Water

Water is an inorganic compound with the chemical formula H2O, a transparent, tasteless, odorless, and nigh-colorless chemical substance, the main constituent of Earth's hydrosphere and known living organisms' fluids acting as solvents.

inoragnic: substances not derived from organisms (metals, non-carbon based compounds; salts, water), often lacking caron-hydrogen bonds
constitiuent: component, element
hydrosphere: Earth's layer like water--on surface (oceans, lakes, etc) in atmosphere (water vapor), and underground (groundwater)
solvent: substance (often liquid) dissolving another substance (the solute) to form a solution
- solute: minor component in a solution, at times dissolved in solvent

As a polar molecule, it undergoes strong intermolecular hydrogen bonding, a big contributor to its physical and chemical properties.

polar molecule: molecule with negative and positive end (like magnets), resulting if molecule's atoms have various elecronegativities (ability to attract electrons), causing uneven charge distribution
- elecronegativities: property of atoms' tendency to attract electrons to itself if forming chemical bonds
intermolecular: existing/undergo among molecules

It is vital for all known life forms, despite not giving food energy/being an organic micronutrient. Due to its presence in all organisms, its chemical stability, its global abundance, and strong polarity relative to its small molecular size; water is often called the "universal solvent".

micronutrient: crucial chemicals needed by organisms in small quantities
relative to: proportional

Since Earth's environment is close to water's triple point, water exists on Earth as solids, liquids, and gases. E.g., Earth's temperatures at 0°C-100°C at the surface lets water to exist as ice, liquid (y0°C and 100°C), and steam (above 100°C) depending on the local conditions.

Another example is the atmospheric pressure at sea level is ~101,325 pascals (1 atmosphere), above the triple point pressure, but still low enough for water to exist in all 3 phases in various environments (e.g., snow, lakes, oceans, and clouds).

triple point: unique temperature combo and pressure at which all phases (solid, liquid, gas) of a substance coexist in equilibrium (e.g., water's temperature is 0.01°C and pressure is 661.657 pascals)

It forms precipitation in rain form and aerosols in fog form. Clouds consist of suspended droplets of water and ice, its solid state. When finely divided, crystalline ice may precipitate in the form of snow. The gaseous state of water is steam or water vapor.

Water covers about 71.0% of the Earth's surface, with seas and oceans making up most of the water volume (about 96.5%).[23] Small portions of water occur as groundwater (1.7%), in the glaciers and the ice caps of Antarctica and Greenland (1.7%), and in the air as vapor, clouds (consisting of ice and liquid water suspended in air), and precipitation (0.001%). Water moves continually through the water cycle of evaporation, transpiration (evapotranspiration), condensation, precipitation, and runoff, usually reaching the sea.

Water plays an important role in the world economy. Approximately 70% of the fresh water used by humans goes to agriculture. Fishing in salt and fresh water bodies has been, and continues to be, a major source of food for many parts of the world, providing 6.5% of global protein. Much of the long-distance trade of commodities (such as oil, natural gas, and manufactured products) is transported by boats through seas, rivers, lakes, and canals. Large quantities of water, ice, and steam are used for cooling and heating in industry and homes. Water is an excellent solvent for a wide variety of substances, both mineral and organic; as such, it is widely used in industrial processes and in cooking and washing. Water, ice, and snow are also central to many sports and other forms of entertainment, such as swimming, pleasure boating, boat racing, surfing, sport fishing, diving, ice skating, snowboarding, and skiing.

Environmental Impacts

History

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Chemical bonds

[2] Water's chemical symbol is H2O, comprised of 2 hydrogen and 1 oxygen atom. Each hydrogen each share an electron to oxygen (covalent bond). As the oxygen atom needs more electron, it's negatively charged and hydrogen atoms are positively charged.

[2]

Due to such polarities, water molecules stick together (hydrogen bonds) as a molecule's positive pole will bond to another one's positive pole.

Properties

[2] A property resulting from such hydrogen bonds is high cohesion for water, causing high surface tension. Water is the most cohesive of all non-metallic liquids. This can be tested by putting water on wax paper/Teflon/something where water beads up (like plant leaves).

cohesion: attraction between 2 things

As water adheres weakly to wax paper but strongly to itself, its molecules hold the droplets togehter in a comnfiguration creating the least surface area. It's such high surface tension that allow some bugs and lizards to run on water.

