Van der waals Definition and 128 Threads

Homework Statement Express the van der Waals equation of state as a virial expansion in powers of 1/Vm and obtain expressions for B and C in terms of the parameters a and b. The expansion you will need is (1-x)-1 = 1 + x + x2 + ... Measurements on argon gave B = -2.17 cm3 mol-1 and C =...

Homework Statement P = RT/(V-b) - a/V^2 Ive been trying to solve this for V and just can't get it. Homework Equations The Attempt at a Solution IVe gotten to: RTV^2 -aV+ab = P(V^3-V^2b) Any Ideas?

Hello people :), I have a question because I couldn't understand something written in Schwabl's book of Statistical mechanics. Can you please explain why we in the Van der Waals equation of state choose a constant pressure under the critical temperature. I understood the part that we want to...

Homework Statement Homework Equations The Attempt at a Solution I think Graphite is a Van der Waals' Solid and, er, salt would be an ionic. But I really don't have much of a clue about what the second part is going on about! Thanks! :)

Homework Statement The van der Waals potential between two inert atoms is often characterized by the expression: http://bama.ua.edu/~stjones/253hw_files/image025.gif Sketch the function. Expand the potential around the minimum in the form U = U(ro) + ½ k(r-ro)2. Evaluate k in terms of s and...

Homework Statement Express the van der Waals equation of state as a virial expansion in powers of 1/Vm and obtain expressions for B and C in terms of the parameters a and b. (Hint. The expansion you will need is (1–x) -1 = 1+x+x2+... . Series expansions are discussed in Appendix 2 of...

What is the main difference between van der Waals forces and dispersion forces? This statement confuses me: "van der Waals forces are nearly the same thing as dispersion forces." Right now, I have an idea that van der Waals forces includes these attractions: 1. permanent dipole - permanet...

I was looking at the values for the Van der Waals radius on various elements in wikipedia and noticed that Molybdenum does not have one. I searched a bit and found this site http://www.webelements.com/periodicity/van_der_waals_radius/ which lists the elements that have a Van der Waals...

Homework Statement For any Pure Substance, use the relation (1) to show that for a Van der Waals gas, over a range of conditions where c_{v} is effectively constant, that equation (2) gives equations (3) and (4)Homework Equations (1) ~ Tds = du + pdv (2) ~ c_{v}dT + T \frac{\partial...

please explain me importance n role of vanderwaals forces in predicting properties of any molecule

very often, most chemistry books claim that the dominant force helding the molecules together to a certain distance apart is van der Waals' forces, which is a kind of intermolecular forces; However, to investigate the forces microscopically, we found that the force is exactly electrostatic...

are intermolecular an van der waals forces the same thing? I am doing a physics assignment on surface tension and am unsure of what forces are present. i know that there is hydrogen bonding, but what else? thanks

Homework Statement From the van der Waals equation of state, show that the critical temperature and pressure are given by T_{cr} = \frac{8a}{27bR} P_{cr} = \frac{a}{27b^2} Hint: Use the fact that the P versus V curve has an inflection point at the critical point so that the first and second...

Hi, I am looking for table or something that gives a tumb of rule for van der Waals distances - I have some C C spatial interactions which I would like to determine if their interaction contributes to the total energy or should I calculate it with a Lennard-Jones potential to get an...

To Forum Physicists / Administrators... Equations for an ideal gas undergoing an adiabatic process are 3 viz 1) P(v^g)=const 2)T(V^(g-1)) =constant and 3)T(P^((1-g)/g))= constant where g=specific heat for const pressure/specific heat for const volume.These equations suits the Ideal gas...

Homework Statement Calculate the Gibbs free energy for a van der Waals gas (up to an integration constant), assuming a fixed amount of material and temperature. Homework Equations P = \frac{NkT}{V-Nb} - \frac{aN^2}{V^2} dG = -SdT + VdP + udN (where u is the chemical potential) The...

Hello, Can anyone lead me or give me a hint on how to solve this problem? Interaction between neutral atoms and molecules can be decomposed to two different forces: an attractive force at large distances (the Van der Waals force), and a repulsive force at short distances (due to overlap...

How, if you're given a pair of molecules, would you decide which one might have a higher value for a or b? As I understand for instance, a's value will be high if two molecules are attracted to each other and b's value will be high if two molecules strongly repel each other... but how would...

i have to plot isotherms using the van der waals gas theory. i am using Maple to do this but no matter how many different equations i use i cannot get the graphs to look right. it should look like a 1/x curve but with a sharpe trough in it, but all can get is a graph that looks like a normal 1/x...

Could You Explain It To Me In A More Simpler Way That I Can Grasp Thanks

Hi, Consider a pipe with thermally insulated walls. A thermally insulating porous plug in the pipe provides a constriction to the flow of gas. We model this as a sudden jump in pressure. A continuous stream of gas flows from left to right, with the pressure p_1 upstream being larger than the...

For a van der Waals gas experiencing an adiabatic process derive the following expression: T(V-nb)^(R/Cv) = Constant I tried using PV^gamma = Constant with gamma = Cp/Cv and Cp - Cv = nR with PV = nRT but could not get it. Any hints? I would have to use Boyle's law to account for...

The London van der Waals force is approximatly given by F=-c *a^-7 where a is the distance between two neutral atoms and c is something like this: C=-23*hbar*c/4pi*(alpha1*alpha2) where alpha1 and alpha2 =(epsilon-1)/(4pi*N) and N is the atom number density and epsilon the...

the retarded van der waals force is called the casimir force and the diference between them is that in the oscilations in vacumm between to perfect metallics plates if there is a van der waals force virtual photons reach form one plate to the other in casimir the life time of the photon is not...

what's the bonding and forces that exist in a water molecule?is it ionic bond and van der waals force?

Could anyone here say me what's the constants of van der waals for the Sulfur Hexaflouride (SF6)

I've been highly interested in the van der Waals setae adhesive since it was discovered how geckos can stick to walls about three years ago. I have a few questions about it though and I haven't found the answers. What does "directional adhesive" mean? Do geckos have to hang from their toes...

I'm having some problems here... Part of an assignment is to find how density of a gas changes as a function of pressure (1 - 700 atmospheres) using Van der Waals. Unless I've really missed the boat, there is no closed form solution for specific volume in that equation, (p+a/v^2)(v-b)=RT...