Randy Holmes-Farley
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Reef Chemistry Question of the Day #249
Reefers are becoming more and more aware of certain sophisticated instruments for analysis of aquarium water, such as ICP, which stands for inductively coupled plasma. Essentially, the entire sample is sucked into a super hot plasma and every molecule in the sample breaks down into individual atoms at this very high temperature (many thousands of degrees). The elements present are detected in a variety of ways.
One primary way to detect the atoms present is by the wavelengths of light they emit at these temperatures. This process is sometimes abbreviated as OES (optical emission spectroscopy) or AES (atomic emission spectroscopy).
How does the emission tell you which atoms/ions are present?
A. The charge to mass ratio on the ions in the plasma determines the wavelengths emitted, so one can calculate which atoms must be present based on calculating the mass from the wavelength for various potential charges each ion.
B. The rotation frequency of the atoms determines the emission wavelength, and that rotation frequency is determined by the plasma temperature and the mass. So if you know the temperature and the emission wavelength you can calculate the mass of each element present.
C. The emission comes from electrons falling from high energy orbitals to lower energy orbitals in the plasma, so from knowledge of the electron orbital energies of each element, you can determine which atoms must be present.
D. The emission comes from the atoms dropping from higher energy vibrational states to lower energy vibrational energy states. So from knowledge of the potential vibrational energies of each element, you can determine which atoms must be present.
Good luck!
.
Reefers are becoming more and more aware of certain sophisticated instruments for analysis of aquarium water, such as ICP, which stands for inductively coupled plasma. Essentially, the entire sample is sucked into a super hot plasma and every molecule in the sample breaks down into individual atoms at this very high temperature (many thousands of degrees). The elements present are detected in a variety of ways.
One primary way to detect the atoms present is by the wavelengths of light they emit at these temperatures. This process is sometimes abbreviated as OES (optical emission spectroscopy) or AES (atomic emission spectroscopy).
How does the emission tell you which atoms/ions are present?
A. The charge to mass ratio on the ions in the plasma determines the wavelengths emitted, so one can calculate which atoms must be present based on calculating the mass from the wavelength for various potential charges each ion.
B. The rotation frequency of the atoms determines the emission wavelength, and that rotation frequency is determined by the plasma temperature and the mass. So if you know the temperature and the emission wavelength you can calculate the mass of each element present.
C. The emission comes from electrons falling from high energy orbitals to lower energy orbitals in the plasma, so from knowledge of the electron orbital energies of each element, you can determine which atoms must be present.
D. The emission comes from the atoms dropping from higher energy vibrational states to lower energy vibrational energy states. So from knowledge of the potential vibrational energies of each element, you can determine which atoms must be present.
Good luck!
.
