Molecule Definition and 439 Threads

Could you explain why an H2O that attacks Ni(CN)4 ^(2-) (in square planar) (which has D4h symmetry) at one of the axial sites would have A2u symmetry? I know that the "HOMO" for the p orbital of the H2O would be a p orbital. I also tried to link that electron pair to an irreducible...

The word molecule has several definitions, but which one is considered the right one? The biggest question is if a single atom is still a molecule. Some call a helium atom a (monatomic) molecule. But others state that a molecule is a bond between two or more atoms. Some also say a molecule is...

Homework Statement Experimental data for the heat capacity of N2 as a function of temperature are provided. Estimate the frequency of vibration of the N2 molecule. Homework Equations Energy of harmonic oscillator = (n+1/2)ħω C=7/2kB Average molecular energy = C*T But this is an expression...

Hi all, If a camera images a fluorescent molecule gaussian function with diameter roughly 300nm and each image pixel represents 160x160nm how could you say with higher precision where the molecule is located within that pixel. For instance if the localisation precision turns out to be 40nm how...

Homework Statement I have a methyl orange molecule. Then my problem says that "wool is a protein, a naturally occurring polymer made up of amino acids with ionized side chains. cotton is a naturally occurring polymer made up of glucose units with hydrophillic groups surrounding each glucose...

Hi, How did they break down the following summation? When finding the vibrational partition function ofa diatomic molecule it was approximated that the energy levels of the vibrational part of the diatomic molecule were harmonic and therefore the energy equation for a harmonic oscillator was...

I mean what is the most common way people do this? I was using something called chemdoodle but i couldn't figure out how to number the atoms. Is chemdoodle the best or something better? thanks

Hello everyone! The goal is to calculate the length of octanthiols in full stretched all-trans configuration. The structural formula is HS-C_7H_17-CH_3 witch is an alkyl chain terminated with sulfur. I used Avogadro software to build and model the structure. After i let it measure the distance...

Hello everybody, My question is about the water molecule. Is the isolated H2O molecule has a non-vanishing element \beta_{ijk} in its first-order hyperpolarizability tensor \beta ? Thank you everybody.

Homework Statement Potential energy in a molecule[/B] (b) The figure below shows all of the quantized energies (bound states) for one of these molecules. The energy for each state is given on the graph, in electron-volts (1 eV = 1.6 ✕ 10-19 J). What is the minimum amount of energy required to...

Homework Statement Calculate the rms speed of one nitrogen molecule at 27 Celcius Homework Equations sqrt(v^2) = sqrt((3kT)/(m)) The Attempt at a Solution sqrt(v^2) = sqrt((3kT)/(m)) k = 8.62*10^-5 eV/K T = 300 K 3kT = 0.078 eV m = 14 g/mol m = 0.014 kg/mol 3kT/m = 0.078 eV/0.014 kg/mol =...

Hello everybody, As I mentioned in the title, it is about molecular symmetry and its Hamiltonian. My question is simple: For any molecule that belong to a precise point symmetry group. Is the Hamiltonian of this molecule commute with all the symmetry element of its point symmetry group...

I'm trying to understand the meaning of kT (energy) in molecular systems, how to define the temperature of an individual molecule, and how a molecule receives thermal energy or dissipates thermal energy. Here is my 'gendanken': One molecule is floating in a box, in vacuum. The temperature of...

Let's say a molecule of hydrogen ends up in a blast furnace. It breaks into atoms, which then might combine with oxygen or some other element. What killed it? a. Internal vibration shook it apart. b. Another molecule smacked it right between the atoms and cleaved it. c. It absorbed a photon...

Hello, Internal energy can be defined theoretically for one molecule (U = 1/2 Kb T) for example but entropy is defined for a system thus for many molecules. Then we define temperature equal to δU / δS but here U can be defined for one molecule, so S can also be defined for one molecule? How...

