Tutorial_Intermolecular_Forces_answer - Tutorial for...

Info icon This preview shows pages 1–2. Sign up to view the full content.

Tutorial for Lecture Intermolecular forces 1. Use this equation for calculating the energy of hydrogen bond formed by protein backbone amide and carbonyl groups ( 1 cal = 4.184 J): q1 and q2 are in unit of e, all the distances are in the unit of Angstrom. The equation of electrostatic or Coulomb potential is 𝐸𝐸 = 1 4 𝜋𝜋𝜀𝜀 0 𝑄𝑄 1 𝑄𝑄 2 𝑅𝑅 = 1 4 𝜋𝜋𝜀𝜀 0 𝑞𝑞 1 𝑞𝑞 2 𝑒𝑒 𝑒𝑒 𝑟𝑟Å = 𝑒𝑒 2 4 𝜋𝜋𝜀𝜀 0 𝑞𝑞 1 𝑞𝑞 2 𝑟𝑟 q1 and q2 are in unit of e and distance in the unit of Angstrom, so we need to get a) How does the constant, 332 kcal/mol come from? b) For C=O group q1=0.42, for NH group q2=0.2. In a typical helical conformation, we measure the following lengths: rNO=2.92Å, rHC’=3.14 Å , rHO=1.97Å , rNC’=4.11Å. What is E in unit of kJ/mol? (-10.5 kJ/mol) 2. Intermolecular interactions are often described by the Lennard-Jones potential which gives the internal energy of interaction between two molecules as a function of intermolecular separation: 1
Image of page 1

Info icon This preview has intentionally blurred sections. Sign up to view the full version.

Image of page 2
This is the end of the preview. Sign up to access the rest of the document.
  • Spring '16
  • Energy, Interactions, Total Energy, Ångström, RNC, Lecture Intermolecular forces