Questions tagged [molecules]

An electrically neutral entity consisting of more than one atom (n > 1). Rigorously, a molecule, in which n > 1 must correspond to a depression on the potential energy surface that is deep enough to confine at least one vibrational state. This tag should be applied to question about certain molecules or a class of them.

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1answer
48 views

Identifying molecule with three adjacent six-membered rings from blurry image

I have found this isolated image on one of my old hard drives and I would like to know what molecule does the image represent:
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What is the use of both mol and mass representing the same thing i.e. amount of something? [closed]

A mol is a unit but also has a magnitude. How can a unit have a magnitude? And if mole is used to measure an amount of substance than what does mass measure?
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If cigarette smoke is exhaled, what happens to the accompanying exhaled breath?

I want to know what happens to that breath. To help you answer this question, consider in your mind these subquestions: Is there a necessary principle at work, by which you know that it vanishes/...
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Kinetic Diameter: How to calculate it? Pressure influence?

Wikipedia states: Kinetic diameter is a measure applied to atoms and molecules that expresses the likelihood that a molecule in a gas will collide with another molecule. It is an indication of the ...
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23 views

Database for experimental diatomic ionization energies

I am looking for a database, in which the experimental ionization energies (and e.g. heat of formation) of atoms and diatomic molecules are listed as files. If it comes with a Python package, that ...
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1answer
62 views

Can atomicity be infinity? [closed]

My chemistry teacher told us that graphite or diamond had an atomicity of infinity. However, the definition of molecule in my testbook is A molecule is the smallest part of an element or compound ...
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1answer
76 views

Software that determines whether a molecule can exist and draw it from a formula?

I have run calculations that predict atomic configurations. As a simple example, in a system that contains H and O, I might get a list like: ...
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66 views

Molecular formula with CH without numbers [closed]

I was wondering if there exists a compound, the molecular formula for which includes CH but does not include any numbers. Like ...
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30 views

How one can calculate Si-O-Ca/Mg valence angle energy?

I want to perform the relaxed scan (or relaxed surface scan) for the valence angle energy of Si–O–Ca, Si–O–Mg, Al–O–Ca, and Al–O–Mg. I will use DFT (ORCA), probably B3LYP and triple zeta basis set (...
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What is kekulization (in RDKit)?

It's been a while since I've studied chemistry. Now, I am reading the documentation of RDKit. At a certain point, the term "kekulization" is mentioned. What is kekulization (in RDKit, if this is not a ...
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1answer
105 views

What is a molecule’s smallest set of smallest rings?

It is been a while since I've studied chemistry. Now, I am reading the documentation of RDKit, where they mention the expression "smallest set of smallest rings" (SSSRs). I understand that a ring is a ...
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56 views

Is water the most common multielemental compound?

Water is a very common substance, not just on Earth, but also in space. Although water usually occurs in space as a solid and occasionally as a gas and relatively rarely as a liquid, the most common ...
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When we tear a piece of paper do some of the molecules fall of as we tear? [duplicate]

So I mean are some of the molecules lost(fall of) while we tear the paper? Or all the molecules present in the sheet of paper just get divided in the two new pieces created?
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What is molecular potency?

In the paper Junction Tree Variational Autoencoder for Molecular Graph Generation, the authors propose a ML model that is based on the message passing neural network, variational auto-encoder, the ...
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2answers
59 views

Is the molar mass of a molecules lowered by the binding energy of the chemical bonds?

When calculating the molar mass, is there any measurable difference in total mass of the molecule due to the loss of binding energy?
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1answer
109 views

What do we learn from an isotope peak (or M+2 peak) in a mass spectrum?

