Potential Energy between molecules

  • Thread starter Pi Face
  • Start date
  • #1
76
0

Homework Statement


The two sides of the DNA double helix are connected by pairs of bases (adenine, thymine, cytosine, and guanine). Because of the geometric shape of these molecules, adenine bonds with thymine and cytosine bonds with guanine. The figure shows the thymine–adenine bond. Each charge shown is +/- e and the H-N distance is 0.110 nm.

http://imageshack.us/photo/my-images/41/236ir.jpg/

1)
Calculate the electric potential energy of the adenine–thymine bond. To keep the calculations fairly simple, yet reasonable, consider only the electric field due to the and the combinations, assuming that these two combinations are parallel to each other. Remember, however, that in the set, the exerts a force on both the and the and likewise along the set.

2)
Compare this energy with the potential energy of the proton–electron pair in the hydrogen atom. The electron in the hydrogen atom is 0.0529 from the proton.


Homework Equations





The Attempt at a Solution


So for part 1, U=kq1q2/r

But what do I take the potential energy of? Every combination of the 6 charges? How do I know what r is in between the OHN and NHN? I know the distances between charges for each charge in OHN, and for each charge in NHN, but not between the two.

For part 2, I have less of a clue because it requires using the answer to part 1 (answer to part 1 divided by U_hydrogen)

So for the potential energy of hydrogen, I assume I use +q and -q as the two charges, and 0.0529nm as r?

I've already done all the other HW problems because they were straightforward, but when they throw chemistry into the mix I get confused...

Homework Statement





Homework Equations





The Attempt at a Solution

 

Answers and Replies

  • #2
76
0
Does anyone even have an idea of how I could approach this problem? If i was simply dealing with a system of 3 charges on a line, would I find the potential energy by adding the 3 possible potential energies together? (kq1q2/r, kq1q3/r, kq2q3/r)?
 
  • #3
76
0
bump =(
 

Related Threads on Potential Energy between molecules

  • Last Post
Replies
5
Views
4K
  • Last Post
Replies
1
Views
2K
Replies
3
Views
1K
Replies
0
Views
972
Replies
0
Views
2K
  • Last Post
Replies
10
Views
7K
  • Last Post
Replies
5
Views
5K
  • Last Post
Replies
12
Views
9K
Replies
1
Views
504
Top