Question

An X-ray photon of wavelength 0.920 nm strikes a surface. The emitted electron has a kinetic energy of 936 eV. What is the binding energy of the electron in kJ/mol? [KE = 1/2 mv^2; 1 electron volt (eV) = 1.602 10-19 J]

Answer 1

   hv    = hv0 + KE

   hv = hc/lamda

lamda = 0.92nm   = 0.92*10^-9 m = 9.2*10^-10 m

           = 6.625*10^-34 * 3*10⁸/9.2*10^-10

             = 2.16*10^-16 J

KE       = 936ev = 936*1.602*10^-19 J

                           = 1.5*10^-16 J

hv0    = hv-KE

         = 2.16*10^-16 -1.5*10^-16

         = 6.6*10^-17 J      = 6.6*10^-20 Kj

          = 6.6*10^-20 * 6.023*10²³    = 3.97*10⁴ Kj/mole