Molecule Definition and 439 Threads

Hello, I was confused about which bond is stronger, ionic or covalent... thinking and searching about that, I found (or better, realized) that when we talk about the boiling point of water, its just that it's INTERMOLECULAR forces get weaker, not the covalent bond present between the ATOMS ...

Hi all, I consider a square planar molecule such as XeF4, Xe atom is at the center, F atoms are at the corners of a square. In the character table of D4h group that XeF4 belongs to, I see that there are two C4 axes but I only can find one that goes through the Xe atom and is perpendicular to the...

Hi, Homework Statement I am trying to determine the size of a molecule..by doing the oil drop experiment where we drop a tiny droplet of oil on water covered with a thin layer of powder...and then make calculations based on the diameter of the circle... the droplet forms in oil. The Attempt...

Suppose two particles or molecules are generated (produced) together. If one molecule is taken away from the another, let us say to another city. If we make some certain changes in anyone of them, e.g if we change its motion if it was in clock wise and we change it to anti-clock wise. So by...

When calculating the kinetic energy of a rotating water molecule (translational and vibrational motion not important here), am I correct in assuming that you do all the calculations from the center of mass and analyze each axis of rotation (x,y,z)? The bent geometry is throwing me off! Any...

When calculating the kinetic energy of a rotating water molecule (translational and vibrational motion not important here), am I correct in assuming that you do all the calculations from the center of mass and analyze each axis of rotation (x,y,z)? The bent geometry is throwing me off! Any...

Any idea that this molecule is? Fig.A shows the molecule and the electron orbitals and bonds. Fig.B is the same image with very approximate bond angles and molecular geometry angles. All the angles are close approximations. The angles are written in black and the number of electrons are in...

i need help to find : 1) a surface area and volume of a c60 molecule. Assume the structure is a truncated icosahedron (Faces=32, Edges=90 and Vertices=60). The mean c60 diameter is 0.68nm but Van der Waals diameter is closer to 1nm. 2) electronic properties of c60 molecule, like how many...

Homework Statement Two identical atoms in a diatomic molecule vibrate as harmonic oscillators. However, their center of mass, midway between them, remains at rest. 1)Show that at any instant, the momenta of the atoms relative to the center of mass are p and -p 2)Show that the total...

How do individual oxygen atoms combine to form the O2 molecule? Can it be done with heat?

The question is: Which substance has the highest melting point? (A) CO (B) CO2 (C) SiO2 (D) P2O5 The answer is C but I don't know why (you obviously can't look up the values). I need to be able to figure these types of questions out regardless of the...

hi, i need to explain how molecules of ethene combine together to form a poly(ethene) molecule? would it be because the double bond is broken and 2 bonds them placed on the outside of the Carbons (C)? if this is not correct could someone please let me know where I am going wrong! thanks!

Homework Statement Name the following (organic) molecule: http://img827.imageshack.us/img827/1883/organicmolecule.png Uploaded with ImageShack.usHomework Equations The Attempt at a Solution Would this be 3-pentene? The root has to be "pent" because that's the longest carbon chain, right?

Hi there! I'm studying the hydrogen molecule. According to the MO technique I start from one-electron molecular orbitals to construct the wave function of the entire molecule. Afa hydrogen is concerned, I can construct two ^1\Sigma_g orbitals: \Phi_A=\Phi_g(1)\Phi_g(2)\chi_{0,0}...

Homework Statement Using specific heat data for a nitrogen molecule, estimate then vibrational frequency of the diatomic molecule Homework Equations C= 3N_a k = 3R The Attempt at a Solution unable to attempt a solution

Does anyone tell me why the potential energy increase(becomes more positive) when two atom put closer to each other which is smaller than the equilibrium bond distance while potential energy decrease(becomes more negative) when two atoms put closer to each other (which is close to equilibrium...

Hi everyone, I'm wondering if its possible to design a molecule that re-arrange on an electromagnetic (non-visible and radio) signal, and revert back to original structure when signal stops. Thanks in advance

Ok I can see the 5 end is negative, is the 3 end positive due to OH. So in other strand this goes other way round. Is this what they mean when they say there is reverse polarity in a DNA molecule. Thanks!

