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Chemistry Forums for Students => Undergraduate General Chemistry Forum => Topic started by: akxt on March 06, 2009, 01:14:21 AM

Title: Wavelength and Energy
Post by: akxt on March 06, 2009, 01:14:21 AM

What is the difference in energy between the two levels responsible for the violet emission line of the calcium atom at 422.7nm?

So I have the equation 1/lamda = (RH/hc)x(1/nf^2 - 1/ni^2)

I set the lamda = 4.227 x 10^-7 m, plugged in the constants Rh, h, c to get the change in E. Isn't this what the question is asking? After I calculated it, I checked the answer in the back and mine was way off. The book answer says 4.699 x 10^-19 J.

Any helps are appreciated, thanks

Title: Re: Wavelength and Energy
Post by: ARGOS++ on March 06, 2009, 02:27:57 AM

Dear akxt;

Please show us your work so we can guide you in the direction.
I don’t know how you determined n_i and n_f, and if it can be done with Rydberg formula.

I got the result with the formula:     ∆E = hv   and    v = c/λ.
Or use the formula under the question: "Why Einstein meets Beer-Lambert" on:

"Spectroscopy FAQ (http://www.p-forster.com/english/themes/Spectroscopy/Spectroscopy_FAQ.htm)"

I hope to have been of help to you.
Good Luck!
                    ARGOS⁺⁺