Mass spectrum of a molecule showed molecular ion peak and its isotopic peak in 1:1 ratio. What is the possibility of the atom present in the molecule? Since it is mentioned that it has a ...
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Predict the number and nature of bonds using Molecular Orbital Theory

I found the following question in a high school chemistry problem book: According to Molecular Orbital Theory which of the following is true: (A) In $C_2$ molecule both the bonds are $\pi$ ...
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2answers
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How to determine the boiling point of substances? [closed]

Which of the substances has the lowest boiling point? a) $\ce{H2O}$ b) $\ce{H2S}$ c) $\ce{H2Se}$ d) $\ce{H2Te}$ I've been searching for any formula or rule to determine this, but I read that it ...
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Molecular weight of NiMnGaFe compund problem

I have a big problems calculating molar/molecular etc masses, because in my case I have a monocrystal, co I cannot imagine it as a molecule and my compound is made of Ni-Mn-Ga-Fe. I know the mass and ...
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1answer
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Why can you blow bubbles in milk but not hot cocoa, which is milk based?

My daughter is asking this question and I’m assuming it’s something related to the cocoa added to milk but don’t know what change is happening molecularly and why it would affect the bubbles. Thanks! ...
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Is the existence of chirality center equivalent to chiral?

To make my question more clear, I want to ask two questions: Is it possible for molecule to be achiral even though molecule has chirality center? Is it possible for molecule to be chiral even ...
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2answers
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How to quantify the difference between two xyz files for the same molecule?

Sometimes I encounter xyz files with slightly different coordinates, for example, before and after optimization. What is the easiest way to compare how different are they? In the first approximation,...
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122 views

How to rationalise the resonance structures of nitrogen dioxide?

The following image depicts resonance in $\ce{NO2}$ molecule: I don't know if it is obvious or not, but I'm puzzled by this structure. I've read about the structure of the $\ce{NO2}$ compound, but it ...
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2answers
100 views

Long linear molecule with alternating elements? [closed]

In the classic freshman physics text Electricity and Magnetism by Purcell, one of his first examples is the computation of the electrical binding energy of a $\ce{NaCl}$ crystal. He models the crystal ...
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Which has the greater N–O bond length, NO₂⁻ or NO₃⁻?

Which has the greater N–O bond length, $\ce{NO_2^{-}}$ or $\ce{NO^_3^{-}}$? I don't understand why the N-O bonds should be of different lengths in these two molecules (don't the same bonds have the ...
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Choose the molecule with the strongest bond

Choose the molecule with the strongest bond: $\ce{F2, Cl2, Br2, I2,}$ or all are equal. All of them are nonpolar-covalently bonded, so I had thought that the answer would be "all are equal". However,...
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1answer
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Do molecules containing only carbon exist?

Why doesnt carbon forms bonds with itself to form a molecule. Carbon shows the property of catenation then why doesnt it form a cyclic molecule as : ...
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1answer
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Are there gases that spontaneously combust when mixed with oxygen? [closed]

Is there a known gas that would combust by there mere action of mixing with oxygen? So, we could put this hypothetical gas in a balloon, and if the balloon popped, it would combust and explode.
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778 views

Discrete molecules [closed]

I came a across a passage in my textbook on Formula Mass topic which mentioned something about discrete molecules. Some substances such as sodium chloride do not contain discrete molecules as their ...
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1answer
133 views

How do I visualise bicyclo[4.4.1]undeca-1,3,5,7,9-pentaene?

While reading my organic chem book, I came across this compound: Since this is an exercise question, I do not know the name of this compound. I am unable to visualize this compound (how it looks out ...
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1answer
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At what temperature can molecules no longer form?

// hyper simplistic terminology in use for the question - apologies. Molecules are formed by atoms bonding together, and those bonds have an equivalent energy. At what temperature does the thermal ...
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Calculate concentrations in a system made up of molecules in order to calculate ionic strength

I understand how to calculate ionic strength where there are concentration data in molality or molarity units available and where the system is made up of only two components. However, I have been ...
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1answer
650 views

How many molecules are there in 17.53 grams of NH4ClO4? [closed]

How many molecules are there in 17.53 grams of $\ce{NH4ClO4}$? I get to 1 mol = 118 then I get stuck.
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1answer
348 views

Why are long oxygen chains unstable? [duplicate]

H-O-H (water), H-O-O-H (hydrogen peroxide), H-O-O-O-H, H-O-O-O-O-H, etc. This is analogous to hydrocarbon chains, methane, ethane, propane, butane, etc. Note the Hydroxygen Chains satisfy 2 covalent ...
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How would you write the empirical formula of an ion?

