Molecules Definition and 561 Threads

Hi, so glad to be here. This is my first posting. I'm just a 61 year-old dummy, so please help! If a rubber ball is dropped to a hard surface the impact will compress the rubber, storing some of the kinetic energy as potential elastic energy. The rebound will come from this stored potential...

Homework Statement a. On our planet, all air molecules are attracted by gravity. They should all gather closest to the Earth's surface. They don't. Why? b. Draw pictures of molecule distribution in a planet with very low gravity, and one with very high gravity. Homework Equations --...

How many molecules have a white blood cells and red blood cells? What are the chemical description and information about these above molecules?

Hello ! I have a question that breaks the head to me, jejeje In the process of photoemission, the total cross section is defined by: \sigma(\omega) = \frac{4\pi}{3}\alpha a_0^2 \omega \sum_{lmm_\gamma} \left| D_{lmm_\gamma}(\omega)\right|^2 where \alpha is the fine-structure...

CH3CH2CH2CH2OH A benzene ring with an OH group attached on the top and a NO2 group attached at the bottom. A benzene ring with an OH group attached on the top and a CH3 group attached at the bottom. A benzene ring with an OH group attached on the top And my question is, how...

[SOLVED] collisions of molecules.. Homework Statement a 10cm^3 box contains nitrogen at 20degreeC. What is the rate of collisions on one wal of he box. Homework Equations kb=1.38x10^-23 1u=1.661x10^-27 molecular mass of N2=28u avagadros number=6.02x10^23mol^-1 vrms=sqrt((3kbT/m))...

Do the molecules of a gas move randomly when they aren't colliding, or is it only when they have elastic collisions with other molecules? I know it's a retarded question, I don't know much about physics. Also, does the temperature of a body depend on the internal energy of it, or just kinetic...

I have thought of two possible explanations: a) Energy required to break H bonds = Energy released when H bonds form. There is a "constant" equilibrium in the system, meaning, some water molecules form H bonds, releasing energy to the environment which causes other water molecules to loose...

Homework Statement CHCl3 has M= 119 gmol^-1, density (rho) = 1.48 gcm^-3 Find the average separation between molecules in the liquid assuming a simple cubic packing Homework Equations The Attempt at a Solution I have found that there are 7.487x10^21 molecules cm^-3. Each...

Homework Statement At 100 Celcius the rms speed of nitrogen molecules is 576 m/s. Nitrogen at 100 Celcius and a pressure of 2.0 atm is held in a container with a 10cm x 10cm square wall. Homework Equations rate of collisions: N_coll/ \Deltat = (N*A*v_x)/(2V) (this is from my textbook) ideal...

I've been looking into LCD technology recently and have found a ton of sites that explain how twisted nematic crystals guide polarization of incident light and how LCDs work in general. But no one seems to explain which molecules are in fact twisted nematic crystals. can anyone tell me what...

Hey there guys i am new here and not sure if this is in the right section, well here goes. Just doing some revision and realized I must have been asleep for the Kinetic theory lessons, i have now grasped some of the basics, but have come to this question and not usre how to answer it...

Can anyone explain electromerism to me? If possible do mention some links. I've tried Googling it but I couldn't find much.

[SOLVED] reduced mass?! Hi there, I know the reduced mass is defining with the below formula: \frac{1}{\mu} = \frac{1}{m _{1}} + \frac{1}{m_{2}} + ... In Bohr's radius when i want to find the \mu i use the m1 = mass of electron m2 = mass of poroton but what if i need to find...

[SOLVED] average speed Problem: Calculate the average speed of a molecule that strikes a small surface. How does this compare with the average speed of all molecules? I started by using the root mean square speed as the average speed of some random molecule, for example hydrogen. So...

A diatomic molecule XY that contains a polar bond must be a polar molecule. A triatomic molecule XY2 that contains a polar bond does not necessarily form a polar molecule. I need some examples of real molecules to help me explain the difference. Thanks

How do you caclulate the average speed of a molecule? Is it the same as the volume? Thank you for your time.

I've lost track of this book. It must be 15 years old by now. But I really want to find it. Too bad I don't even remember what it's called - except that I'm sure it had the name molecules in it. This book was an intro to many of the common molecules we encounter in our lives. It started off...

hello everybody do u know how to find the number of dative bondings in a molecule without drawing lewis structure?please help

I'm not sure this is the right place to post this question but here goes: In feynman vol.1 39-9 there is a situation where two molecules are about to collide in a CM frame, the frame has velocity Vcm and the two molecules have respective velocities v1 and v2, then there is no correlation...

I was wondering if there was a formula for the relationship between the charge of a molecule to its velocity and/or its weight. Time can be incorperated.

Homework Statement If the translationa speed of the water vapor molecules (H2O) in ir is 648 m/s, what is the translational rms speed of the carbon dioxide molecules in the same air? Both gases are at the same tmperature. Homework Equations V^2 = (3kT)/m The Attempt at a Solution...

okay. i have a test in chemistry tomorrow and I've been studying forever but I am really having trouble with some problems on the study guide. for example, one of the problems is 1) consider the reaction Mg(s)+I2(s)---->MgI2(s) Under which of the following reaction conditions...

How many molecules exist in one cubic centimeter of space at a pressure of 10^-15 atm and temperature of 20 degrees C?

What's the average speed of hydrogen molecules at room temperature and how do you figure it out? Is there an equation? thanks

[SOLVED] Rotational Kinetic Energy and distribution of diatomic molecules a) Calculate the total rotational kinetic energy of the molecules in 1.00 mol of a diatomic gas at 300 K. b) Calculate the moment of inertia of an oxygen molecule (O2) for rotation about either the x- or y-axis shown...