The energies of the ground and third level of a certain molecule are 1.15 x 10-20 J and 4.31 x 10-20 J respectively. What is the frequency (in Hz) of the photon emitted when this molecule drops from the third vibrational level to the ground level? You don't have to solve it. Could someone...

Hi, If the normalized 1D wave-function of hydrogen atom for n=1, l=0, m_l=0; \psi_{1s}(x)=\frac{1}{\sqrt{\pi} a_{0}^{3/2}}e^{-x/a_{0}} and probability distribution of wave-function, \mid\psi_{1s}(x)^2\mid so integration of rho over all x should give the number of electrons which is equal to...

Hi, I consider harmonic model of diatomic molecule: two atoms connected with a massless rod. Let one axis be along the rod, other two perpendicular to it. Let rotational velocity have components only trough perpendicular axes. In one book it is said that rotational energy of such diatomic...

Look for yourself. If a member posted one of these, he'd probably get an infraction. Cummingtonite, ok it's a mineral. http://www.chm.bris.ac.uk/sillymolecules/sillymols.htm

Homework Statement Hi guys I know the molar mass (i.e. g/mole) of H and O, but from this, then how do I find the volume of 1 water molecule? I know the densities of H and O as well, from which I can find the volume of H and O. Do I just add these, one of V_oxygen and two of V_hydrogen (I...

Homework Statement The potential energy V between the two hydrogen atoms ( mH = 1.672*10^(-24) g) in a hydrogen molecule is given by the empirical expression  V = V0 [ exp(-2a(r-r0)) - 2exp(-a(r-r0))] where V0 = 7*10^(-12) erg, a = 2*10^8 cm-1, r0 = 8*10^-9 cm. (a) Estimate the...

Homework Statement The energy of a rotator ( a dumbbell-shaped object) is given by L^2/2I, where L is the angular momentum and I is the rotational inertia (moment of inertia) of the dumbbell. Consider an HCl molecule, in which the atomic weights of H and Cl are 1 and 35, respectively, and...

Homework Statement Okay here's the problem, normally I can get all this stuff, but right now this is blowing my mind, partly because its too general. "In other problems and examples in the textbook we found the effective spring stiffness corresponding to the interatomic force for aluminum...

How can I calculate the attractive electric force between the unlike atoms of a water molecule? Would I use Coulomb's law? Using Coulomb's law: I don't understand the radius I would use?

I know that the selection rule is : \DeltaJ = +/- 1 but our prof said that according to some quantum mechanical calculations the odd values of J are not allowed. So, the allowed transitions are : J 0 <-> 1 ; 2 <-> 3 ; 4 <-> 5... as...

Homework Statement Spectroscopic data (rotational-vibrational lines) show that the hydrogen fluoride molecule has a vibrational frequency of 7.8x10^14 rad/sec and a moment of inertia of I=1.35x10^-47 kg.m^2. Find the relevant characteristic temperatures of the HF molecule. Homework...

I've studied a little organic chemistry but I couldn't figure it out. I've never seen it before but I'm sure it's simple to name, yet I couldn't find anything on Google.

Does there/or could there exist a molecule made only of carbon, that is smaller than C20?

[SIZE="2"]I'm not a science student. So, please keep your reply simple and straightforward. Thank you. A fat molecule is made up of two types of molecules: glycerol and fatty acid. There are different kinds of fatty acids. Are there also different types of glyceol, does it come only in one...

Homework Statement a) Find the probability that a molecule will travel a distance at least equal to the mean free path before its next collision. b)After what distance of travel since the last collision is the probability of having suffered the next collision equal to 1/2? Homework...

Homework Statement Value of the Van der walls constant for the oxygen is 32 cubic centimeter. Find the diameter of the oxygen molecule? Homework Equations thermodynamics problem The Attempt at a Solution

Homework Statement I have been wondering about temperature and it's relation to kinetic energy I didn't study thermodynamics so I hope that replies could be simplified.I am trying to think about the perfect gas law to relate kinetic energy per molecule to temperature, and I want to know if I...

