In: Chemistry
The bond disssociation of O2 is 498kJ/mol (i.e., it requires 498 kJ to take one mole of O2 molecules and break the bonds to make two moles of O atoms). What wavelength photon, in nm, would posess the minimum energy to break one O2 molecule into two O atoms?
energy require to dissociate 1 mole of O2 = 498 KJ = 498000 J
1 mole contain 6.022 1023 molecule hence, to dissociate 6.022 1023 molecule require energy = 498000 J
then to break 1 molecule of O2 require energy = 1 498000 / 6.022 1023 = 8.269678 10-19 J
we know equation
E = hc / where,
E = energy of photon required = 8.269678 10-19 J
h = Planck constant = 6.62610-34J s
c = velocity of light = 3.00108 m/s
= wavelength in meter = ?
we can wright above equation
= hc/E
Substitute value
= (6.62610-34)(3.00108) / (8.269678 10-19)
= 2.4037212 10-7 m
1m = 1 109 nm
then 2.4037212 10-7 m = 240.37 nm
240.37 nm wavelength of photon required to break one O2 molecule in two O atom