Molecules Definition and 561 Threads

Homework Statement Which of the following is closest to the mean distance between air molecules at room temperature and pressure (298 K and 101325 Pa)? Assume air is made of 79% N2 and 21% O2 by moles. A 0.4 nm B 4 nm C 40 nm D 400 nm E 4 μm Homework Equations PV = nRT The Attempt at a...

It seems like a very basic question. I've read about OH molecules in the context of astrophysical masers and perhaps it is already known, but the notation always omits the "-" superscript to denote the molecule as being an ionized one (i.e. an anion). Just to clarify, are OH molecules in masers...

I have been reading a thread regarding the difference between rocks and people?! A lot of the comments reffered to various understandings of various definitions. I am considering the definition of 'living'. Do vibrating molecules indicate life? Or do we refer to cell structures only (I.e. plants...

can H2s form hydrogen bonds i read that H2s can , but I'm not so sure about it .

In order for a cell to function, chemical signals and other types of molecules need to get from one area of the cell to another. mRNA needs to get from where it is created to DNA, and then from DNA to the ribosomes and other locations of the cell. Chemical signals need to get from one areas of...

Is H2O a biomolecule?

Homework Statement Consider a gas of molecules of mass m at equilibrium at temperature T. Obtain an expression for the fraction of molecules having kinetic energy e = 1/2mC2 in the range e to e + de. This is problem 5.3, page 48 of Vincenti and Kruger's Intro to Physical Gas Dynamics Homework...

Firstly, i know this question is worded strangely, i wrote noticeably tangible because a molecule is a tangible thing but not visible to the eye without equipment. But my question is, how do we get a single molecule, and increase its size to be visible? For example a cup of water is like a...

Hi, A silly techiniacal, very basic but logical question. Trying to understand since long but unable to justify myself. Can u help? Deferent gases have deferent molecular size, then how is it possible that equal volume of deferent gases have same numbers of volume at standard temperature &...

what is the chemical composition of common processed paper and what does the molecule's structure look like?

I was wondering if it is possible to image the motion of individual air molecules? What I am picturing is using a laser to illuminate a volume of air, and using scattered light to measure the velocity of individual air molecules through the doppler shift of the scattered light. It seems that...

I was researching the relationship between magnetic dipoles and chemical bonding and I came across a very interesting paper. I'm hoping some of you can shed some light on how magnetic fields are making dissociation of a molecule possible and how to measure it...

Hello all. I am working on a research project involving the Stark effect and its application in molecular guides and came across a bit of math in a paper that I don't understand. In this paper http://arxiv.org/abs/physics/0310046 there is an equation in the introduction concerning the electric...

We know that molecules absorb light based on their electronical, rotational, and vibrational transitions and the governed transition rules (so that each molecule has its own "fingerprints"). But I do not know why it happens? Lets simplify it a little: A methane molecule, for example, is...

I am a year 1 undergrad physics student helping my professor to do some small project. So I have to know basically what she is doing. Yet, the paper about Feshbach molecule is kind of a bit difficult for me to understand. I found some jargons like open channel, close channel... What are these...

Are there any complex molecules that are not biomolecules and don't get "involved" with organisms and life building?

Homework Statement In the balloon with volume 4 liters, is 1 gram of hydrogen. How molecules of this gas as found in 1cm3, if the molar mass of hydrogen is 2g/mol? Homework Equations pV=nRT The Attempt at a Solution in my book the solution final is 7.5*10^19 molecules/cm^3

I am working on a paper about Ammonia masers. It looks like Ammonia molecules are usually found in a superposition of even and odd parity states that are eigenstates of the inversion potential. That is the double well potential of the Nitrogen to tunnel through the Hydrogen plane. If it...

Hello everyone. I am a 14 year old student and am truly fascinated by chemistry. As I tried various software, they all had a very complicated UI (User Interface) and confused me a lot as a younger student. After searching a lot, I decided to make my own chemistry software. This is the final...

Homework Statement N2 molecules absorb ultraviolet light, but not visible light. I2 molecules absorb both visible and ultraviolet light. Which of the following statements explains the observations? a) More energy is required to make N2 molecules vibrate than is required to make I2 molecs...

How does one go about finding the spin number for a molecule like water for example? Do we consider the spin of the nuclei (e.g. proton, neutrons), and also look at which electrons are shared and not?

I have searched about this topic all over the internet and non of them seem to explain how vapor pressure is equal to atmospheric pressure. All I need is some forces diagrams and some explanations. How when we increase the vapor pressure it makes the liquid boil faster? Isnt the vapor pressure...

Homework Statement A circular cylinder of height H is filled with monatomic gas molecules at temperature T. The cylinder stands on the surface of the Earth so that the gas molecules are subject to the gravitational field g. (a) Find the average height, z , of the molecules in the cylinder as...

Dear All, May anyone please advise me to the following questions in case of diatomic molecules: 1. How do we choose which Hund's case ((a), (b), or (c)...) that best describes a particular diatomic molecule? 2. How can we deduce from Hund's cases molecular electronic states (2s+1)ΛΩ (e,g...

In class today, we were talking about the Kinetic Molecular Theory and the combined gas law. I was understanding everything until our teacher threw in a question that confused me really bad Suppose we fill two balloons with Helium gas. One of them is filled 5 liters of He and the other to 10...

Homework Statement As attached. Homework EquationsThe Attempt at a Solution I chose A but the correct answer is E.(Actually I thought both of them were correct) From the graph provided,it is clear that the turning point corresponds to the largest proportion of molecules,so is the corresponding...

