The energy required to break one mole of Cl - Cl bond is "242 kJ/mol". What is the longest wavelength of light capable of breaking a single Cl - Cl bond? (take c = 3 xx 10^8 "m/s" and N = 6.022 xx 10^23 "mol"^(-1))

1 Answer

sf(495color(white)(x)nm)

Explanation:

sf(Cl_2rarr2Cl*)

sf(DeltaH=+242color(white)(x)"kJ/mol")

I will work out the energy required to dissociate 1 molecule of sf(Cl_2):

sf(E=(242xx10^(3))/(6.022xx10^(23))=4.0186xx10^(-19)color(white)(x)J)

Now I use the Planck Expression:

sf(E=hf=(hc)/lambda)

:.sf(lambda=(hc)/E)

sf(lambda=(6.63xx10^(-34)xx3xx10^(8))/(4.0186xx10^(-19))color(white)(x)m)

sf(lambda=4.949xx10^(-7)color(white)(x)m)

sf(lambda=495color(white)(x)nm)