Question

4. how much energy, in KJ per mole, is released when an electron makes a transition from n=5 to n=2 in an hydrogen atom? is this energy sufficient to break the H-H bond. (436 KJ/mole is needed to break this bond )?

Answer 1

252.459 KJ/mol & no, that is not sufficient to break H-H bond.

Step-by-step explanation:

Calculate wavelength from the equation

`(1)/(\lambda) = Rh((1)/(n_(1)^(2) ) -(1)/(n_(2)^(2) ) )` where n1 = 2 n2 = 5 Rh = 1.097X10^7 m^(-1)

λ = 4.34X10^-7 m

Now calculate E using

`E = (hc)/(\lambda)` where E = Energy h = Plank's constant c = velocity of light (3X10^8 m/s)

E = 4.194X10^-19 J

now to convert Joules to Joule/mol we need to multiply the energy by avogadro's number which is 6.023X10^23

E = 252458.9873 J/mol

Dividing this amount by 1000 would yield energy in KJ/mol

E = 252.46 KJ/mol

252.46<436 KJ/mol

Thus H-H bond can't be broken by this energy