Molecular Definition and 545 Threads

"A compound contains only carbon, hydrogen, and oxygen. Combustion of 10.68 mg of the compound yields 16.01 mg CO2 and 4.37 mg H2O. The molar mass of the compound is 176.1 g/mol. What are the empirical and molecular formulas of the compound." I saw an earlier post but it wasn't solved yet...

Hi, I have a question regarding the contribution of some molecular orbitals (e.g HOMO, LUMO) to the total density of states of a two-probe system. How exactly are the contributions of the MO ( that look similar to the DOS plots ) calculated, do they have something to do with the local...

What happens at a "molecular" level? Supose we titrate Acetic acid with Sodium hydroxide. When acetate ion begins his hydrolyzation? -Immediately after titration begins? or only when all initial acetic acid is ionizaed and titrated?

Homework Statement Show that the molecular speed probability distribution is normalizedHomework Equations Molecular speed probability distribution P(C)dC = 4pi[m/2pikt]3/2exp[-mC2/2kT]C2dC The Attempt at a Solution I have tried many steps but i keep getting stuck. I tried using the same metods...

I have figured this out

Homework Statement The standard Gibb's free energy for the reaction N2+3H2<--->2NH3 is -33.0 KJ at 298 K. Everything is a gas. Calculate Kp for this reaction. Homework Equations I have in my notes that Keq=e^(-Delta G/RT) where R is the constant 0.008314 KJ/K. I also have a formula...

Homework Statement An ideal gas is in a container at temperture 300 degrees. What fraction of its moelcules will have speeds in the range 1.95v and 2.05v where v is the most probable molecular speed? Assume dN is constant in the range around 2v Homework Equations Maxwell velocity...

hi i'm a pharmacy student and need ur help please i have an assignment with the title(diagnosis of viral infections using molecular biology techniques) can u please give me useful websites on the subject thanks a heap :smile:

1. Determine the shapes of Br2 (2 Bromine atoms) and HBr. Which is more polar and why? 2. No equations. 3. Okay, I know that Br2 and HBr molecule shapes are linear (I know how to draw them) but I do not get how to find which one is more polar. :confused:

How do you size a packed column with molecular sieves?:confused: Thanks.

I don't think the problems I'm going to post are very difficult, but I'm totally clueless regarding chemistry, so they're pretty difficult for me ^^;; I also have a lot of questions to ask, so I hope you don't mind my sticking them all into one topic. I'm looking forward to your help. You don't...

I have looked for the answer but I haven't found it. Why does a fluid ends up being pushed upward in the presence of a higher density fluid? How is it explained at the molecular level?

I tried Chimera, but I found it to be too complicated for I need... is there a simpler program out there for simple molecules?

According to molecular orbital theory, which of the following species is the most likely to exist? a) H_{2}^{-2} b) He_{2} c) Li_{2} d) Li_{2}^{-2} e) Be_{2} I think the answer is c), due to it having a bond order of 1, but I just wanted to make sure.

So, I've read that cutting is essentially where the edge of the knife (or whatever cutting instrument) applies enough force to overcome the intermolecular forces in the object. A more dense object will have greater molecular forces, hence more difficult to cut (in the conventional cutting sense...

Hi, I'm having a lot of trouble with the following question. Answer: ([SIZE="4"]σ1s)2 ([SIZE="4"]σ*1s)2 ([SIZE="4"]σ2s)2 ([SIZE="4"]σ*2s)2 ([SIZE="4"]π2py)2 ([SIZE="4"]π2pz)1 If anyone can tell me how to obtain this answer, I would be very happy. Thanks.

Hi guys, I need some help with this question. What features in the molecular structure of a compound affect its solubility and its melting and boiling points. I need to answer this question with several examples and include structural diagrams. Please help

A compound has the empirical formula CNH4. If 0.2 mol of its molecules has the mass 12.0 g, what is the molecular formula?

i have a question. the problem is a compound contains only nitrogen and hydrogen and is 87.4% nitrogen by mass. a gaseous sample of the compound has a density of .977g/L at 710. torr and 100. degree celsius. what is the molecular compound. i have tried it a little by making the mass of...

A physics student measures molecular speeds in a laboratory apparatus and concludes that the distribution of speeds is such that: 10% have a speed of 200 m/s 10% gave a speed of 250m/s 15% have a speed of 500m/s 30% have a speed of 650m/s 20% have a speed of 900m/s 15% have a speed of 1300...

Hey everyone! I was wondering, when orbitals are hybridized, new hybrid Atomic Orbitals (AO) are formed. Now, when these hybrid atomic orbotals bond with another atomic orbitals, are molecular orbitals formed? For example, when 2 Hydrogens bond to form H2, the 1s orbitals overlap to form 2...

What evidence do we have that stars are forming right now? Molecular clouds? why do we know that molecular clouds are where stars form? any other lines of evidence? i know this is a big topic so a few reasons or a good link would be a good start for me to understand this big topic thanks

In a molecular orbital diagram that shows the bonding of two electrons (like a diatomic molecule), there are sigma and pi bonds, and the sigma and pi antibonds. Here is an example: http://www.westga.edu/~chem/courses/chem410/410_09/sld024.htm I don't understand how to determine where to put...

