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Chemistry Forums for Students => Undergraduate General Chemistry Forum => Topic started by: stev3n on November 06, 2008, 06:20:42 PM

Title: Wavelengths and Energy
Post by: stev3n on November 06, 2008, 06:20:42 PM

If you are bombarded with 1.00 mol of photons with a wavelength of 375nm, what amount of energy, in kilojoules per mole of photons, are you being subjected to?

Am I right? I'm just confused with units.

c=vy (y being lambda, wavelength)
v= c/(375nm/1E-9)
v= 7.97E-4

E=hv
E=5.28E-37

Title: Re: Wavelengths and Energy
Post by: student8607 on November 06, 2008, 07:04:17 PM

I, by far, am a beginner as well but this is what I think...

v = constant / wavelength
(3.00x10^8m/s) / (375x10^-9nm) = 8.00x10^14s-

E = hv
(6.626x10^-34Js) x (8.00x10^14s-)
5.3x10^-19J

Title: Re: Wavelengths and Energy
Post by: stev3n on November 06, 2008, 07:54:41 PM

Thanks, that is right (I messed up on the nm conversion factor), but you still have to multiple by 6.022E23 and then convert J to KJ. thanks!

Title: Re: Wavelengths and Energy
Post by: student8607 on November 06, 2008, 07:59:22 PM

no problem