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Questions tagged [intermolecular-forces]

The forces, either attractive or repulsive, that exist between molecules due to electric charges or varying electron cloud distribution.

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Why does graphite have a high melting point even though its intermolecular forces are weak?

From what I've read online, when a substance undergoes a state change, the intermolecular forces are broken. The covalent bonds are not broken (http://www.bbc.co.uk/schools/gcsebitesize/science/...
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What is the maximum distance over which van der Waals forces act?

The VDW radius places a lower limit on the distance between atoms mutually attracted to one another. I am looking for the upper limit: what is the name of the concept or theory that describes the ...
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Does gas chromatography follow the “like interacts with like” rule of thumb?

The "like interacts with like" rule of thumb works well when there are polar and non-polar molecules that are mobile (liquid-liquid extraction, membrane vs cytosol, questions of solubility). Polar ...
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Intermolecular forces ICl [closed]

Why does the ICl molecula have permanente dipole-permanent dipole interactions ad also an induced dipole-induced dipole?
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2answers
44 views

What would be the intermolecular forces between the molecules of methanetetrol?

Methanetetrol has the following chemical formula: $\ce{CO4H4}$. It is also referred to as orthocarbonic acid. Since the molecule has a molecular geometry of a tetrahedron, similar to that of a ...
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1answer
35 views

Why is boron or carbon solids and chlorine a gas at room temperature

I know different compounds have different states at room temperature because of inter-molecular forces ( dipole-dipole force, hydrogen bonding, and London dispersion forces). But how do they act on ...
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2answers
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Do molecules with polar bond, but with no dipole moment experiences a greater effect from the london dispersion forces?

Do molecules that have polar bonds and a structure that makes the polarity of those bonds cancel each other out, experience a greater effect from the London dispersion force, than molecules with a ...
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Non-covalent interactions

According to Keesom, Debye and London effect, the non-covalent reactions should be stronger, the bigger are electric charge differences between two interacting particles. E.g. Ion-induced dipole are ...
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What type of interactions occur when CH4 dissolves in CCl4 [duplicate]

When ionic compounds dissolve in polar solvents many types of factors come into play determining their solubility. Some of them may be: ion- dipole interactions, lattice energy, high dielectric ...
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Why do higher intermolecular forces lead to a higher change in temperature?

We performed an experiment in chemistry where tissue paper soaked in various chemicals was wrapped around the end of a temperature probe. The chemicals with stronger intermolecular forces had a lower ...
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2answers
52 views

Why does atomic charge not balance in nuclear reactions?

In the discovery of neutron, the bombardment of beryllium with alpha particles is well known. $$\ce{^9_4Be + ^4_2He^2+ -> ^12_6C + ^0_1n}$$ I don't understand how the electrons add up. As alpha ...
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1answer
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Understanding water models?

I generally work on fluid flow, so some basic concepts in chemistry are new to me. Work I'm doing requires use of molecular dynamics (MD) to do classical potential simulations of water–NaCl systems ...
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How can I define a torsion force field for $n$ points in space?

I would like to define a model for torsion force field between $n$ point in space. I thought to generalize the OPLS model: $$ \sum_\mathrm{dihedrals} \left( \frac {V_1} {2} \left [ 1 + \cos (\phi-\...
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262 views

Boiling points and melting points of nitrogen and oxygen

Why does nitrogen have a higher melting point, but a lower boiling point than oxygen? I have been taught that nitrogen has a higher melting point as it has a larger molecular size, but doesn't ...
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How does Coulomb's Law explain the strength of the dipole-dipole force?

How does Coulomb's Law explain the strength of the dipole-dipole force? Using Coulomb's Law, predict whether HCl or HBr has stronger dipole-dipole force. I know that HCl has stronger dipole-dipole ...
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1answer
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Calculate force on atoms given the energy of configuration, trajectory of simulation and position of atoms in each frame

Background I am using a neural network to calculate the potential energy of atoms in a configuration and then adding energy of all atoms to compare it with the true energy of the configuration(label) ...
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3answers
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If all intermolecular forces are electrostatic in nature, why don’t large non polar molecule dissolve in water?

