reagents, but acetals and ketals don't?
Accepted answer
2 votes

Grignard reactions are performed in ether or THF. There you have only one -OR group on a carbon and, since it is the solvent, it is not reacting with it. This shows that not always a -OR group is ...

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How to dissolve PLA (polylactic acid)?
1 votes

When I started 3D printing I did some trials to dissolve PLA. I tried acetone, caustic and some other solvent. The only one that worked very well at room temperature was methylamine in water. ...

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