Questions tagged [intermolecular-forces]
The forces, either attractive or repulsive, that exist between molecules due to electric charges or varying electron cloud distribution. This tag could also include intra-molecular attractions (within one molecule itself) often found in a protein amino acid residues.
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Dipole vs Dispersion Forces
Sometimes dispersion forces can outweigh dipole interactions given that it is sufficiently large. Some large enough nonpolar molecules have a higher boiling point than small polar molecules. At what ...
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Cucurbiturils and cyclodextrins — what is the difference?
One was reading about the cyclodextrins on this site and decided to further investigation on the matter. One encountered a class of molecules called cucurbiturils, which are macrocyclic molecules that ...
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Why does AsH3 have a higher boiling point than HBr?
Aside from the general trend of the boiling points of the hydrides, I noticed how the group 15 hydrides somehow "overtook" the group 17 ones in boiling point, which felt weird.
Notably, H-...
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Does glucose form a molecular lattice in the solid state?
When I look at solid iodine, it is a molecular lattice held by van der Waals forces. Glucose is also simple molecular and so I naturally assumed that because it is solid like iodine, it forms ...
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When does a long carbon chain become more significant to the boiling point of a substance than polarity? [closed]
I'm asked to sort the following compounds according to their boiling point (in an increasing manner): acetic acid, sodium chloride, and pentadecane (C15H32). Obviously, sodium chloride will have ...
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Why do we not consider the force of repulsion between two cations/anions in an ionic lattice?
Obviously, there are forces of attraction between the Cl- anions and the Na+ cations. But aren't there also forces of repulsion between the Na+ atoms (look diagonally between the grey atoms)? Likewise ...
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Are van der Waals forces the same thing as intermolecular forces? [duplicate]
Like the name suggests, intermolecular forces are those between molecules and can be forces of attraction between permanent dipoles or temporary dipoles. However, it seems that the definition of van ...
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Why is the Van der Waals constant of water lesser than benzene?
Van Der Waals constant of water and benzene ($a$) are $5.537$ and $18.82$ respectively.
I have read that the value of Van Der Waals constant indicates the extent of attractive forces.
By this, ...
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Cyclodextrins: Is there really a hydrophobic interior and hydrophilic exterior?
I do not get most of the explanations on why cyclodextrins are so good at hosting hydrophobic molecules. It is true that the hydroxyl groups are pointed outwards and thus the cavity is definitely less ...
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Is Hydrogen Bonding a Type of Dipole Dipole Interaction?
I understand that dipole dipole forces is due to the attraction of the different partials charges of atoms in different molecules due to their different electro-negativities.
For hydrogen bonding, ...
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What explains the relative order of melting and boiling of oxygen and nitrogen?
Why is the melting point of nitrogen ($\ce{N2}$) greater than that of oxygen ($\ce{O2}$)? After all, both are non-polar, and $\ce{O2}$ has more electrons than $\ce{N2}$.
In addition, why is the ...
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London forces and van der Waals interactions
London or dispersion forces are considered to be type of van der Waals (vdW) interactions or inter-molecular forces that are neither ionic or covalent. However, is there way to distinguish dispersion ...
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Complexities in Long-Term Storage Container-Planning for DIY Ferrofluid Experiment
I’m a big 2-part resin crafter, so my question pertains specifically to the interactions between ferrofluid and resin.
I recently acquired a large glass tube with open ends and I’m trying to figure ...
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Why do alkanes have higher boiling point than their ether counterparts?
Based on my understanding of intermolecular forces, I expect dipole-dipole interactions to be significantly stronger than van der Waals' interactions. Hence, I expect ethers (which obviously have ...
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Melting Point Order of Benzene Derivatives
Q)Compare the melting points of the following?
o-Hydroxybenzaldehyde
o-Methoxybenzaldehyde
p-Hydroxybenzaldehyde
p-Methoxybenzaldehyde
My attempt: Intermolecular H-bonding increases melting point ...
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Are London dispersion forces in xenon tetrafluoride strong enough to make it a solid?
Xenon_tetrafluoride ($\ce{XeF4}$) is a well-known square-planar molecule with no dipole moment. Molecules are thus have to be bound to each other by London dispersion forces (LDF) which are known to ...
