Posted by ssss on Thursday, May 30, 2013 at 6:37pm.
The NN bond energy is difficult to measure. Given the values of 190 kJ/mol for the NCl bond energy and 240 kJ/mol for the ClCl bond energy, determine the maximum de Broglie wavelength of an electron capable of breaking the NN bond.
Express your answer in m.

chemistry  bonjo, Thursday, May 30, 2013 at 9:47pm
i guess this is one of the eDX CH3.091 final exam question???

chemistry  Sena, Friday, May 31, 2013 at 4:25pm
Good guess :D

chemistry  Josh, Friday, May 31, 2013 at 4:50pm
Good guess, that's why we need to help each other

chemistry  bonjo, Friday, May 31, 2013 at 9:06pm
ok..how about i do the talking and you do the calculations??..hope this is a best way we help each other, by working together, not just by giving the answer so that others can just jump in and take it without knowing its derivatives..its better to have postings leading to answers...
ok, the question ask for the NN bond. so we need to rearrange the Bond Energy equation BE(NCl) = sqrt[BE(NN) x BE (ClCl)] + 96.3[X(N)X(Cl)^2
rearrange the equation to make BE(NN) the subject.
then we can use the de Broglie equation to find the wavelength..
can anyone try that??...i have 1 more submission left for this question.. 
chemistry  Anony mous, Saturday, June 1, 2013 at 2:16am
what is v value in de Broglie's equation ??

chemistry  Anonymous, Saturday, June 1, 2013 at 4:19pm
But what is X(N) and X(Cl)?

chemistry  bonjo, Saturday, June 1, 2013 at 6:28pm
v is the velocity which can be derived from E=1/2mv^2 (kinetic energy).
the X(N) is the electronegativity for Nitrogen and so as Cl obtained from the periodic table. 
chemistry  Anonyms, Saturday, June 1, 2013 at 11:16pm
Answer plz...

chemistry  nonu, Sunday, June 2, 2013 at 4:34am
still the answer is wrong..............

chemistry  marcia, Sunday, June 2, 2013 at 5:23pm
as bonjo said, let's try to do together
 rearrange the equation to make BE(NN) the subject.
BE(NCl)  96.3[X(N)X(Cl)]^2 = sqrt[BE(NN) x BE (ClCl)]
BE(NCl)  96.3[X(N)X(Cl)]^2 = sqrt[BE(NN) x BE (ClCl)]
(BE(NCl)  96.3[X(N)X(Cl)]^2) / sqrt [BE (ClCl)] = sqrt[BE(NN)]
 Ok, let's put numbers now
(190 kJ/mol  96.3 [3.043.16]) / sqrt [240 kJ/mol]= sqrt[BE(NN)]
(ps. I used Pauling electronegativity values)
190  96.3(0.12)/15.49 = sqrt[BE(NN)]
(190  96.42) / 15.49 = sqrt[BE(NN)]
93.58 / 15.49 = sqrt[BE(NN)]
6.04 = sqrt[BE(NN)]
(6.04)^2 = (sqrt[BE(NN)])^2
36.49 = [BE(NN)]
what's missing?? 
chemistry  marcia, Sunday, June 2, 2013 at 9:17pm
the velocity of the electron is sqrt(2E/m) where E is the bond energy for NN and m is the mass of electron.
So, v = sqrt (2 x 36.49 / 0.000548597 amu)
v = 72.98/0.000548597
v= 133030.25 
chemistry  marcia, Sunday, June 2, 2013 at 9:21pm
now, we use the de Broglie equation to find the wavelength.
Broglie equation: w = h / m v, where w = wavelength; h = Planck's constant in J/s; m = mass in kg; v = speed in m/s. 
chemistry  marcia, Sunday, June 2, 2013 at 9:27pm
w = what we want to know
h = 6.63 x 10^34 J s
m = 9.1 x 10^31 kg (mass of an electron?)
v = I think that I calculete not im m/s 
chemistry  marcia, Sunday, June 2, 2013 at 9:28pm
People, I don't know if I'm in the right way... Could someone HELP too??

chemistry  Anonymous, Monday, June 3, 2013 at 2:18am
marcia, maybe you used kJ instead of j?

chemistry  Anonymous, Monday, June 3, 2013 at 2:19am
and...as the internet says, the bond energy for the NN bond is about 170kj/mol.

chemistry  Pahu, Monday, June 3, 2013 at 6:35am
Solution: 9.8e10 meter
Deatils:
 Calculated NN bond energy: 150.4kJ/mol = 2.507e19J/molecule.
 v electron speed: 7.42e5 m/s
 de Borglie wave lenght = h / (m x v), where h Planc constant, m electron mass, v electron speed 
chemistry  Anonymous, Monday, June 3, 2013 at 7:00am
Thanks a lot, Pahu!