tschoppi
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How can antibonding orbitals be more antibonding than bonding orbitals are bonding?
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35 votes

Mathematical Explanation When examining the linear combination of atomic orbitals (LCAO) for the $\ce{H2+}$ molecular ion, we get two different energy levels, $E_+$ and $E_-$ depending on the ...

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Is alcohol really a solution?
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33 votes

Technically, alcohol is the name of a class of organic compounds containing one or several hydroxyl groups. Colloquially, the term "alcohol" is understood as you have described: A solution (of ...

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Proper typography of "NOx"
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32 votes

I quote the Green Book by IUPAC, 2nd printing (2008), section 1.6, enumeration item 2: The overall rule is that symbols representing physical quantities or variables are italic, but symbols ...

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How does Ostwald-Walker method work?
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17 votes

How are the vapors transported? The additional question from the comments: Why [is] the amt. of vapours taken up proportional to vapour press. Why directly proportional? Why not nothing else? ...

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Why is sand that insoluble?
14 votes

What is Sand? Scope of this Answer In order to give a good answer, we first have to decide on the type of sand we want to talk about, because its composition is highly dependent on that. Is it beach ...

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Is this sydnone aromatic?
13 votes

As correctly pointed out in the comments, the compound you present belongs to the class of sydnones. According to Hückel's rule, it should be aromatic, as the molecule is planar and contains $4n+2$ π-...

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Reaction intermediates of MnO2 catalyzed H2O2 decomposition reaction
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12 votes

Reaction conditions As Watts et al. have shown, the decomposition products of this Fenton-like reaction strongly depend on the $\mathrm{pH}$ of the solution.1 If performed in acidic conditions, the ...

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Difference between solubility and dissolution?
11 votes

Solvation [...] is the process of attraction and association of molecules of a solvent with molecules or ions of a solute. As ions dissolve in a solvent they spread out and become surrounded by ...

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Determine what the unknown element is
10 votes

The mass of the sulfate is $m_{\ce{SO4}} = 0.610~\mathrm{g}$, the mass of the metal is $m_\text{M} = 1.250~\mathrm{g}$. With the molar mass of the sulfate anion $M_{\ce{SO4}} = 96.061~\mathrm{g\, mol^...

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Can dust conduct electricity?
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10 votes

The answer to this question hinges on two key questions: What kind of dust are we dealing with? How is the dust arranged (i.e. what is your experimental setup)? Which Dust? Firstly, I'm going to ...

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Why do ionic compounds dissociate whereas coordinate complexes won't?
10 votes

First of all, who says coordination complexes don't dissociate? The interesting chemistry happens right there, and without dissociation no catalytic coordination compounds would be possible! Now, the ...

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Shouldn't the pH at the equivalence point always be 7?
9 votes

Two kinds of reactions have to be considered: Neutralisation of the weak acid with the strong base Secondary reactions from the products The neutralisation is fairly straightforward: $$\ce{HA + NaOH ...

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Are all PP(Polypropylene), i.e. resin code 5 plastics, safe for microwave and steaming?
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9 votes

No. Just because the polymer is of one or the other kind does not let you say what industrial process actually synthesized it. Subsequently it is impossible to know what trace chemicals are left in ...

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Why isn't organic chemistry taught in 3D?
8 votes

The problem it boils down to is ease of communication. When you develop a new synthetic pathway, or you find the newest cancer drug, you want to tell the whole scientific community about it, and the ...

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Best consumption-safe liquid for caffeine solubility?
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8 votes

Safety Warning Caffeine is a toxic substance. When following the advice below, always keep in mind the factors that will help you kill yourself if you are not careful! For more details you can ...

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Is there a relation between the ionization energy and the electron affinity?
8 votes

Okay, here's what I did (and I highly encourage everybody to do this along with this tutorial-style answer, just so you get the feel for prepping and looking at data from the world wild web). Data ...

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Why is the alpha particle called a particle when it is made of four particles?
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8 votes

Actually, the alpha particle contains two protons and two neutrons. It is what is emitted from the nucleus under alpha decay, giving off what was first classified as alpha radiation by Rutherford at ...

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Are ionic bonds stronger than covalent bonds?
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8 votes

In a fully covalent bond, you only have the mixing of the orbitals, as you said. But it's not only that, you also have coulomb interactions between the nuclei, that slightly raise the energy of the ...

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Is the proper formula for phosphorus oxide(V) P4O10 or P2O5?
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8 votes

The simplest types of chemical formulas are called empirical formulas, which use only letters and numbers indicating atomic proportional ratios (the numerical proportions of atoms of one type to those ...

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Find the initial volume of the weak acid given a titration graph
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7 votes

Outline There are three main points of interest in the titration graphic, and two you have found yourself. The three points are The start at $V_\text{titr}=0$ Halfway to the equivalence point at $V_\...

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Why is there an exponent 4 after the brackets in sp3?
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7 votes

The electron configuration of carbon is canonically written as 1s22s22p2. What you now can do is invoke orbital hybridization and combine the electrons in the 2s and 2p orbitals. Then you get sp3 ...

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How can I make an acidic pen to burn paper on writing on it?
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7 votes

You can pour anything into your pen. Is it a good idea? Most likely not. Is it dangerous? You bet! Is it a good idea to play with? NO! Whether it is legal or not to create such an object, you'll have ...

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Calculation of the specific rate constant (k)
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7 votes

We assume 1st order kinetics in hypochlorite and 1st order kinetics in the color. Putting this in the equation we get the following: $$\frac{\text{d}[\text{Red}]}{\text{d}t} = -k\, [\text{Red}]^1 \, [\...

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What is the (conceptual) difference between binding energy and adsorption energy?
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7 votes

For solids, the binding energy is what makes the crystal (if you will) hold together. It is what makes the individual constituents of the compound bind together. Adsorption however is an entirely ...

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If "Gas" belongs to "State of Matter" then what does "Metal" belong to?
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7 votes

"Metal" is a classification used by chemists and usually means something along the lines of "this electrically conductive, usually solid element that is deformable". The other way around: Chemists ...

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Where do the electrons that are released in the sun go?
7 votes

Some of the electrons will react with positrons formed during the fusion processes; they annihilate each other and give off high-energy radiation (also called gamma rays): Source But this process ...

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Why is proton coupling through bonds and how does this affect identical protons?
6 votes

How does a proton create a magnetic field that influences the neighboring protons (mainly) trough bonding and not trough space? A proton doesn't interact with another proton by producing a magnetic ...

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How do I figure out the relative polarity of organic compounds?
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6 votes

General steps to figure out the polarity (or at least relative polarity) and subsequently the relative boiling point of compounds: Acquire the correct geometry Estimate dipole moments Sum up ...

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How to determine the iron content in spinach with a spectrometer?
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6 votes

Here's how I approached the problem. Plot the Data Below is the plot I quickly hacked together, and a fit of the form $g(x) = a\cdot x$. (Note that I do want the line to go through (0,0) because the ...

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How can the number of molecules and atoms be the same in a gas?
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6 votes

The gas was one (or a mixture) of the noble gases, as every other gas is composed of more atoms than molecules. Example Helium: $1~\text{mol}~\ce{He}~\text{gas} = 1~\text{mol}~\ce{He}~\text{atoms}$ ...

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