Homework Statement From the average separation between air molecules at STP, and their mean speed, estimate how long it would take one molecule to move into the region occupied by another. Assume that air consists mainly of nitrogen molecules. Homework Equations 1/2mv^2 = 3/2KT...

Hi, I'm doing some calculations on fluorescence and I'm a little stuck on statistics. Let's say I need to measure 20 seconds to collect 10000 photons from a single molecule. Then I can say well I want to measure at most 1 second and therefore I need 20 molecules in order to collect 10000...

You can obtain a rough estimate of the size of a molecule with the following simple experiment: Let a droplet of oil spread out on a fairly large but smooth water surface. The resulting ”oil slick” that forms on the surface of the water will be approximately one molecule thick. Given an oil...

The Hamiltonian of the diatomic molecule is given by H = p1^2 / 2m + p2^2 / 2m + 1/2 k R^2, where R equals the distance between atoms. Using this result, given in standard texbooks, I keep geting C = 9/2 kT instead of 7/2 kT for heat capacity. I've traced down my problem to the potential energy...

Hi there, I'm trying to reconstruct the ESP charges that have been determined in a paper using a Gaussian-like quantum chemistry program. While I understand the basic notion of the iterative procedures to approximate the wavefunctions etc., I'm not a chemist and so I'm having problems with...

Homework Statement 20. If the central N in the NH3 molecule did not use sp3 hybridized orbitals. What would be the expected angle in NH3? Homework Equations The Attempt at a Solution I should just consider 3 of the H: 1s^{1} bonding with the P_{x} , P_{y} , P_{z} respectively and the angle is...

Homework Statement ...Suppose an oxygen molecule (m=5.32E-26 kg) traveling at this speed (\nu_{rms}=484 m/s) bounces back and forth between opposite sides of a cubical vessel 0.10 m on a side. What is the average force the molecule exerts on one of the walls of the container? (Assume that the...

1. The average translational kinetic energy of a nitrogen molecule at temperature is _____ check picture 2. 3. The Attempt at a Solution : since nitrogen is diatomic then it has 5 degrees of freedom and therefore the average kinetic energy wouldn't be 3/2kt it would...

Homework Statement Gas is contained in an enclosure in which one of the walls is a plane of area A. The wall acts as a frictionless piston, moving with constant velocity u in the positive x-direction, thus increasing the volume V of gas enclosed. A gas molecule of mass m approaches the...

Hello, I am new in computational chemistry. I was calculating by "Moller Plesset Second Order perturbation theory -MP2-" (using GAMESS) molecular parameters of Cs3Cl2-. Among them i found two complex frequencies of vibration. My question is now, what is the physical meaning of those complex...

Why is the positive charge of the NAD+ molecule located on the nitrogen in the nicotinamide group? This nitrogen has 4 bonds attached to it, but nitrogen only has 3 holes in its valence shell, so wouldn't this make a negative charge on this nitrogen?

I am wandering whether this can happen? When a molecule shares 4 pairs of bonded electons? Say like a C2 Molecule?? maybe. Could it happen or does it happen??

Homework Statement For l=1 the angular momentum components can be represented by the matrices: \hat{L_{x}} = \hbar \left[ \begin{array}{ccc} 0 & \sqrt{\frac{1}{2}} & 0 \\ \sqrt{\frac{1}{2}} & 0 & \sqrt{\frac{1}{2}} \\ 0 & \sqrt{\frac{1}{2}} & 0 \end{array} \right] \hat{L_{y}} =...

How do you use the C_ij matrix to find the harmonic frequency (or frequencies) of a diatomic molecule, the OH (hydroxyl) radical? (I have no idea how to set it up for this.) This is from Feynmann's book on Statistical Mechanics...

Hi all. I love the fact that you have this forum! I need help with a problem of mine that has been lingering in the back of my mind for years. I would like to put it to rest. I am a backyard hands on kind a guy with regards to Physics. My background is in Mechanical Engineering but I have...