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Why does CO2 have higher boiling point than CO?
The intermolecular forces between $\ce{CO2}$ molecules are dispersion forces, while the forces between $\ce{CO}$ molecules are mostly dipole-dipole attraction forces. So, why does $\ce{CO2}$ have a ...
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A curly arrow can only have its tail starting from a double bond or lone pair?
According to this video, a curly arrow representing a reaction mechanism can only have its tail starting from a double bond or a lone pair.
I am wondering if the tail of a curly arrow could also start ...
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Why do stronger intermolecular forces lead to a larger change in temperature?
We performed an experiment where tissue paper soaked in various chemicals was wrapped around the end of a temperature probe.
The chemicals with stronger intermolecular forces had a smaller drop in ...
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Why is the boiling point of heavy water higher than normal water?
In class, we learned that London forces become stronger as relative molecular mass increases. Not just in organic chemistry but in things like the halogens.
However, as I understand, the London forces ...
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Why is hydrogen bonding stronger than dipole-dipole interaction of carbonyls? [duplicate]
My understanding was that hydrogen bonding is much stronger than other dipole-dipole interactions since the dipole between hydrogen and O/F/N is much greater than other dipoles. However, the dipole ...
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How would you explain the general trend in melting point between Group 1 and Group 2 chlorides?
This question is based off of the attached chart. I notice how there's a general increase in melting point down group 2 chlorides and a general decrease (except for Lithium) down the group 1 chlorides....
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Is a microplastic saturated ferrofluid polar or nonpolar? [closed]
In my experiment (Junior science fair) I submerged a magnetic chip collector holding my ferrofluid (magnetite and grape seed oil) with polypropylene beads (attracted as part of the experiment) into ...
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How do pencil erasers erase on a fundamental level? [duplicate]
One could say we're taking advantage of friction, but I want to dig deeper down to molecular/atomic level: what's the process or chain that happens when one erases from a macroscopic to a more ...
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Potential Energy Function for Two Atoms
The potential energy between two atoms, in a molecule, is given by
$$U(x)=\frac{a}{x^{12}} -\frac{b}{x^6}$$ where $a$ and $b$ are positive
constants and $x$ is the distance between the atoms. The atom ...
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Why does fluorine form only one hydrogen bond, but oxygen forms two?
Oxygen forms two hydrogen bonds as it has two lone pairs. So, why does fluorine only forms one hydrogen bond having three lone pairs?
Both oxygen and fluorine have nearly the same size, so steric ...
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Reason for vibration of molecules
Why do molecules of a body exhibit vibrational motion? Is it due to interaction between various molecules of the body, or interatomic interactions between atoms in the same molecule? If it is because ...
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Why doesn't the viscosity of water change much with temperature like it does for other substances?
I would like to know why water doesn't ever become like syrup before it freezes when many other liquids, such as hydrocarbons, seem to have a more gradual change from becoming more viscous and then ...
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How to calculate the ground state molecular potential curve of Lithium in different spin configuration?
I am a physics student and interested in Atom, and molecule optical physics. I am studying Feshbach resonance and I need to know the potential curve of the molecule, then I ask question in physics ...
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Can Steel be Created from Germanium?
I've tried searching with Google as well as on this website, but I haven't been able to find even a question asking about it. It was something that I was just curious about, but my limited knowledge ...
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Why is the pressure correction in the van der Waals equation proportional to (n/V)^2?
The van der Waals equation for real gases is stated as follows:
$$\left(P + \frac{an^2}{V^2}\right)(V - nb) = nRT$$
For the coefficient $b$, we can reason out that more the number of molecules, the ...
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Why is octane more volatile than water while having a higher boiling point?
Octane has a boiling point of 120 °C. Water has a boiling point of 100 °C. The definition of boiling point is, "the temperature which the liquid substance's saturated vapor pressure equals the ...
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why Tin/Zinc alloys can be used to solder aluminum and Tin alone does not "wet" the aluminum?
It is impossible to solder aluminum with only tin, tin does not "wet" aluminum surface because of the instantaneous reaction aluminum/oxygen on the surface of the base metal (aluminum). I ...
