4) A general intermolecular pair potential is given by:
w(r) = A/r12 – B/r6 = 4ε[(σ/r)12 – (σ/r)6]
a) What is the potential energy at r = σ
b) In terms of σ, where does the minimum energy occur?
c) What is the minimum energy (in terms of ε)?
d) At the minimum energy, what is the van der Waals contribution?
4) A general intermolecular pair potential is given by: w(r) = A/r12 – B/r6 = 4ε[(σ/r)12...
14-5. Using Eqs. (14-14) and (14-17), calculate the van der Waals constants a and b for nitrogen. For u(r), assume a Lennard-Jones 6-12 potential with ε and σ given in Table 12-3. Compare these calculated values to the experimentally determined values, a 1.39 x 106 cm atm/mole and b-39.1 cm/mole. Such poor agreement is quite typical, simply indi- cating the inadequacy of the van der Waals equation. 14-2 THE VAN DER WAALS EQUATION We start with Eq. (14-3), and take...
The potential energy of two atoms in a diatomic molecule is approximated by U(r)=d/r12-b/r6, where r is the spacing between atoms and a and b are positive constants. Find the force F(r) on one atom as a function of r. Find the equilibrium distance between the two atoms. Express your answer in terms of the variables a and b. Is this equilibrium stable? Suppose the distance between the two atoms is equal to the equilibrium distance found in part (b)....
12 R Consider the van der Waals potential U(r) used to model the potential energy function of two molecules, where the minimum potential is at - 2 Ro. Find the force as a function of r. (Use any variable or symbol stated above as necessary.) r = F(r = n(n 1)(n 2)3 n(n 1) Consider a small displacement r R + r' and use the binomial theorem, (1 + x)" = 1 + nx + , to show that the...
4. Estimate the density of methane. The intermolecular potential of methane is given by with a = 2.05482x 10-21 J, σ = 3.786 A, and r is the distance between molecules (in A) a. Make plot of the potential in the range r = 3 A to 10 A. b. Calculate the distance rmin (in A) where the potential has a minimum. c. Estimate the density of liquid methane based on this potential. Find the density of liquid methane in...
4) For Ne, the parameters of the Lennard-Jones 6-12 potential are ε/Kg-35.6 K and σ-275 pm. Plot V(r) in J/mol versus r from 250-800 pm. Calculate the distance rm where dV/dr-0.
Answer at least 7 of the following questions:
a) Describe the weak intermolecular forces (charge-charge, H-bond, van der Waals, & Hydrophobic force etc). b) Describe the structural properties of the peptide bond, a-helix, B-turn, B -sheet and random coil. c) Describe the structural hierarchy of a protein (1°, 2°, 3° & 4) using examples of globular proteins d) Describe how BME or DTT affects disulfide linkages connecting dimeric and multimeric proteins e) Describe Kd, Km and Vmax of an enzyme...
The potential energy of two atoms in a diatomic molecule is approximated by U(r)=a/r^12−b/r^6, where r is the spacing between atoms and a and b are positive constants. Find the component of force along the line connecting the two atoms, Fr(r), on one atom as a function of r. Find the equilibrium distance between the two atoms. Is this equilibrium stable? Suppose the distance between the two atoms is equal to the equilibrium distance found in part A. What minimum...
The total potential energy describing the NaCl lattice is given by: Utot = [ ( -(αe^2) / (4πε 0r) ) + ( A / r^8 ) ], where a is the Madelung constant (a=1.75 for NaCl) and A is a positive constant. 1. What is the physical meaning of the two terms of Utot? Let r0 be the value of the ionic separation r for which Utot is minimum. 2. Deduce an expression of A as a function of r0....
INTERMOLECULAR FORCES INTRODUCTION LEARNING OBJECTIVES To relate the effecet of intermolecular forces on relative melting points and vapour pressures of some organic substances THEORY Weak attractive forces that occur between individual molecules in substances are called intermolecular forces. These include London dispersion forces, dipole-dipole forces and hydrogen-bonding forces. Collectively, the three types of intermolecular forces are referred to as Van der Waals forces. These attractive forces are much weaker than the chemical bonds between atoms in a molecule. Note that...
(16 pts total) The potential at the surface of a sphere of radius R is given by Vo k(35cos 0-30cos +5cos+3) where k is a constant. Assume there is no charge inside or outside the sphere. 2. a. (5 pts) Write Vo in terms of Legendre polynomials b. (6 pts) Determine the boundary conditions and find the potential inside and outside the sphere. (5 pts) Find the surface charge density σ(θ) at the surface of the sphere. C.