## anonymous one year ago 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.

1. aaronq

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

2. anonymous

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

3. aaronq

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

4. anonymous

For which part?

5. anonymous

$\frac{ 7.67 \times 10^3 kJ }{ mol } \times \frac{ 1000J }{ 1kJ } \times \frac{ 1mol }{6.022 \times 10^{23}photons }$. 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.

6. anonymous

1.56 x 10^11. Would that be right?

7. anonymous

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

8. anonymous

Yeah. Meant that.

9. anonymous

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

10. anonymous

Alright. Thank you.

11. anonymous

You write the answer in meters Then you would use this chart. http://www2.lbl.gov/MicroWorlds/ALSTool/EMSpec/EMSpec2.html

12. anonymous

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

13. anonymous

Thanks!