How would you write the empirical formula of e.g. X2Y42-?
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71 views

Collision rates between two molecules in a liquid

How would I calculate the collision rate between kaolinite and amylopectin particles in a liquid with a density of ($\pu{1.01g/m^3}$) and a viscosity of ($\pu{0.000434 Pa s}$)? I know this is related ...
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1answer
945 views

Calculating the Radius of a Molecule

Assuming the molecule is a sphere, would the radius of amylopectin be $9.17*10^{-22}~cm^3$? I arrived at this answer by deriving the molar volume by dividing the molar mass ($828.72~g/mol$) of ...
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1answer
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Finding molecules that you randomly create using a modeling kit

I recently bought https://snatoms.com/ (which is just a real-life modeling kit for atoms/molecules) and was just keen on learning about chemistry in general. I often randomly join atoms to make up ...
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2answers
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What is the difference between ''1 C atom and 1 mole of C atoms?'' [closed]

Does 1 C atom mean 1 single C atom out of Avogadro's number of C atoms = 1 single C atom out of 6.023 X 10^23 numbers of C atoms? Does 1 mole of C atoms mean Avogadro's number of C atoms = 6.023 X 10^...
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1answer
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What to say 'one mole of C atoms or one mole of C molecules?

What to say 'one mole of C atoms or one mole of C molecules in CO? Please point out if I am wrong here As we know, one molecule of CO = one mole of CO molecules = 6.223 X 10^23 number of CO molecules ...
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1answer
75 views

Is a non-compound molecule a chemical substance?

The Wikipedia definition of chemical substance states: A chemical substance, also known as a pure substance, is a form of matter that has constant chemical composition and characteristic properties....
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How is sulphur trioxide formed and why is it stable? [duplicate]

Structure of $\ce{SO3}$ (sulfur trioxide): In the molecule, if each oxygen atom shares two electrons with sulfur atom then how does the sulfur atom remain stable? It already has 6 valence electrons ...
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1answer
87 views

Calculate the formula, and moles

If $\ce{1.84\times10^{-4}}$ moles of element A was completely reacted with element B to create $\ce{1.231\times 10^19}$ molecules of $\ce{(A3B2)_x}$ a hypothetical compound, what is the value of x? I ...
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1answer
890 views

Do alkali metals not form diatomic molecules?

I know hydrogen forms a diatomic molecule $\ce{H2}$, where the electronic configuration of hydrogen is $\ce{1s}$. But why doesn't lithium also form a diatomic molecule? Its electronic structure is $\...
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2answers
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Are the breaking of bonds simultaneously endothermic and exothermic? [closed]

I understand that energy is NEEDED to BREAK bonds. But don't chemical bonds already have some form of potential energy in them already? So wouldn't it make sense that even though energy is required to ...
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Can the friction of air disintegrate objects if they are accelerated enough?

Can an object be thrown so fast that the individual atoms or molecules separate in air? I mean if you could accelerate an object fast enough, would it disintegrate from the friction of air? If so, ...
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A mole of atoms is the number of atoms whose total weight equals the atomic weight?

My textbook says, a mole of atoms is the number of atoms whose total weight = the atomic weight. There's something in the definition that's confusing me. Now what is confusing me is: Atomic weight =...
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1answer
139 views

Identification of an aromatic compound for a quiz [closed]

I need help identifying this structure for a puzzle. Original text was blurry, so a white overlay was added for readability, though some fragments might be different. Any help or suggestions are ...
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1answer
83 views

Finding $c$ with Dulong-Petit law on non-molecular substance

The Wikipedia article states the Dulong-Petit law as follows: $$c=\frac{3R}M$$ $c$ is specific heat capacity $[\mathrm{\frac J{kg\; K}}]$ and $R$ the gas constant. $M$ is the molar mass in [g/mole], ...
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Why do methane molecules have 15 degrees of freedom?

I've just been learning a little thermal chemistry including the equipartition theorem. As part of this, my textbook discusses how to figure out the degrees of freedom for different chemicals. The ...