posted by lola on .
What is the spectra/spectrum (?) of the following gases?
I'm not understanding this chapter really well. I have to research this stuff online but I don't really understand what I'm supposed to be looking for.
The spectrum of an element consists of a series of wavelengths (colors in the visible spectrum but there are wavelengths in the ultraviolet and infrared regions, also) that are emitted by the excited atom(s) of the element. In practice, the wavelengths are sent through an instrument, usually a spectrograph, that separates the wavelengths from each other. A photograph can be taken and the wavelength of each color can be measured. Identification of the wavelengths allows one to compare with known spectra and identify the element. What you need to find on the Internet is a spectrum of each of the elements in the question. He, H2, N2, and Ne are gases and the spectrum of each is relatively simple. This sites may help for hydrogen. I obtained it by going to www.google.com and typing in spectrum hydrogen picture.
Thank you! But would I use emission or absorption?
The problem you posted doesn't say. If the original problem (the one from which you obtained your question) doesn't say, it doesn't matter. The only difference is that the emission spectrum is a photograph (negative) of dark lines against a white background. The absorption spectrum is a photograph (negative) of white lines against a black background. The wavelength of the black line of the emission spectrum is the same as the white line of the absorption spectrum.