What is the percentage of oxygen found in the atmosphere? Name two compounds of oxygen found in nature. Name any three processes in which oxygen is used up in atmosphere.
20.94% oxygen is found in atmosphere. Diatomic O (oxygen) and triatomic O (ozone) are two compounds of oxygen found in nature.
Processes in which oxygen is used up (i) Respiration in most organisms.
(ii) Combustion of fossil fuels.
(iii) Formation of oxides, e.g. nitrogen oxides during atmospheric fixation of nitrogen.
(iv) Decomposition of organic matter.