Question

What is the wavelength (in nm) of radiation that has an energy content of 7.67 x 10^3 kJ/mol?
I got myself confused on how to set it up.

Answer 1

you have to get the value in energy terms (per photon, not per mole of photons)

Answer 2

How do you set that up? Do you use the E = hv formula?

Answer 3

yeah, but you need to divide by avogadro's number first

Answer 4

For which part?

Answer 5

\[\frac{ 7.67 \times 10^3 kJ }{ mol } \times \frac{ 1000J }{ 1kJ } \times \frac{ 1mol }{6.022 \times 10^{23}photons }\]. You would use this dimensional analysis to find energy per photon (J/photon).

This would be E

Next use
E=hv
h is a Planck constant
Find v which is frequency

Then use
\[c=\lambda v\]
where c is speed of light. It has a constant of 3.00 x 10^8m/s
You are to find lambda which is wavelength.
It would be in meters.
1m=1.0 x 10^9nm

Good luck solving it.

Answer 6

1.56 x 10^11. Would that be right?

Answer 7

You mean 1.56 x 10^1
Because thats what I got.

Answer 8

Yeah. Meant that.

Answer 9

How do you tell where it is on the electromagnetic spectrum?

Answer 10

Alright. Thank you.

Answer 11

You write the answer in meters

Then you would use this chart.


http://www2.lbl.gov/MicroWorlds/ALSTool/EMSpec/EMSpec2.html

Answer 12

No problem!
It can be challenging at first.
Good luck on your work.

Answer 13

Thanks!