What is the energy of a photon with a wavelength of 260 nm. Report your answers to three significant digits.

460.458KJ/mol

Explanation:

The energy of a photon = hv = hc/ f

given wavelength = 260nm

changing nm to m becomes 260 x 10^-9m

remembering that frequency = speed of light(c)/ f wavelength

= 3 x10 ^8 / 260 x10^-9 = 1.15 x 10^15 s-1

frequency (v) = 1.15 x 10^15 s-1

Energy = hv

where h is planks constant =  6.626 X 10^-34 J⋅s

v is frequency = 1.1538 x 10^15s-1

E=  6.626X 10^-34  J⋅s X  1.15 x 10^15s-1 =7.645X 10^-19 joules

But I  mole = 6.023 X10^23

therefore Energy = 7.645X 10^-19 x 6.023 X 10^23 =460,458.35Joules / mole

460,458.35Joules / mole  To  kilojoules/mol = 460,458.35Joules / mole/1000= 460.458KJ/mol

the correct option is c.

isotopes refers to different forms of the same element with the same atomic number but different mass number as a result of difference in their neutron numbers. isotopes have different relative atomic mass but share the same chemical properties.