Molecular Definition and 545 Threads

Hi guis, i need your help... 1. Homework Statement Evaluate the rotational and vibrational contributions to the heat capacity of a gas of DBr (D=deuterium, Br=mixture at 50% of 79Br and 81Br) at 380 K temperature, knowing that the bond distance is 1.41 Å and the vibration frequency of 1H79Br...

I'm not a molecular physicist, so my speculations are bound to be somewhat naive. I'm only hoping to initiate some discussion around the subject, which I thought might be interesting to all. Now that the electronic absorption spectrum of the atomic anti-hydrogen 1s->2s electronic transition...

Hello everybody, The general expression of molecular Hamiltonian operator for any molecule is: $$\hat{H} = \hat{T}_n+\hat{T}_e+\hat{V}_{ee}+\hat{V}_{nn}+\hat{V}_{en}+\hat{f}_{spin-orbit} $$ where: ##\hat{T}## correspond to kinetic energy operator ##\hat{V}## correspond to potential energy...

I have been searching for ways to calculate resonance frequencies of complex molecules. I know that doing so is extremely complex, especially if that molecule contains many elements, but perhaps it could be feasible to target a specific component of a large molecule, such as a nucleus in a cell...

Hello everyone. I have a weird question regarding the calculation of free energy changes in a multi-step mechanism. Now, if you have a bunch of calculated free energies in gas phase at 1 atm (say, from an electronic structure program) and you want to model in solvent, you need to get them in a...

I have seen many instances of molecular formulas of two or more compounds with a dot between two adjacent molecular formulas like CuSO4.10H20, CaCO3.MgCO3, K2SO4.Al2(SO4)3.24H20 and so on. What does the dot indicate?

So I just had a question about calculating moles atomic iodine when you have the moles of molecular iodine. In the chemical equation IO3-(aq) + I-(aq) + H+(aq) = I2(aq) + H2O(l) Would the moles of atomic iodine be equal to the moles of the molecular iodine? or would the moles of atomic iodine...

In my rough understanding Molecular Dynamics using Classical Newtonian mechanics is a 6N dimensional non linear system. 6N dimension because you have 3 position vectors and 3 momentum vectors for each N particles. Nonlinearity because of the terms in force fields. In principle this system can...

Let's say you have a good personal computer with these characteristics: i7-6700K, 32GB RAM, 256GB SSD, 2 x GTX 970 4GB And let's assume you can run your algorithms, software... for 24 hours. I wonder, if I would be calculating the orbital structure of an hydrogen atom with many electrons...

The Nobel prize in chemistry for 2016 has been awarded "for the design and synthesis of molecular machines." These are fascinating constructions made up of just a few molecules, so they are the smallest machines possible. It is far from trivial to get these things working, especially since...

I want to make my own set of molecular models with balls representing atoms and links representing bonds. Anyone knows of a good software to do this? As for the physical model, what bond angles, bond lengths and ball sizes should I create? I could for example leave atoms as round balls and...

Hello everyone! I am really glad to be part of this group. I hold a Bachelor of Science with Honors in Molecular Biology from the University of Sydney. During the past 10 years, I built a strong career in the business side of research, working as a technical sales consultant, and despite the...

Homework Statement Homework EquationsThe Attempt at a Solution Firstly I tried to find the empirical formula: C : H : O 65.2 : 8.75 : 26.05 (mass) 5.43 : 8.75 : 1.628 (mol) 3.34 : 5.37 : 1 10 : 16 : 3 C10H16O3 This gives a molecular mass of 184. Now with the structure: It has to...

So here is my question, and maybe I am not asking it right, but here we go: If electromagnetism prevents me from actually touching anything at a quantum level, how is it that I can get cut by a knife, or get a road rash falling off my bike? If the negative field of electrons that surround...

Homework Statement According to the kinetic molecular theory: as the distance between the molecules increases, the temperature of a material decreasesthe rise in temperature of a material occurs because the molecules lose kinetic energywhen the molecules within a gas collide they lose energy...

So if energy levels, or eV of electrons, do not change with molecular bonding, how are electrons influencing each other.? In glass, when individual atoms of silicon, sodium, and calcium come together, to form glass, the molecular bonding does not change the energy levels of the electrons for...

Homework Statement Homework Equations Langevin equation (I included all the equations in the next section.[/B]The Attempt at a Solution I do not know how I can proceed from this point. I'm stuck since I have no information on the drag coefficient. Maybe my approach is wrong, and there may...

What home based solvent might dissolve an unknown electron microscope seen insoluble particles ? There are some sort of unknown insoluble particles in our water. Does anyone know of any home remedy acid solution (baking soda and vinegar) that might dissolve these particles ? Please keep in...

I watched many videos and read bunch of answers about this, but I was having a hard time finding an answer to this one point: What is the exact moment an organism realizes that it is under an attack? I understand that there might be a few different types of ways a body can react too. So far...

Homework Statement So for my homework assignment in 'Materials Science and Engineering', We were given the following problem. 1. Li and Ra both are both BCC metals. For this problem assume they form a complete solid solution (even though the very large difference in their atomic size tell us...

Guys I studied Molecular orbital theory based on wave mechanics in lower level as i don't know what is wave mechanics so i saw molecular orbital diagram of boron di atomic molecule in which there are two pi molecular orbitals so my first question was that there must be first a sigma molecular...

Homework Statement Use the Heun method to compute the period of small oscillations about the equilibrium position of a nitrogen atom. xi = 1.1 Um = 7.37 x0 = 1.2 alpha = 2.287 m = 2.325e-26 Homework Equations [/B] U(x) = Um((1-e^(-alpha(x-x0)))^2 - 1) The Attempt at a Solution I was told to...

