Oxygen

Reactive nonmetalgasblock p

21% of the atmosphere and 46% of the Earth's crust, the oxidant that powers respiration and every fire ever lit.

Atomic number	8
Standard atomic weight	15.999 g/mol ± 0.001
Group · period	16 · 2
Electron configuration	[He] 2s² 2p⁴

About Oxygen

Carl Wilhelm Scheele made oxygen around 1772 and Joseph Priestley independently in 1774, but it was Lavoisier who understood it, killed the phlogiston theory with it, and gave it a name that turned out to be wrong — oxygen means acid-former, and the acid-forming element is really hydrogen. Free O₂ is a biological artefact: cyanobacteria began releasing it about 2.4 billion years ago in the Great Oxidation Event, poisoning most of the existing biosphere and rusting the oceans into the banded iron formations we now mine. Liquid oxygen is pale blue and, unusually for a common molecule, paramagnetic — pour it between the poles of a magnet and it hangs there. Its isotope ratios in ice cores and foraminifera shells are the backbone of the palaeotemperature record.

Use 15.999 g/mol in these solvers

Moles from Mass (n = m/M)

n = \frac{m}{M}

Opens with M = 15.999 g/mol already filled in

Gas Density from Molar Mass

\rho = \frac{PM}{RT}

Opens with M = 15.999 g/mol already filled in

Faraday's Law of Electrolysis (m = QM/nF)

m = \frac{Q M}{n F}

Opens with M = 15.999 g/mol already filled in

Ion Concentration as CaCO₃ Equivalent

C_{\mathrm{CaCO_3}} = C_{\mathrm{ion}} \times \frac{50.04}{\mathrm{EW}}

Opens with EW = 15.999 g/mol already filled in

Acid Feed to Reduce Alkalinity

\dot m = \frac{\Delta \mathrm{Alk} \, Q \times \frac{\mathrm{EW}}{50.04}}{p/100\%}

Opens with EW = 15.999 g/mol already filled in

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