30
votes
Why is the boiling point of fluorine lower than that of oxygen?
It would be tempting to argue that fluorine is so electronegative and holds its electrons so tightly that their polarizability is reduced, thus so are the dispersion forces in $\ce{F2}$. But upon ...
- 38.2k
27
votes
Accepted
Dipole moment of cis-2-butene
Mini Research Project Time
Updates
Added CCSD(T) $n_i$ and dipole moments and tweaked discussion (the delay was caused by a system-wide storage upgrade on the machines which took nearly a week to ...
- 4,549
20
votes
Accepted
Why is water "the universal" solvent?
To directly address where the phrase comes from:
Water is called the "universal solvent" because it dissolves more substances than any other liquid. -USGS
What are ideal qualities of solvent?
The ...
- 4,395
20
votes
Why is water "the universal" solvent?
TL;DR: Water is incredibly easy to get and work with.
In full
Water is a good solvent for polar compounds[citation needed], and the reasons for this are laid out pretty well by John Snow, but that's ...
- 1,260
18
votes
Accepted
Quadrupole moment of a molecule
What is a quadrupole moment of a molecule and how does it arise?
This explanation is geared at someone with one year of chemistry. It captures the gist but is not rigorous:
To test for monopoles, ...
- 30k
17
votes
Accepted
Why is carbon dioxide nonpolar?
so wouldn't it be that you
would have an even more positive carbon and 2 partially negative
oxygens
Yes, your analysis is correct to this point. A chemist would say that the bonds in $\ce{CO2}$ ...
- 81.6k
16
votes
Why is water "the universal" solvent?
Just to provide an alternative answer:
Consider a solvent miscibility table like the one linked.
What is the least miscibile solvent? Water! Water is the worst solvent. Water is immiscible with 17 ...
- 38.8k
15
votes
Accepted
Why don't polar and non-polar compounds dissolve each other?
Very simply, you explain the reason for this solubility rule by taking in consideration the energy requirements for the breaking of intermolecular forces between the molecules in the solute and the ...
- 7,046
14
votes
Accepted
Why is tetrafluoromethane non-polar and fluoroform polar?
Draw the structures in 3D and then you will see why one is polar and the other not.
$\ce{CF4}$:
As you can see this molecules adopts a tetrahedral geometry which is perfectly symmetrical in every ...
- 14.9k
14
votes
Accepted
Is the triiodide ion polar?
The structure of the triiodide ion places a negative formal charge on the central iodine atom.
No it doesn’t. The two resonance structures that describe the four-electron three-centre bond put the ...
- 63.6k
14
votes
Accepted
Why are dipoles "permanent/induced dipole permanent/induced dipole" and not just "permanent/induced dipole" once?
Because it takes two to tango.
Dipoles interact with each other. A Lone dipole has nothing to interact with (other than an electric field, but if we ignore some externally applied macro field, there ...
- 32k
13
votes
Non-zero dipole moment of hydroquinone
According to J. Am. Chem. Soc. 1945, 67 (2), 322–324:
Planar configurations for resorcinol and hydroquinone are more acceptable on comparison of experiment and calculation than are the structures ...
- 7,892
12
votes
Dipole moment of cis-2-butene
This was actually an interesting problem.
Well, I ran a quick calculation using Avogadro and GAMESS, although other packages would work. This is a CCSD/aug-cc-pVTZ calculation, pretty much the gold ...
- 26.8k
12
votes
Is the triiodide ion polar?
I would argue it is a polar molecular ion.‡ In the comments to this question there has been already pointed out that the term "polarity" is quite ill-defined.
Many chemists understand that if a ...
- 42.2k
11
votes
Accepted
Difference of dipole moments of dichloromethane and trichloromethane?
Just to add some quantification to Ben Norris's answer. Consider each $\ce{C-Cl}$ bond, which has a bond dipole moment of magnitude $A$. The contribution from $\ce{C-H}$ is neglected here to simplify ...
- 6,364
11
votes
Accepted
If CO2 is nonpolar how come much more dissolves in water than O2?
Taken from my answer to your original question
There are a couple of reasons why $\ce{CO2}$ is more soluble in water than $\ce{O2}$. Because the two $\ce{C=O}$ bonds in $\ce{CO2}$ are polarized (...
- 81.6k
11
votes
Why is carbon dioxide nonpolar?
In understanding molecular polarity you need to take the whole structure into account.
Your reasoning is correct as far as the parts of the molecule are concerned. The individual bonds are polar.
...
- 32k
11
votes
Is the triiodide ion polar?
If you accept the Atkins Physical Chemistry definition of polar:
A polar molecule has a permanent electric dipole moment arising from the partial charges on its atoms
Then the answer turns upon ...
- 38.8k
11
votes
What is the exact reason that compounds such as carbon dioxide cannot interact with other compounds through dipole-dipole interactions?
As the other answers have indicated, CO2 has no NET dipole moment. However it does have two dipoles pointed in opposite directions (as OP keeps mentioning). This means that CO2 can possibly interact ...
- 459
10
votes
Why is water "the universal" solvent?
It's worth noting some of the history behind the term "universal solvent," and why it is used even though water isn't truly universal or even necessarily the most versatile solvent available.
Before ...
- 347
10
votes
Accepted
What is the explanation of the changes in stability going down a group for carbonates, bicarbonates, fluorides, and chlorides?
Carbonates
The quote from your text:
Carbonates of alkaline earth
metals are insoluble in water and can be
precipitated by addition of a sodium or
ammonium carbonate solution to a solution
...
- 4,395
10
votes
Why don't polar and non-polar compounds dissolve each other?
TL;DR
It's because the enthalpy changes of a solution generally don't favor dissolution.
A longer version:
To explain this, usually the enthalpy change explanation is given. For the sake of ...
- 10.1k
10
votes
If the polarity of the solvent increases, will the Rf value increase or decrease?
I wish we would stop teaching chromatography in terms of "polar" and "nonpolar."
The aspirin will interact fairly strongly with the silica due to hydrogen bonding/electrostatic interactions of the ...
- 3,185
9
votes
Why is carbon dioxide nonpolar?
The formula for the net dipole moment $\vec{\mu_{net}}$ of an overall neutral system of $n$ charged point particles is given by:
$$
\vec{\mu_{net}} = \sum\limits_{i}^{n} q_i\vec{r_i}
$$
where $q_i$ ...
- 11.6k
9
votes
What is the exact reason that compounds such as carbon dioxide cannot interact with other compounds through dipole-dipole interactions?
Carbon dioxide is more than linear. It's symmetric, and the axis of symmetry perpendicular to the bonds also applies to whatever dipole moment it has. The only vector that looks the same after being ...
- 16.7k
9
votes
Easiest way (software) to visualize charge density from an .xyz file with point-charges?
After the successful calulation of the electrostatic surface potential, molden equally allows the display of it in a form like
(source)
A step-by-step, hopefully still functional, tutorial is this. ...
- 23.6k
9
votes
Halogenation of Phenol
The reaction of phenol with bromine is known as bromination of phenol. Solvent has great influence on the reaction. In different solvents, different products are obtained. The action of bromine on ...
- 312
8
votes
Difference of dipole moments of dichloromethane and trichloromethane?
Since you know about vectors, then the piece you are missing is probably the proper three-dimensional structure of the molecules.
Trichloromethane (chloroform)
Notice that the third chlorine atom ...
- 41.3k
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