Given that diatomic chlorine is the most stable form of the element, and that the ΔHf° value for atomic chlorine is +121.7 kJ/mol, calculate the maximum wavelength that can dissociate diatomic chlorine into monoatomic chlorine. What type of radiation (UV-A, UV-B, UV-C) does this wavelength correspond to?

The maximum wavelength of light that can dissociate diatomic chlorine into the monatomic chlorine form is 984 nm.

Explanation:

Given: ΔHf° value for atomic chlorine is +121.7 kJ/mol

1 Step

Converting kJ/mol into kJ (knowing that in 1 mol there is 6.023*10^23 molecules)  

ΔHf° in kJ = 121.7 kJ/mol* 1 mole / 6.023*10^23

ΔHf° = 2.02*10^-22 kJ

ΔHf° = E = 2.02*10^-19 J

2 Step

Converting ΔHf° to a wavelength:

knowing the E = h*C/У

h = 6.626 x 10^-34 J·s

C = 3.00 x 10^8 m/s

У = h*C/E = (6.63 x 10^-34 J·s)(3.00 x 108 m/s) / 2.02*10^-19 J

У = 9.84*10^-7 m = 984 nm

3 Step (What type of radiation?)

UV-A wavelength range = 315 nm to 400 nm

UV-B wavelength range = 280 nm to 315 nm

UV-C wavelength range = 100 nm to 280 nm

This wavelength is not corresponding to any of the wavelength range (UV-A, UV-B, UV-C).

these nuts

it can be observed without changing the identity of the object.

it depends on what substance you're talking about as well as many other factors. in quantum mechanics, the observation of particles affects the observers ability to measure certain properties. for example: you can know the velocity of a particle, but you can't know it's position; or you can know it's position, but not it's velocity. it's like trying to find out where a grain of sand is by throwing other grains of sand at it. once you find out where it is, it's been moved. it's also like trying to find an answer to the question of whether or not a tree falling in a forest makes a sound if nobody is there to hear it. paradoxically, the only way to find out is to be there and hear it.