Question

By using photons of specific wavelengths, chemists can dissociate gaseous HI to produce H atoms with certain speeds. When HI dissociates, the H atoms move away rapidly, whereas the heavier I atoms move more slowly.
(a) What is the longest wavelength (in nm) that can dissociate a molecule of HI?

Answer 1

longest wavelength (in nm) that can dissociate a molecule of HI is 4.06 × 10² nm

Since, we have to find out the longest wavelength(in nm) that can dissociate a molecule of HI.

Bond energy of  H-I = 295kJ/mol

Now,

   wavelength can be calculated as ,

λ = $\frac{hc}{E}$

Where h is Plank's constant= 6.626×10⁻³⁴J.s

c is the velocity of light = 3×10⁸ms⁻¹

E is the energy in Joule = 295×10³/6.022×10²³

                                      = 4.89×10⁻¹⁹ J/molecule

now ,

λ = $\frac{(6.626.10^{-34} )(3.10^{8}) }{4.89.10^{-19} }$

   = 4.06 ×10⁻⁷m

   λ = 4.06 × 10² nm

Thus from the above conclusion we can say that, longest wavelength (in nm) that can dissociate a molecule of HI is 4.06 × 10² nm.

Learn more about bond dissociation here:brainly.com/question/2279755

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