Chemistry Lab

Emission Spectrum Lab
Name: Yue Wai Ming
IB HL Chem Miss Vick

Aim: The purpose of this exercise is to measure specific atomic emission spectra and to
observe the existence of bright line spectra.

Hypothesis:   Some elements, especially metal compounds usually give off light in a visible spectrum when heated in flame. This heat will cause some of the electrons in the atoms to be excited and the electrons will jump off to higher valence shells. After this happens, the excited electrons will jump back down to their normal shells as they are unstable and return to their ground state. Because of this, it will release the extra energy in a form of radiation of a certain frequency. This causes the release of light. The colour of the flame will depend on the energy needed for the electron to bounce back faster or slower. This light is determined by a spectrometer looking at the emitted photon’s wavelength. My prediction is that the colours the metallic ion produces depend on how far away the wavelength is. The further the wavelength, the darker the colour (darkest being red).

Independent Variable: The type of metal compounds used for heating

Dependent Variable: Measuring the Wavelength of each flame

Controlled Variable: All the metals have to be combined with chloride

Why is has to be controlled:-
There is a reason for using chlorides for all compounds. This is because when we heat up the compounds, the chloride will not interfere with the flame colour as it does not produce its own colour. There are no excited states for chlorine that emit in the visible part of the electromagnetic spectrum.


|Glass Rod                                                                           |Copper Chloride                           |
|Distilled water                                                                     |Lithium Chloride                           |
|Bunsen Burner...