In molecules, the system (say dna or ribosomes) environment are the cells.. id like to know how much is the momentum basis selected and how this can affect the molecules energies and to what extend and actual examples of that in this internal human body decoherence scenerio. Thank you.

Say you use a water mist spray bottle against a egg smell, do the water molecules crash into the scent molecules and bring them down? What about if the water has mixed into it essential oil? How does the spray interact and affect the scent molecules? Does a air freshener that you can buy in the...

Homework Statement Hello, I just need help figuring out how to calculate the work done by the gas molecules for my physics homework :) Formula given: W=Px∆V (W=work, P=pressure, and V=volume) What I know: So my calculated volume is 1.7x10^-22m^3. Pressure=0.25 A t m (atmospheric pressure) I...

I'm thinking of taking a course called Atoms, Molecules, and Solids this semester and I wanted to get a feel for the material beforehand to see if I'll like the course. If anyone could recommend a textbook based off this course description, I'd appreciate it: Quantum theory of atoms...

Hi! is there any microscope or images in which we can see how a matter reacts as it is heated? And how was it proved that when matter is heated their particules vibrate faster?. Tahnk you!

Homework Statement Pressure in vacuum is 10^-3 Torr. External Pressure is 1atm and 300K. Pinhole of 10^-10cm^2 made in vacuum. Assuming all molecules striking hole pass through, how many molecules leak into vacuum in 1hour? Answer: 10^17 molecules Homework Equations Flux = <v>*N/4V Rate = Flux...

Homework Statement A closed vessel contains liquid water at equilibrium with its vapor at 100C and 1 atm. 1 gram of water vapor occupies 1670cm^3. Hvap = 2250Jg^-1. How many molecules are there per cm^3 of vapor?How many vapor molecules strike each cm^2 of liquid surface per second? Homework...

Homework Statement A bottle of nail polis remover contains approximately 2.5 mol of ethyl acetate (C4H8O2) How many atoms are in the bottle? Homework Equations ? The Attempt at a Solution Would there just be 14 atoms?

Hi there, I'm studying for IGCSE Chemistry and I'm a little confused with Bonding/Molecules. My textbook says: "Molecules are held together by covalent bonds" I'm a little confused by this as I thought a molecule was formed when two or more atoms (same or different elements) join together...

during my reading of ender's game, there was a device that could split molecules and cause a chain reaction of destruction. this seems possible yet impossible to me. can such a weapon be created and if so what causes the reaction to be so destructive.

Homework Statement The question I'm working on is: If a layer of oleic acid is considered to be one molecule thick and the molecules are assumed to be essentially cubes, how many molecules would fill one cubic centimeter? Homework Equations \[/B] I've found the volume and area of the acid so...

So I am taking the second semester of intro physics and Moles,Molecular mass, Number of Molecules is killing me. I am not really able to solve my homework because I can never get these quantities down. I asked my professor for help during offie hours, however he said he teaches physics not...

Homework Statement Homework Equations Pv=nRt The Attempt at a Solution I already calculated V for a single molecule = 3.99x10^-23 m^3 and the cubic root of this volume gives 3.42x10^-8 m. However, I don't understand what I should do next. What does it mean to compare the value I obtained to...

Homework Statement Which solid-line curve most accurately represents the distribution of molecular energies in a gas at 500 K if the dotted-line curve represents the corresponding distribution for the same gas at 300 K? Homework Equations - The Attempt at a Solution Not sure how this...

Do just electrons emit photons/radiation. Or do atoms and molecules emit photons as well? Just can't get a clear answer on this. And if atoms and/or molecules also emit photons, can you please explain what causes them to?

I have several questions about the scattering of light. Air molecules scatter sunlight and makes the sky blue, many books say that the air molecules are oscillated by E field and so they becomes sources of EM wave. Is it because the air molecules have charges? I wonder if air molecules or...

Hi, friends! 1. Homework Statement : I have found an exercise where one should calculate the ratio ##N_{v_{\text{e}}}/N_{v_{\text{rms}}}## between the number of molecules having escape speed ##v_{\text{e}}=\sqrt{(2G M_t)/r}## (where ##M## is the mass of Earth) and those moving at the root mean...

Pure water is not an electrolyte. This is because the hydrogen atoms and oxygen atom will not dissociate into individual charged particles. Why won't they dissociate?

It is usually said that molecules are spherical in shape, that is what we learn from our textbooks. May be what they are saying is true but only in the case of a monatomic molecule. If one considers a diatomic molecule there are two atoms that means two spheres and if it is polyatomic there is...

I was wondering how Rotational Spectra of diatomic molecule can be related to Heisenberg Uncertainty principle (Qualitatively). Being a QM model where rotational energies are quantized, there should be a qualitative reasoning on lines of the uncertainty principle, right? Anyone can direct me to...

What is the velocity distribution of evaporating H2O molecules? It can not be Maxwellian.

Supposed to be because they have a zero dipole moment... Dipole moment is variously described using neutral systems of pairs of opposite charge, or single items with charge, but I am finding no explanations of same charge pairs I understand.. Wiki states: "To show a vibrational spectrum, a...

Hello Everyone, I have been recently calculating the static electric dipole polarizability αD of a polar diatomic molecule, but I was wondering how to calculate the components of the dipole polarizabilities αParallel and αPerpendicular of diatomic molecules? Any help is really appreciated...

I haven't been able to figure out how to approach this. It is actually a real-world problem.but I have simplified it a bit to make it easier to explain. A container with helium gas of pressure Pc in it is located in some environment where the surrounding air is at a pressure is Pe and...