Oxygen (8)
- Oxygen is the most abundant chemical element by mass in the Earth’s biosphere, air, sea and land.
- Oxygen constitutes 49.2% of the Earth’s crust by mass.
- Oxygen gas is the second most common component of the Earth’s atmosphere, taking up 20.8% of its volume and 23.1% of its mass.
- Highly reactive non-metallic element and oxidizing agent that readily forms compounds (notably oxides) with most elements.
- At standard temperature and pressure, oxygen is colorless, odorless gas with thermolecular formula O2.
- Liquid oxygen is attracted to a magnet to a sufficient extent that a bridge of liquid oxygen may be supported against its own weight between the poles of powerful magnet.
- A metallic phase was discovered when oxygen is subjected to a pressure of above 96 GPa.
- The solubility of oxygen in water is temperature-dependent, and about twice as much (14.6mg/L) dissolves at O°C than at 20°C (7.6mg/L)
- Oxygen condenses at -182.95°C or liquefies at -185°C and freezes at -218.79°C.
- Three stable isotopes: O-16, O-17, O-18, with O-6 being the most abundant (99.762% natural abundance).
- Photosynthesis:
- Oxygen is used medically for patients who require mechanical ventilation, often at concentrations above the 21% found in air.
- The air is liquefied at -200°C.
CO2 + H2O + Sun Light (Photons) → Glucose (C2H12O6) + DiOxygen (O2)