{[ promptMessage ]}

Bookmark it

{[ promptMessage ]}

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

Info icon This 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
Image of page 1

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

View Full Document Right Arrow Icon
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

{[ snackBarMessage ]}

What students are saying

  • Left Quote Icon

    As a current student on this bumpy collegiate pathway, I stumbled upon Course Hero, where I can find study resources for nearly all my courses, get online help from tutors 24/7, and even share my old projects, papers, and lecture notes with other students.

    Student Picture

    Kiran Temple University Fox School of Business ‘17, Course Hero Intern

  • Left Quote Icon

    I cannot even describe how much Course Hero helped me this summer. It’s truly become something I can always rely on and help me. In the end, I was not only able to survive summer classes, but I was able to thrive thanks to Course Hero.

    Student Picture

    Dana University of Pennsylvania ‘17, Course Hero Intern

  • Left Quote Icon

    The ability to access any university’s resources through Course Hero proved invaluable in my case. I was behind on Tulane coursework and actually used UCLA’s materials to help me move forward and get everything together on time.

    Student Picture

    Jill Tulane University ‘16, Course Hero Intern