Question

1. How we can determine Na concentration in solution (what is the relationship

between # of photons emitted vs. concentration)?

2. •Explain energy diagram of Na in room temperature and what happens if atoms are subjected to high temperature (2000K).

3. How I calculate RSD% ?

Answer 1

1) Flame photometry is also known as atomic emission spectrometry.It works on the basis of heating the metal, in this case sodium, such that the atoms of the metal travel from ground state to their excited state.The atoms then return to their ground state and release their energy as photons of ultraviolet radiation.The wavelength of the UV radiation is then measured.Relative precision and accuracy can be expected to be between ±1?5% because of the characteristic emission lines from the gas?phase atoms in the flame plasma, which eliminates interferences from most other elements.Since there are many experimental variables affecting the intensity of the light emitted from the flame, the result must be calibrated.The apparatus used for this experiment is a Coleman Flame Photometer, Model 21 with a total consumption burner using natural gas and oxygen.

A sample interference filter is used to isolate the wavelengths, ?.  The light from the flame is then transmitted into a photodiode in the small electronics box by way of a fiber optic cable.  The electronics within the electronics box convert the output from the photodiode into a digital display.  The steps that the metal, in this case sodium, actually goes through for this procedure is as follows: