4FeH2(CO3)2 + O2 = Fe2O3. 2Fe(OH)3 + H2O + 8CO2
Acid ferrous carbonate + Oxygen = Iron-rust + Water + Carbon dioxid
(b) In Living Bodies
The most interesting action of oxygen at ordinary temperature, however, is that which takes place in our bodies and the bodies of all other animals.
By the constant action or beating of the heart all the blood in the body is brought to the lungs every two or three minutes. The actual time has not been determined in man. In large arteries the Rate of blood circulation blood flows ten times as fast as in very small ones. The usual time through a capillary is one second. The time has been determined, however, in lower animals. In a horse the blood travels one foot a second in the largest artery. At present the accepted theory is that in the circuit the blood makes throughout the body, it picks up the waste matter Oxidation of waste matter from tissue that has been torn down by work or effort, and brings it to the lungs, where it meets with the oxygen we breathe and is oxidized or burned.
If the body undergoes excessive effort or exercise, it tears down an excessive amount of tissue, and there is created, therefore, an excessive amount of waste or carbon dioxid. Nature very wisely provides for this contingency by increasing the heart action, thereby sending the blood through the body at greater velocity, forcing more blood to the lungs, thus increasing the demand for oxygen, which is expressed by deep and rapid breathing.
Generation of heat and light
When a substance burns it gives off heat, and generally light. The heat is the result of chemical change or combination, and the light is the result of heat. Whenever oxidation takes place, no matter in what form, heat is produced.
Amount of heat determined by amount of oxygen
The amount of heat given off by the combination of a given amount of oxygen with some other substance is always the same. If it takes place at a very high temperature, as in explosives, the heat is all given off at once, but if it takes place more slowly, the heat passes away, and we may not observe it, but careful experiments prove that heat is always present in oxidation, and the amount of heat is always measured by the amount of oxygen.