| Description |
Present as 4 allotropes. Used as coke (steel making), carbon black (printing), and activated
charcoal (sugar refining, etc.). The radioactive isotope, C14,
is produced in the atmosphere by cosmic ray bombardment of N14
and is not found in carbon-bearing minerals derived from atmospheric CO2
older than 70,000 years. Diagnostic tests:
As the carbonate (CO32-), effloresces in dilute HCl with the
evolution of colorless and odorless CO2 gas.
As the hydrocarbon, burns in air or O2.
As the element, carbon can be identified from physical properties (diamond,
graphite). You can burn a diamond or
graphite with difficulty by heating it to red heat in an O2
atmosphere where it will leave none or very little residue.
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