Question #db2ec

1 Answer
May 5, 2017

Answer:

The light is not visible.

Explanation:

The difference in energy is

#"(1578 - 1472) kJ/mol" = "106 kJ/mol"#

This corresponds to

#"106 000 J"/(1 color(red)(cancel(color(black)("mol electrons")))) × (1 color(red)(cancel(color(black)("mol electrons"))))/(6.022 × 10^23 color(white)(l)"electrons") = 1.760 × 10^"-19"color(white)(l) "J/electron"#

#E = hf = (hc)/λ#

#λ = (hc)/E = (6.626 × 10^"-34" color(red)(cancel(color(black)("J·s"))) × 2.998 × 10^8 "m"·color(red)(cancel(color(black)("s"^"-1"))))/(1.760 × 10^"-19" color(red)(cancel(color(black)("J"))))#

#= 1.13 × 10^"-6" color(red)(cancel(color(black)("m"))) × (10^9 color(white)(l)"nm")/(1 color(red)(cancel(color(black)("m")))) = "1130 nm"#

This wavelength is outside the visible region.