Oxygen

## General Information (more on wikipidia)

 Molecular Weight (g/mol) Density (g/L) Radius (m) Reference Species O2 32 D R [1]

In science, oxygen is a chemical element with the chemical symbol O and atomic number 8. The word oxygen derives from two roots in Greek, οξύς (oxys) (acid, lit. sharp) and -γενής (-genēs) (producer, lit. begetter). It was recognized in 1777 by Antoine Lavoisier, who coined the name oxygen from the Greek roots mentioned above because he erroneously thought that it was a constituent of all acids. (The definition of acid has since been revised). Oxygen has a valency of 2. On Earth it is usually bonded to other elements covalently or ionically.
Diatomic oxygen (O2) is one of the two major components of air (20.95%). It is produced by plants during photosynthesis, and is necessary for aerobic respiration in animals. It is toxic to obligate anaerobic organisms and was a poisonous waste product for early life on Earth.

## Diffusion of Oxygen in water:

• Alone at 25 degrees: $D = 2000\ \mu m^{2} s^{-1}$ [1]
• Alone at 25 degrees: $D = 2000\ \mu m^{2} s^{-1}$ [2]
• Dependence on temperature [3]:
 Temperature Viscosity of H2O [centipoises] O2 Diffusion Coefficient [$\mu m^{2}$/s] 20 C 1.002 1970 40 C 0.653 3240 50 C 0.547 3990 60 C 0.467 4820

## Diffusion of Oxygen in cytoplasm

Bibliography
1. J. Crank, "The Mathematics of Diffusion" (Oxford University Press, 1956; 2nd ed. 1976)
2. Han, P., and D. M. Bartels. 1996. Temperature dependence of oxygen diffusion in H2O and D2O. J. Phys. Chem. 100:5597-5602.