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Why so many intermolecular forces?
I was recently learning about intramolecular and intermolecular forces. It seems there are a variety of interactions ( Dipole-Dipole. Ion-Dipole etc ). Why must this be the case? Couldn't all chemical ...
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What is the effect of dissolving ammonia in water on hydrogen bonding?
Hydrogen bonding exists between $\ce{NH3}$ molecules. When $\ce{NH3}$ is dissolved in water, I know that hydrogen bonds are formed between $\ce{NH3}$ and $\ce{H2O}$ molecules. However, do the $\ce{NH3}...
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Why surface tension acts tangentially if there is a net inward force? [closed]
I understand that surface tension is caused by an imbalance of forces for molecules on the surface in comparison to those that lie within. As a result, this creates a net inward force that seeks to ...
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Why does N,N-dimethylethanamide have a higher boiling point than butanoic acid?
According to Wikipedia, N,N-dimethylethanamide has a boiling point of $\pu{165.1 °C},$ while butanoic acid has a boiling point of $\pu{163.75 °C}.$
From what I learned, butanoic acid should have a ...
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Why don't molecules of ionic compounds exist?
My book says:
As single ions of a metal are not associated in the solid with single ions of a non metal, separate units of ionic compounds do not exist. It is, therefore, wrong to talk of a ...
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Pressure vs volume plot for real gas and ideal gas
Background
Recently I have been studying about the states of matter and came to the topic of ideal gases and real gases, and the laws related to them. While studying it from my textbook, I saw the ...
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Why does Methanol have a higher surface tension than Ethanol? [closed]
I am researching the surface tension of different alcohols and found something odd: the surface tension of Methanol was higher than that of Ethanol, which doesn't make sense to me. My understanding is ...
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Is there experimental evidence to show boiling point increases with external electric field, and if so, by how much?
I was wondering whether anyone has demonstrated that a liquid will have a higher boiling point if it is placed in a very large electric field. I believe to be the case, since induced dipoles would be ...
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Trying to understand the causes and implications of kinks in fatty acid chains
I watched this video (The Deal with Fat by SciShow):
https://www.youtube.com/watch?v=mvvx2yQRbzQ
To summarize the main points I want to discuss:
Saturated fats are chains without any double-bonds ...
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Intermolecular Forces for Ionic Compound?
So in class we have learned London dispersion, dipole-dipole, ion-dipole and hydrogen bonding for intermolecular forces. Our teacher always uses covalent molecules as examples. So I was wondering ...
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Air/Acetonitrile Interfaces
Say I drop some acetonitrile on a grounded surface and it forms a meniscus. The acetonitrile is in air. Lets forget about evaporation for the moment.
Will there be an interfacial dipole formed by the ...
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Is it possible to have an anhydrous solvent for virology, specifically in vitro phage assembly?
Typical protocols for lambda phage in vitro assembly call for you to dump all your viral components and buffer solutions into water. Water is a great solvent, drives extraction of energy from atp, and ...
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Why aren't the Anton computers used more widely?
The Anton computers are purpose-built by DE Shaw research for molecular dynamics simulations. They achieve performance up to an order of magnitude faster than can be achieved with commodity hardware, ...
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Why is the van der Waals constant b of NH3 less than that of N2?
According to the actual data, van der Waals constant $b$ of $\ce{NH3}$ gas is $\pu{0.0371 L mol-1}$ and that of of $\ce{N2}$ gas is $\pu{0.0387 L mol-1}$.
But it should be,
$$b_{\ce{NH3}}>b_{\ce{...
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Hydrogen bond in water vapor [closed]
As the temperature increases and liquid water changes to gas, are ALL the hydrogen bonds broken or they are just weaker?
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Why do some hydrates need to be heated over 100 Celsius to evaporate the water?
If the boiling point of water is at 100 °C, why does a hydrate need to be heated higher than that to evaporate water from the crystals? Does it have anything to do with their intermolecular forces?
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Relation between molar mass and van der Waals force
In the book that I'm reading, it is mentioned that higher molar mass results in stronger van der Waals force but didn't continue why.
I wonder why is that so? Molar mass actually depends on the number ...
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