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Water is ~11% hydrogen by mass but ~67% hydrogen by atomic percent, and these numbers along with the complementary % numbers for oxygen in water, are the largest contributors to overall mass and atomic composition figures. Because of water content, the human body contains more oxygen by mass than any other element, but more hydrogen by atom ...
In lean healthy adult men, the total body water is about 60% (60–67%) of the total body weight; it is usually slightly lower in women (52–55%). [2] [3] The exact percentage of fluid relative to body weight is inversely proportional to the percentage of body fat. A lean 70 kg (150 lb) man, for example, has about 42 (42–47) liters of water ...
Metabolic water refers to water created inside a living organism through metabolism, by oxidizing energy-containing substances in food and adipose tissue. Animal metabolism produces about 107–110 grams of water per 100 grams of fat , [ 1 ] 41–42 grams of water per 100 g of protein , and 60 grams of water per 100 g of carbohydrate .
2 units, i.e., at intervals of 3 carbon atoms along the chain. For instance, α-linolenic acid is an 18:3 fatty acid and its three double bonds are located at positions Δ 9, Δ 12, and Δ 15. This notation can be ambiguous, as some different fatty acids can have the same C:D numbers.
Heat is lost from the body in proportion to the amount of exposed skin. [289] [290] The head accounts for around 7–9% of the body's surface, and studies have shown that having one's head submerged in cold water only causes a person to lose 10% more heat overall. [291] [medical citation needed]
Water is amphoteric: it has the ability to act as either an acid or a base in chemical reactions. [87] According to the Brønsted-Lowry definition, an acid is a proton (H +) donor and a base is a proton acceptor. [88] When reacting with a stronger acid, water acts as a base; when reacting with a stronger base, it acts as an acid. [88]
The tears are unique among body fluids in that they are exposed to the environment. Much like other body fluids, tear fluid is kept in a tight pH range using the bicarbonate buffer system. [15] The pH of tears shift throughout a waking day, rising "about 0.013 pH units/hour" until a prolonged closed-eye period causes the pH to fall again. [15]
Water is an inorganic compound with the chemical formula H 2 O.It is a transparent, tasteless, odorless, [c] and nearly colorless chemical substance.It is the main constituent of Earth's hydrosphere and the fluids of all known living organisms (in which it acts as a solvent [20]).