discussion key 12.6.11

discussion key 12.6.11 - the expression where n 1,2 is the...

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

View Full Document Right Arrow Icon
Discussion Section Problems 12.6.11 1) To calculate interactions between neutral species (atoms or molecules) you can use the Lennard-Jones equation. Suppose two He atoms interact according to the Lennard Jones equation a )Calculate the potential energy of interaction V(r) if the two He atoms are separated by 2.50x10 -10 m. From the sign of this value for V(r), is the interaction repulsive or attractive? Assume the well depth and Answer: V(r)= 9.94 x 10 -26 J. Because r< σ , V(r)>0 so the interaction is repulsive. b) Repeat the calculation for r=3.50x10 -10 m. Is the interaction attractive or repulsive at this distance? Answer: V(r)= -7.31x10 -26 J. V(r)<0 so interaction is attractive. 2) To calculate interactions between ions in free space (i.e. NOT in solution) you can use
Background image of page 1

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

View Full DocumentRight Arrow Icon
Background image of page 2
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: the expression where n 1,2 is the positive or negative integer charge of the ion, e.g. for Na + interacting with Cl-, n 1 =+1 and n 2 =-1. To do these calculations you need the free space permittivity constant and the unit charge . a) Using your values for and e, calculate . Solution: b) Calculate the Coulombic interaction V(r) between two Ca 2+ ions separated by r=2x10-9 m. Solution: c) Calculate the interaction per mole of Ca 2+ pairs Solution: 3) Using the Table of bond enthalpies provided, calculate the reaction enthalpy for: Note : O 2 is O=O and CO 2 is O=C=O. Bond C-H C-O O=O O-H C=O Enthalpy (kJmol-1 ) 413 358 495 467 799 Solution: Calculate total enthalpy of bonds broken: Now calculate the enthalpy of bonds formed: Final calculation:...
View Full Document

This note was uploaded on 01/18/2012 for the course CHEM 152A taught by Professor Chiu during the Fall '12 term at University of Washington.

Page1 / 2

discussion key 12.6.11 - the expression where n 1,2 is the...

This preview shows document pages 1 - 2. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online