Active 5 years, 5 months ago. Dissolved oxygen is vital to life but how does it get there. Consequently, the oxygen content of seawater is 85.7%. Oxygen enters the water through two natural processes: (1) diffusion from the atmosphere and (2) photosynthesis by aquatic plants. There are oxygen atoms in the water molecules, that's why the molecular formula of water is H2O. 1 decade ago. Why are fish able to live underwater? what ion would the oxygen form to dissolve, O- or O2-? There are oxygen atoms in the water molecules, that's why the molecular formula of water is H2O. Gaseous oxygen does not react with water. Do not confuse oxygen atoms with oxygen molecules. It can be found dissolved in water as O 2 molecules. Higher the temperature, lower the solubility of oxygen. 0 $\begingroup$ I know that $\ce{CO_2}$ and $\ce{O_2}$ are slightly soluble in water ($\ce{H_2O}$) In my understanding, when carbon dioxide dissolves in water, it will react to form carbonic acid just like the equation below. DO (dissolved oxygen) is measured in mg/L. Hence to growth and reproduction of aquatic life must have sufficient levels of dissolved oxygen (DO) in the water. Relevance? Dissolved oxygen in water makes aquatic life possible. Answer Save. Because of dissolved oxygen, of course. It is water soluble and functions as an oxidator: O 2 + 2 H 2 O + 4 e--> 4 OH-Oxygen may oxidize organic matter. The mixing of surface waters by wind and waves increases the rate at which oxygen from the air can be dissolved or absorbed into the water.read more Favourite answer. When a liter of water (A) is heated, you will soon have more than a liter of water do to normal expansion (B). Human being takes oxygen from the air with the lungs. Oxygen as well as other gases dissolves in water and its solubility depends on water temperature. Water, as a polar molecule, induces an accumulation of electron density (dipole moment) at one end of non … Freshwater can hold more dissolved oxygen than saltwater because saltwater has less space for oxygen molecules due to the sodium and chloride ions it contains. Gills work better if the water contains more oxygen. Oxygen dissolve in water. Ask Question Asked 5 years, 11 months ago. Warm water holds less dissolved oxygen than cold water because the molecules are moving faster than in cold water and thereby allow oxygen to escape from the water. The mass (weight) of each extra O2 (oxygen) molecule in a liter of water can be added together to get the resulting measurement of DO. 8 Answers. Do not confuse oxygen atoms with oxygen molecules. But dissolving is a physical process, not a chemical process and involved no chemical changes. But dissolving is a physical process, not a chemical process and involved no chemical changes. Lv 4. This is principally a biological process. On the other hand, Fishes take dissolved oxygen through their gills. oxygen is a non polar molecule, o2, how would this dissolve in a polar solvent such as water. In what way and in what form does oxygen react with water? Viewed 738 times 1.