Water likes to stick on solids like glass (adhesion). Putting water on a glass spreads out as the adhesive force between the water and glasses are higher than the cohesive forces per water molecules in water beads.

adhesion: is attraction between 2 different substances; in this case water and glasses.

[2]

Capillary-driven

[2] Water can defy gravity by capillary action. Due to adhesion, water molecules attract to a straw's molecules. But as the water molecules adhere to it, other molclues are drawn in by cohesion following the molecules, caused by such surface tension till gravity pulls down on the water's weight overpowers the surface tension.

(Fig. 1) [2] Table salt is ionic. Here, it's separated into ions as the poles of water molecules interact to it.

Dissolving

[2] As water is a polar molecule, it's good a good solvent, good at dissolving things (solutes; sugar, etc). It dissolves more substances than any of Earth's liquid, including the strongest acid ever. Solutes likes salt/sugar are hydrophilic as they're polar, with a stronger polarity than water's cohesive forces. If such polar substances are in water, it's strong enough to break all little cohesive forces/hydrogen bonds. I/O hydrogen bonding to each other, water will hydrogen bond around the polar substances.

Hydrophobicity

[2] Hydrophobic occurs if a material/substance can't overcome water's cohesive force.

They lack charged poles, are non polar, don't dissolve in water as they are pushed by water due to its cohesive force . [2.1] They're often made of hydrocarbon don't make hydrogen bonds via water molecules. As it takes more energy for spread on the surface, it coheres to itself into a sphere. If water can't overcome water's cohesive force,

cohere: stick together

Superhydrophobia can occur if. Lotus plants' leaves have water floats on them like liquid mercury.

Density

[2] Water as solids (ices) is the reason why Earth's life is possible. Unlike other solids (which sinks due to being denser than their liquid forms), ice floats in water as it's less dense than their liquid forms.

At ~0°C/32°F, water molecule solidifies and its hydrogen bonds form cristalline structures that space molecules apart more evenly, making ice less dense than water.

If ice was denser than water, it'd sinks in water, then resurface as as ice, and freeze to sink again, and so on. This drastsically shapes aquatic ecosysystems drastically and North Pole.

Heat capacity

[2] Water has very high heat capacity, as it's good to hold heat. This heats heat up and cool down oceans, regulating Earth's temperature and climate. When our body gets hot and swet, heat excites some of the water molecules on skin such that it break the hydrogen bonds and they evaporate, taking the heat energy with them, cooling down the body.

Environmental Impacts

[2.1] E.g., If one stands one a rotating disk with their arm closed/held together, they spin faster. But if they move their body mass out (like extending their arms), it slows down the rotational speed.

It's same case for Earth when (2006) China completed 3 big dams, one of the largest hydroelectric dams ever built, which changed Earth's rotation speed by sending 39 trillion kg water 175 m above sea level. NASA calculates this such water amount cause Earth's rotation to slow down--Each day since have been by 0.6 microseconds.

Hydrophobia in humans [2.1] Hydrophobia can also occur in humans via rabies. One with rabies virus cause severe neurological harm. At late rabies stages, they salivate constantly and their throat and jaw are paralyzed, so their body can't control their mouth's fluid, being in a constant drowning fear.

[3] One can instinctively reject to drink water as if the water can burn him. But vaccination, global rabies threats reduced

History

[2] English Chemist and physicist Henry Cavendish communicated to his servants only via notes added a staircase at the back of his house to avoid contact to them. Some think he was autistic. He was best known as the first to depict hydrogen as a distinct substance water's composition. Most thought in 1700 that water itself is an element. But Cavendish that hydrogen (he claled inflammable air) react to oxygen (called dephlogisticated air) to form water. As he didn't understand what he found as he didn't believe in chemical compounds, he explained his experiments via an element called phlogiston.

[1] (image) [1.1] He used this machine to make oxygen gas.

His work to find the gravity, the comparitive density of hydrogen/other gases by reference to common air. He made an accurate atmosphere's composition. He discovered Earth's density

Environmental Impacts

History

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