Homework Statement How many oxygen atoms are there in one molecule of oxygen gas? How many oxygen atoms are there in one mole of oxygen gas? Homework EquationsThe Attempt at a Solution [/B] There are 2 oxygen atoms in one molecule of oxygen gas. There is 6.02x1023 oxygen atoms in one mole of...

Hi, So for a piece of maths coursework I am thinking of trying to calculate the surface area of an atom or molecule. I do not know whether it would be viable because there isn't a clear boundary for an atom/molecule due to the electron clouds. However I wanted to know if I could do something...

Ar STP Every gas occupies same volume of 22.4 L but how it can be because every gas molecule has different size right? So they should occupy different volumes right? If I'm wrong at any point then please correct me

OK the atmosphere by definition envelopes the earth.The force keeping it here is solely gravity. The "force" opposing this is diffusion across a pressure gradient into the vacuum of space. Assuming that is correct how could I prove this other than looking out the window. Newton's law of...

Homework Statement Which statement describe a polar molecule? a. The molecule has an uneven distribution of electron density [ans] b. The molecule has a linear polarity without charge c. The molecule has a tetrahedral geometry d. All of the above The Attempt at a Solution I would personally...

Dear PF Forum, I have questions about carbon based life and molecule back bone. Is it true that all life on Earth are carbon based? If it is true, why? Is it because carbon is halfway in periodic table? 4 valence? What about Silicon, Tin and Germanium? They have 4 valence, why life is not based...

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...

hi I have been given an assignment at school to look at various ways heat is transferred through liquids. I'm interested in looking more into the kinetic energy of molecules and how their vibration causes heat, I would like to know if there is a device I could use to record the frequency of...

hello! it is known that static electrical field can change the direction of movement of water dripping, etc I suppose this can also happen with other molecules that are dipoles or somehow influenced by electrical or magnetic field my question is what are the equation(s) that describe this...

What is the relationship between the nitrogen inversion (or "flip-flop" or "turning itself inside out") and the associated microwave radiation of the ammonia molecule ?

In the discussion of calculating specific heat for a solid, it is assumed that the whole solid body is a molecule with N atoms and the Hamiltonian of this solid is similar to that of a molecule with N atoms, i.e. ## \mathcal{H}_1=\mathcal{V}^{*}+\sum_{j=1}^{3n}...

In chemical formulas of various inorganic compounds there are molecules of water .I wanted to know is it important to remember the number of moles of water in chemical formulas of inorganic compounds.

Consider a triatomic molecule with three identical atoms that are bound together with each atom at its own corner of an equilateral triangle of edge length a. An added electron on the molecule can be put in an identical atomic orbital on any of the three atoms. Denote the atomic states in which...

Will the air molecules attain a new fixed acceleration at a specific temperature? Or does it attain a new fixed velocity at a specific temperature?

My textbook says, "alkynes are non-polar polar and thus insoluble in water". If there is a long alkyne molecule, why would its solubility matter if it were polar or non-polar?

Homework Statement In the spectrum of the blue part in a candle flame, there’s a violet emission at 432 nm due to excited CH* molecules (chemiluminescence). Why 432? Why not 400 or 500? There are emissions at 436, 475 and 520 nm too. Why these numbers? 2. The attempt at a solution Is it...

Homework Statement Under certain conditions the interaction between a "polar" molecule such as HCl located at the origin and an ion located along the x-axis can be described by a potential energy U=−bhttps://s3.lite.msu.edu/adm/jsMath/fonts/cmmi10/alpha/144/char3D.pngx^2, where b is a...

Hello everybody, I am new in this forum and also new with english langage, so don't be shocking if I write like a baby for you. I am little better for understanding when I read. My question: Books always tell us about the only ground state of ammonia molecule but never on its excited state...

Homework Statement The temperature of an ideal gas is 00C and the pressure is 1[atm]. imagine every molecule is enclosed in a cube, what's it's side length? Homework Equations PV=nRT Avogadro's number: 6.023E23 The Attempt at a Solution I assume volume of i liter: $$1[atm]\cdot...