If I have a large non-polar substance A that forms strong dipole-induced dipole force (DIDF) with water, with strength comparable to that of H-bonds between water molecules, will A dissolve in water?
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1answer
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Relative magnitudes of intermolecular forces from phase diagrams

Is it possible to say whether or not a system A or B has stronger intermolecular forces from a phase diagram according to which: The $T_{\text{b}}$ of A is lower than the $T_{\text{b}}$ of B. The $T_{...
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1answer
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Intermolecular interaction between aniline and dichloromethane

Short background As it is known there are interactions between: Charges Charge and dipole Hydrogen bonding van der Waals (VDW) forces From stronger (1) to weaker (4). VDW forces are divided into ...
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1answer
48 views

Relating properties and structures of polymers

Why would it be more favorable for a polymer designer to design copolymers with irregular chain structures, rather than design homopolymers? Hint: Discuss intermolecular bonds I understand that ...
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1answer
85 views

What are the intermolecular forces between polychloroethylene?

Does polychloroethylene have only van der Waals/London forces between its molecules? Surely, if all the chlorine atoms are on one side, due to the fact that chlorine is more electronegative than ...
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1answer
47 views

Help with Carbon Fibre

I'm having trouble finding articles about carbon fibre that don't contradict other articles. I just have a few questions about the atomic structure and the intermolecular and intramolecular forces. ...
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1answer
53 views

Is the electrical conductivity only measurable in aqueous solutions? [closed]

I have been looking for other ways to measure it, but all I've found is through aqueous solutions. So I want to know if there's another way to do it, or why it isn't possible through other means.
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Why don't all atoms stick together due to dispersion forces if these forces are ubiquitous? [duplicate]

If dispersion forces are always there wherever there are electrons, why don't two pieces of copper for instance meld together when put next to each other? Or why don't other substances stick to each ...
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1answer
669 views

Why does Xe have a higher boiling point than Ne? [duplicate]

I am certain that the reason involves intermolecular forces, but since both $Xe$ and $Ne$ are noble and non-polar gases, shouldn't these forces have a much smaller effect or negligible on boiling ...
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Why do intramolecular forces weaken due to heat?

In my most recent research into thermoplastics, I was unable to find any information regarding what actually happens to intramolecular forces when heat is applied.
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Experimental bond lengths and binding energies of diatomic molecules

Is it possible to find the experimental values of the bond length and the binding energy of the diatomic molecules $\text H_2$, $\text{Be}_2$, and $\text{Ar}_2$ in one source? I found a lot of ...
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1answer
107 views

Will ice be cold or not when formed using pressure? [closed]

We know that ice can be formed either by lowering the temperature of water or by applying more pressure. If we lower the temperature of water the ice so formed will be cool which is obvious. If ice ...
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2answers
57 views

What makes a diatomic bond strong? [closed]

What are the factors affecting the strength of bonds? Ex:- why, we need less amount of energy to break Br-Br bond than Cl-Cl bond?
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1answer
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electronegativity and hydrogen bonding [duplicate]

I have a basic idea why, but can someone just confirm, why chlorine isn't able to hydrogen bond despite the fact that it has the same electronegativity value as nitrogen.
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0answers
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How to know if a sample suffered descomposition during melting point? [closed]

If I take a sample in order to determine its melting point, how do I know if that sample suffered a descomposition?
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0answers
48 views

What is “time-dependent evolution of the complex noncovalent interaction networks” and why this is important?

From Maximilian Scheurer, Peter Rodenkirch, Marc Siggel, Rafael C. Bernardi, Klaus Schulten, Emad Tajkhorshid and Till Rudack Biophysical Journal, Volume 114, Issue 3, 577-583: One of the most ...
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1answer
244 views

London Dispersion Forces and Dipole-Dipole forces together? [closed]

How do London Dispersion Forces and Dipole-Dipole forces exist at the same time between polar molecules?
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Mechanism behind colloidal suspension

There are two most common ways to stabilize colloids -- electrostatic stabilization and steric (or polymer mediated) stabilization. To my understanding, most of the electrically stabilized ...
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1answer
66 views

Van der Waals interaction and magnetic dipole dipole interaction

I have a conceptual question that bothers me. From what I understand, van der Waals forces are the primary source of inter-molecular interaction. There are three different possible origins for van ...
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2answers
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Why do alkanes have higher boiling point than their ether counterparts?

