# Homework Help: The spectrum of the blue part in a candle flame

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1. Mar 16, 2015

### Kamakiri

1. The problem statement, all variables and given/known data
In the spectrum of the blue part in a candle flame, there’s a violet emission at 432 nm due to excited CH* molecules (chemiluminescence). Why 432? Why not 400 or 500? There are emissions at 436, 475 and 520 nm too. Why these numbers?

2. The attempt at a solution
Is it because the energies of the photons emitted correspond to these wavelengths, as E = hc/λ?

2. Mar 16, 2015

### Quantum Defect

Why do the Balmer lines in the Hydrogen spectrum have the wavelengths that they have? If you know the answer to that question, you know why CH* emits at the wavelengths that it does.

3. Mar 16, 2015

### Kamakiri

I read about Balmer lines. The H-alpha spectral line of hydrogen gas is red, since the energy of the photons emitted correspond to 656.3 nm, as E = hc/λ. Is that right?

4. Mar 17, 2015

### Quantum Defect

Yes, you can find out the photon energy the way that you cite, but why that wavelength, and not 670 nm? Why are all of these spectral lines discrete? What is it about the energies of atoms and molecules that are so different from what we ar used to for automobiles, cats, and footballs?