Hello, Some years ago I have heard from the brazilian physicist, Constantino Tsalis, that the DNA molecule, if unfolded and made to lay in a line, will be close to one meter long. But he said that thermodynamically this configuration could be taken as an impossibility, for no such long and...

The atmosphere consists of two toxic, and unfortunately abundant gases in our atmosphere. Carbon dioxide and methane. Carbon dioxide produced by factories are not needed in the atmosphere and cause harm. So is methane. Acegikmoqsuwy and I thought of an equation to solve this problem: CH4 + CO2...

Homework Statement What is the mean free path of an N2 molecule in an ultra-high-vacuum chamber at a pressure of 10-10mbar? Homework Equations λ=1/(√2)nσ number density n, collision cross-section σ p=nkT pressure p, temperature T σ=πd2 d molecular diameter The Attempt at a Solution...

How do you strengthen and weaken hydrogen bonds in water aside from changing its temperature? Could you add any solutes to do so?

Hi, I know what are the steps to determine if a molecule is polar or not, but I'm having one small problem. When I have determined teh geometrical shape of my molecule and drew the vectors of the polar bonds that goes from the least electronegative atom to the most electronegative atom, how...

Homework Statement Suppose an oxygen molecule traveling at the speed of 484 m/s bounces back and forth between opposite sides of a cubical vessel 0.1 m on a side. What is the average force the molecule exerts on one of the walls of the container? Homework Equations F=p/t The Attempt at a...

Hello, for octane (C8H18), how can you tell whether or not it is polar or non-polar without drawing a lewis structure diagram? also, if you absolutely need to draw one, what is the easiest way to go about drawing a more advanced molecule like octane? I can draw simple molecules and find their...

Homework Statement When displaced from equilibrium by a small amount, the two hydrogen atoms in an H2molecule are acted on by a restoring force Fx=−k1x with k1 = 500N/m. Calculate the oscillation frequency f of the H2 molecule. Use meff=m/2 as the "effective mass" of the system, where m is the...

Homework Statement The distance between the both nucleons in the H2 molecule is 0.0741 nm The energy for the 3 lowest radiation levels of the molecule are: ##E_{0}=0 \\ E_{1}=0.0151 eV \\ E_{2}=0.0453 eV## How many revolutions per second does the molecule rotate with in the different states...

Let's say there was a Lattice L of a certain molecule P. The molecules are spherical and are in static equilibrium. L is in a bucket shape, with the R1 and R2 of the two bounding areas circular areas that are along the x,y plane at z(R1) = Z1 and z(R2) = Z2. The density of the structure is known...

Hi, I am having trouble with this concept... "A mean speed (c) is calculated by multiplying each speed by the fraction of molecules that have that speed, and then adding all the products together. When the speed varies over a continuous range, the sum is replaced by an integral. To employ...

Homework Statement "A molecule has its dipole moment aligned with a 1.8 kN/C electric field. If it takes 3.5x10^(-27) J to reverse the molecule's orientation, what is its dipole moment?" Homework Equations Potential energy of dipole in an electric field U = -p*E = -p*E*cos(theta) U...

Hey, guys, I have just watced a fantastic animation of the microscopic process of sound wave traveling, in which model was described as many balls connected by springs. But the problem is what we learned in thermodynamics chapter is that there is no bonds between molecules in gas, then how...

Hello! 1. The problem statement and all variables AIM: Calculating persistence length P of a single dsDNA molecule from a data set of force F (to the molecule) vs. extension x measurements. Experimental background: pN forces were applied to a single dsDNA molecule spanned between two...

Here attached is a question from my exam. My TA removed 1 point out of 7 for a reason. Can anyone decipher for what? There's the writing in red but it is illegible to me. I don't understand to what he refers by 8 and 6 t or +, or whatever he wrote. http://imgur.com/igpyp8V Or can anyone write...

I came across this problem in University Physics: (a) Oxygen 1O22 has a molar mass of 32.0 g>mol. What is the average translational kinetic energy of an oxygen molecule at a temperature of 300 K? (b) What is the average value of the square of its speed? (c) What is the root-mean-square speed...