Consider the image below Does it emit all 3 types of heat in the form of UV, IR and light? At what threshold does light start to appear and what colors should it illuminate? Hypothetically, say I have an induction furnace and is capable of setting frequencies to about 700THz, will it be able to...

In IR spectroscopy, bonds vibrate and therefore there are moving charges and usually a changing dipole. If accelerating charges cause EM waves to be given off due to the changing electric field then shouldn't the vibrating bond be constantly emitting photons and therefore losing energy in a...

I am a professional math and science tutor, primarily focused on math and physics. I used to tutor organic chemistry but gave it up because I didn't want to study orgo an hour per week for the rest of my life. I like general chemistry and have no trouble with most topics, but the way of...

Homework Statement Compute the average number of molecular hits, per unit time, experienced by a square inch of surface exposed to air, under normal conditions. Assume air is a mixture composed of 80% N2, 20% O2, both of which are assumed to be ideal gases. You will have to perform angular...

Homework Statement Book says "Substances with a simple molecular structure do not conduct electricity. This is because they do not have any free electrons or an overall electric charge". Homework EquationsThe Attempt at a Solution I think the statement is a generalization because water is a...

Homework Statement What are simple molecular structures?Homework EquationsThe Attempt at a Solution Simple molecular structures consist of molecules containing fixed numbers of atoms joined by strong covalent bonds. I'm getting confused with all the different structures in chemistry. How...

.. reaction. This may seem a nonsensicle question but I'll go ahead anyway. Say if I have a process that has an emission spectra dominated by excited state molecular emission, can I relate this in any way to the amount / number of chemical reactions occurring? Thanks for any help

Is an oscillating dipole of a molecule the periodic motion of the atoms in the molecule (the oscillating back and forth of a more negatively charged atom and more positively charged atom), or, is an oscillating molecular dipole just oscillations in electron density? I just can't get a clear...

Using the Maxwell-Boltzmann equation above, there is an example in my book (Giancoli 4th edition p. 481) where they use this to find the average velocity. I understand that it would just be the sum of all the speeds of the molecules divided by the number of molecules. But then I'm having...

Hello, this is one of the problems in my laboratory manual and it has been killing me. I've been working on this all week. It's due tonight, so hopefully it's not too late... 1. Homework Statement Explain why specific heat is "specific", and how it gives a relative indication of molecular...

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 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...

Rather a short question, but what kind of design can be used for a narrow potential surface curvature in molecules?

I am a rising senior at a small liberal arts college, with an incredibly small (and therefore unrecognized) physics program. I am seeking advice regarding which Ph.D programs are within my reach. I plan on applying to AMO (Atomic, Molecular, and Optics) Ph.D programs with the intention of...

Hi everyone. Most of what I've read on thermal neutron cross sections talks only about what isotope makes up the neutron target. Likewise, all of the cross sections listed on Sigma: http://www.nndc.bnl.gov/sigma/index.jsp?as=9&lib=endfb7.1&nsub=10 ... are broken down just by isotope. However...

Homework Statement I'm having trouble figuring out if a solid is a molecular solid or network covalent solid. Classify the following as a network covalent solid or a molecular solid: 1. CO2 2. SiO2 Homework Equations Molecular solid held together by intermolecular forces Covalent network...

molecular solids are bonded intramolecularly by: 1_primary bonds 2_secondary 3_van der waals 4_all of them

Hey! So I'm a little fuzzy on my understanding of MO theory. One question I had on my study guide said that according to MO theory, overlap of two s atomic orbitals produces _________. I know the answer is one bonding molecular orbitals and one antibonding molecular orbital. Why is this? Also I...

Hi there! Is there an online, hopefully free resource (preferably textbook) that details the process of molecular modeling? Specifically, computationally performing geometry optimizations, vibrational analyses, calculating Raman spectra, detailing the theory behind Hartree-Fock, DFT, post-HF...

As I've been reading up on fluid mechanics recently, I've discovered several different molecular models which attempt to explain heterogeneous fluid flow from a molecular level. Classical fluid mechanics assumes that hard body approximation- that atoms are hard spheres knocking into each other...

The ionization energy of H2 is 1488 kJ/mol. How strong of a DC electrostatic field would be need to ionize H2 molecules all at a distance 'd' from the source of the field? What I am asking is how to convert the known unit (joule) into a measure of an electrostatic field since electric fields are...

So basically I was wondering whether it's possible to get the expression of ideal gas using molecular flux equation which is ##\phi = \frac{1}{4}\bar{v}n##. The derivation should be straightforward. I need to get the expression of pressure. Because the flux by definition already gives the rate...

Is it true, as someone says, that molecular hydrogen in its fundamental state don't (almost?) absorb in the frequencis of the Balmer series of atomic hydrogen emission spectrum? Thanks. -- lightarrow

Hello all I have an exam coming up this week but there's something that I don't understand: Let's take methane, for example. If I understand it correctly, the bonding orbitals of carbon are all hybridized to sp³ orbitals and overlap with the 1s orbital of four H atoms. Does the orbital of...

Plzz explain me molecular orbital& relation beetween atomic

I'd like to ask a couple of questions. As a solid object gets bigger, the molecular orbital (combinations of all single atom orbitals) has greater size too? For a one inch square object (of closely packed molecules like crystals), what is its molecular orbital size compared to a one foot square...

Not a homework question, just curious. My book says that bonding orbitals from from constructive interference while antibonding orbitals from destructive interference. Since constructive interference increases amplitude, what increases in amplitude from the combination of bonding orbitals? It...

Molecular mass of water is constant i.e mass of one mole of water i.e 18 g Molar mass is the mass of a substance depending on how many moles of substance is taken into consideration. Ex. A mole of H2O: 18 g Two moles of H2O: 36 g Three moles of H2O: 54g and so on. Right? And molecular mass...