Based on my understanding of inter-molecular forces, I expect dipole-dipole interactions to be significantly stronger than van der Waal's interactions. Hence, I expect ethers (which obviously have ...
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1answer
131 views

Surprising values of intermolecular forces of ethane, oxygen and xenon

I know that gases with stronger intermolecular forces should have a larger value of the van der Waals constant $a$. So I looked up a table on van der Waals constants and tried to reason about the ...
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Why is this scintillator component turning into a milky-white emulsion?

I am a chemistry and physics double major doing some chemistry work in a nuclear physics lab. My mentor is a physicist, so his area of expertise is occasionally mismatched with what I need for my ...
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1answer
58 views

Are intermolecular forces a type of chemical bond?

My chemistry teacher told me that chemical bonds are of two types: intramolecular and intermolecular. He said that intermolecular forces come under the category of intermolecular chemical bond. I ...
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1answer
1k views

Why does acetone have a lower boiling point than hexane?

Why does acetone have a lower boiling point than hexane? I thought that since hexane is non-polar then it should have weaker intermolecular forces and a lower boiling point, but it doesn't. Why? For ...
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1answer
671 views

Why is the boiling point of polonium less than that of tellurium?

My textbook states that polonium has a lower boiling point than tellurium because it has weaker intermolecular forces of attractions (van der Waals forces). Why are van der Waals forces of attraction ...
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1answer
404 views

How to identify hydrogen bonds and other non-covalent interactions from structure considerations?

Chemistry is governed by a wide range of interactions, from ionic and covalent bonding, or other types of strong interactions, towards weaker types of bonding, attraction, or repulsion, that typically ...
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1answer
372 views

For two compounds that are symmetrical, why does the more compact one have a higher melting point?

In this post, I refer to two molecules B (Di-tert-butyl ether) and C (Dibutyl ether). Wikipedia: Di-tert-butyl ether (B) b.p. 107.2 C m.p. - 61 C ...
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1answer
581 views

Why is the boiling point of hydrogen sulfide higher than that of hydrogen chloride?

The boiling point of $\ce{H_2S}$ is higher than $\ce{HCl}$. Is this due to the greater number of hydrogen bond that $\ce{H_2S}$ can form compared to $\ce{HCl}$? I found this explanation for the ...
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2answers
548 views

If we start heating a substance, does it melt when we break its intermolecular bonds? [closed]

I was reading the 2 following posts: Do substances melt when we break their intermolecular bonds? Is melting/boiling point of ionically bonded substance higher than of covalently bound? Altough ...
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0answers
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Chemical bonding [duplicate]

How do we compare the strength of permanent dipole permanent dipole (PDPD) interaction? Is it by bond polarity? Since H-X (where X is halogen) is polar, and for bond polarity (PDPD bond strength): ...
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1answer
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Why is the melting point of PCl3 less than that of PCl5?

From just the IB chemistry bonding chapter information, you would normally deduce that $\ce{PCl3}$ and $\ce{PCl5}$ are both covalent molecules. However, as $\ce{PCl3}$ has a dipole moment, it has ...
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2answers
172 views

Reversed size dependence in ion solubility

My book says that solubility increases with interionic distance, because the attractive forces between ions gets smaller. However, if one of the ions in a binary ionic system is very large compared to ...
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2answers
516 views

Forces of attraction of hydrated potassium ion in aqueous solution

I want to study the intermolecular forces (IMFs) in hydrated potassium ion, $\ce{K+ (aq)}$ in an aqueous solution of $\ce{KCl}$. According to my thoughts, among the 4 IMFs I know: London dispersion ...
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0answers
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How can copper(II) sulfate crystallize outside a glass vial?

I'm making copper sulfate crystals in glasses. Within a few weeks, the copper sulfate seems to crystallize both inside and outside the glass: (A few weeks after making a new solution) (Yet another ...