By what means is composition of totally unknown liquid determined?
In: Chemistry
Usually by spectroscopy. There are different types of spectroscopy, each revealing a different aspect of the compound. NMR Spectroscopy works by putting a sample in a very strong magnetic field and irradiating it with radio waves. At some frequencies, the atoms absorb the radio waves, and from these frequencies you can work out the structure of the molecule (the same principle is used in MRI). Other types of spectroscopy, like IR and UV/VIS spectroscopy, measure the absorbtion of infrared/UV/visible light by the compound, which can act as a “fingerprint” of the molecule. Mass spectrometry determines the mass of the compound by ionizing it (charging the molecule) and shooting a beam of the ionized sample along a magnet. The magnet repels the charged molecules, and the degree of repulsion can be measured, which depends on the mass of the molecule.
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