Given the following article: http://www.innovations-report.de/html/berichte/studien/bericht-96564.html What are "acidic water molecules"?

Homework Statement what is the difference between a steroid molecule, phopholipid, and fat molecule?Homework Equations discuss the general difference in their structuresThe Attempt at a Solutionphospholipids are asymetrical with a hydrophilic head and a hydrophobic tail and the other two are...

1. The mass of the deuterium molecule D2 is twice the mass of Hydrogen molecule H2. If the vibrational frequency of H2 is 1.35x10^14 Hz, what is the vibrational frequency of D2, assuming the "spring constant" of attracting forces is the same for two species? Answer in unit of Hz. Homework...

Hi. We have done some experiments on stretching of DNA strands. We want to expand our report with some physical modelling but we are having some problems understanding surface tension. We have read some introductive book about fuild dynamics and used wiki a lot but we still have problems...

[SOLVED] thermal physics Homework Statement a) What is the total random kinetic energy of all the molecules in one mole of neon at a temperature of 305 K? I got 3801.83J (b) With what speed would a mole of neon have to move so that the kinetic energy of the mass as a whole would be equal to...

[SOLVED] Translational Kinetic Energy Homework Statement (Q) Find the average translational kinetic energy of nitrogen molecules at 1600K. Homework Equations Translational KE per degree of freedom = 1/2kT. The Attempt at a Solution Since Nitrogen molecules are diatomic, it has 5...

Homework Statement Give the formula of a fluoride molecule that: is octahedral in shape is trigonal bypyramidal in shape is T-shaped ...etc The Attempt at a Solution Ok, I'm not really actually looking for an answer, because I already know the answers are SF6, PF5, and ClF3. And I have...

I am taking a second course in Quantum Mechanics right now, and one thing is bugging me... The wave function gives us the probability distribution of a particle being in some position. But which part of particle is it talking about? The center of the particle? But then how can you give a wave...

Hey, just wondering if i can get some verification with my answers. I need to find the number of molecules from a concentration that is 1.0x10^-22 M of AsCl3 in one mL. I divided my concentration by 1000mL to get it down to a concentration per mL and multiplied by avogrado's number. My...

Homework Statement Beginning Calculations in Physical Chemistry Barry R. Johnson & Stephen K. Scott Calculate the average number of collisions per second between N_{2} and O_{2} molecules in air @ 298K and @ a pressure of 1 X 10^5 in a room of volume V = 100m^3. (Assume air has the...

Not sure if this is the right place for this.The new nanotechology articles are fascinating. They said it is like a switch that is able to turn on and off without altering its shape. I was also reading that they had solved the puzzles of the mobius strip. are these discoveries related...

Hello, Piston question,i need to work out the time when no molecules are left in the gaseous system.. I have worked out the relative velocity..if i multiply that by the mean free path to get the diffusion coefficient am i getting any closer to the answer? I can work out the change in time...

What exactly happens to the gas molecules in an electric arc? Oxygen turns to ozone, methane turns to acetelyene.

Homework Statement A syringe of volume 20 ml has just been used and now lies empty on the doctor's desk. The pressure in the office is 100,000 Pa. Assume that the air is an ideal gas consisting of nitrogen N2 (80%) and oxygen O2 (20%) molecules. k=1.38×10-23 J/K and the molar mass of oxygen is...

Homework Statement In some diatomic molecules, the force each atom exerts on the other can be approximated by F = -C/r2 + D/r3, where r is the atomic separation and C and D are positive constants. Let delta r = r - r0 be a small displacement from equilibrium, where delta r << r0. Show that...

I need to write the lewis structures of two ionic compounds. Can anyone help me out? Thank you. 1) (NH4)2SO3 2) LiBH4

In the 1999 paper published in Nature by Markus Arndt et al entitled "Wave-particle duality of C60 molecules" he states: The fullerenes are of course in this funny state of superposition as they are 'falling'. Couple questions: 1. Is this drop of 0.7 mm identical to what any object...

Homework Statement Does the molecule in the file attached have an enantiomer? Homework Equations The Attempt at a Solution I think I can draw an internal symmetry plane to divide the molecule into 2 equivalent parts, but then again, it doesn't seem quite right to me. Building...

Homework Statement Suppose a closed vessel of volume V contains a mixture of atomic and molecular Oxygen. Will the volume of the vessel occupied by each species be equal to V? I have this doubt because in my book in order to determine the pressure exerted by each species they have taken the...

Hey, I am a gr11 student and I just did a lab, and I do NOT understand a thing. Ok, so I have hydrated Copper (II) sulfate, and basically I heated it up in a test tube in order to make it an anhydrous copper (II) sulfate compound My question is: -Is this a chemical or physical change...

:confused: Current vacuum technology can achieve a pressure of 1 * 10^-10 mm of Hg. At this pressure, and at a temperature of 30.0 C, how many molecules are in 5.00 cm3 ? ok so atomic number of Hg = 80 80 * 1.661 * 10^-27 yields 1.33 * 10 ^-25 which is the mass of one molecule...

I'd really appreciate it if someone could please give me some hints over how to do the following questions as I'm currently really stuck. 8. (a) What is the average velocity of the molecules in a gas? (b) Explain your answer. 9. Two moles of He gas are at a pressure of 105 Pa and...

which has more potential energy, a Br2 molecule or two separate bromine atoms? I put the molecule because the fact that it is both attracted and repelled by the charges increases its potential energy. I just want to confirm if I'm right.

Matter, mass, and molecules. Does all three always exist together no matter how much energy there is? Do molecules exist inside all matter? I think molecules exist in all matter. I have been researching, but have not found anything conclusive. I drew that conclusion long ago in school...