This might belong in Cosmology, but I'd thought I'd start it here. Astronomers Find Molecular Hydrogen At Edge Of Universe http://www.sciencedaily.com/releases/2006/05/060508112217.htm Well OK, but . . . No $#!t ! Thoughts?

what are the advantages of proteins aggregating together, forming molecular complexes?

what is the molecuar formula of CuSO4•xH2O? would it be CuSO4•5H2O?

I am going through Olivier Kahn's book "Molecular Magnetism". I am stuck on something that seems so simple. On page 10, it is stated that \chi=C\sum_{M_S=-S}^{+S}\frac{{M_S}^2}{2S+1} The book then states that this leads to \chi=\frac{C}{3}S(S+1) I've tried to figure the steps between...

The insecticide deildrin contains carbon, hydrogen, oxygen, and chlorin. 1.5100g sample of this compound is burned to produce 2.0938g CO2 (g) and 0.2855g H2O(g). They're half as many chlorine atoms as carbon atoms in the compound. The molar mass of the dieldrin is 381g/mole. What is the...

How do I determine or predict if a substance is molecular or ionic? PLEASE HELP! Thanks!

i also need help with the following problem: lactic acid (found in sour milk) has an empirical formula HC3H5O3. a 1.0-g sample of lactic acid requires 17.0 mL of 0.65 M NaOH (sodium hydroxide) to reach the end point titration. what is the molecular formula of lactic acid? thanks...

Hey guys, I am having a little problem with a problem I am doing in Physics (thermo chapter). Well, here is the problem: "The mass of the H2 molecule is 3.3e24 g. If 10e23 H2 molecules per second strike 2.0 cm^2 of wall at an angle of 55° with the normal when moving with a speed of 1.7...

I realize that IQ has been discussed on this forum to the nth but I also noticed that most everyone in those threads simply dismissed IQ as some triviality. But neuroscience (Not to be confused with Cognitive science, which is Behavioural Psychology of the mind) and other fields for that matter...

I am looking for some force field parameters for nonbonded forces between atoms. In most molecular modeling programs Lennard-Jones function is used to calculate Van der Waals forces where sigma and epsilon are constant values for a pair of atoms. But i cannot find them anywhere. Or if...

How big would a spherical cloud of molecular nitrogen at a uniformed pressure of 1 atm (1x10^5 Pascal) and a temperature of 300 K have to be for it to collapse under the mutual gravitational attraction of its molecules? i.e., What is the critical radius for Jean's collapse of a nitrogen cloud...

:confused: :redface: Hi got this question with which i need help For 1.0 mol of helium at a temprature 27deg C calculate:- i) the total kinetic energy of molecules, ii) the root mean square speed of the molecules

Hi, I need to calculate and visualize molecular orbitals (HOMOs) of few simple organic molecules (may be using DFT method). The molecules are positivly charged. Can anybody please help me with this calculations?

Hi. I have been trying to find the MO diagram for BrF5 since it is not in my textbook. I have been searching the web, and Google but I haven't been able to find anything, if someone knows of a MO diagram on the web I would be thankful If you would tell me where to find it.

never mind its over ! )

How many elements of unsaturation are implied by the molecular formula C8H10ClNO? Draw Three structure, one containing ether and amine group, one containing amide group, one containing amine and ketone group. I have no clue where to begin and read the chapter. I will be very thankful...

I am a junior at molecular biology and genetics and I plan to apply for grad school next year. So I need to take GRE general and subject tests, plus TOEFL. My main concern is about GRE: when should I start preparing for it? I would really appreciate advices also on how to study. Thanks! Gamze

:confused: HI I need some major help in creating a costume that illustrates a molecule involved in a process, can someone please help me i have to wear the costume in class tomorrow and am not allowed to make a model . I need some ideas as to what process is easy to do and how i can make a...

How would i calculate the weight of a mer, for example a mer of PTFE.

Hi ; Is there anybody using SageMD for molecular experiments. I am planning to set up a mail group for SageMD or all the molecular dynamics simulator software. Please write me if you want to join or if you know any other place for me to find anyone please tell me... Thank you all...

Hi Guys! my question goes like this a 5% solution of urea is isotonics with 0.877% of Solute A. Calculate the relative molecular weight of solute A. now my dear friend, i know its a very simple question but unfortunately, just can't getting any interpretation. I know isotonics sol...

Opinions on this one? Specifically for the QM uninitiated. If you have other recommendations for better clarity, please comment. Thx. A.

I can't figure out the molecular geometry for C2H4Cl2 (dichloroethane). The e- pair geometry seems to be tetrahedral, but I'm not sure for molecular. Any help?

i have been reading articles on molecular assemblies and dna design. my question is: if we take one simple living cell, and using molecular assembly we can create exactly the same copy of that cell (precisely to the atomic level), then will the cell be alive?:bugeye: thanks.

okay here's the equation: In a certain molecular structure, the total energy E between two ions is given by E= (-5.6/r) + 10e^(-r/3) where r is the distance seperating the nuclei. now i already sketched the graph but i don't know how to find the domain of E, or...

Please, can someone answer my question? I know the shape of sp hybrid orbital, but want to know about the others ( sp2,sp3,dsp2,dsp3,d2sp3,d3sp3 ). And are there any other type of molecular orbitals?

Concord Consortium, an educational non-profit, offers a free simulation program called Molecular Workbench, which can be used to learn physics, chemistry and biology through cool simulations. The main page to download the software is: http://workbench.concord.org/modeler/index.html...