Water

= =



=Water= Water is essential in the daily lives of all living things. Nothing can survive without water. It makes up the majority of the planet we live on, covering 70.9% of Earth's surface, as well as it can be found in just about all living organisms, usually ranging 55-78% of the human body. Water is a substance that can also go under names like:
 * Dihydrogen Oxide
 * Dihydrogen Monoxide
 * Hydrogen Hydroxide
 * Hydronium Hydroxide
 * Hydric Acid

==Structure and Chemical Properties== Water is tasteless, odorless, and nearly colorless. At room temperature, water is a liquid; however, it also is present in nature in solid (ice) and gaseous (water vapor) states. The density of water is 1 g/mL, and water is unique in the way that its volume decreases as the temperature increases.

The chemical formula for water is H 2 O, pointing to the fact that a water molecule is comprised of two @hydrogen atoms and one @oxygen atom. The oxygen atom is covalently bonded to both of the hydrogen atoms, providing the bent shape seen in the accompnying ball-and-stick diagram. The water molecule is a polar molecule, as well, because the oxygen end is slightly negative while the hydrogen ends of the atoms are slightly positive.

Because water has a polar arrangement of atoms, it is an excellent solvent and is often referred to as the universal solvent. This trait further translates into the fact that water rarely occurs in pure form in nature. Many minerals and nutrients often dissolve easily in water. This makes water doubly important to living organisms because water is the substance that often carries the nutrients and minerals most required by living organisms.

At an intermolecular level, water also participates in hydrogen bonding, which is a bond between a hydrogen atom and another electronegative atom such as oxygen, flourine, or @nitrogen. One molecule of water can participate in a hydrogen bond with up to four other molecules, creating a tetrahedral shape. Hydrogen bonding in water helps contribute to the lattice shape in solid water (ice) which helps the ice to have a lower density than its liquid counterpart, further allowing it to float. Hydrogen bonding also leads to water's high boiling point because the hydrogen bonds are difficult to break and necesitate high levels of energy to break them. You should drink a couple of liters of water each and every day.

Water on Earth
Water is the one substance that separates Earth from all other known planets in the universe, and is the substance that makes Earth suitable for life. The earth contains approximately 326 million cubic miles of water, which makes up 70% of the earth's surface. Water is found on earth in all three chemical forms: solid water is found in ice and glaciers; liquid water is found in oceans and lakes; and gaseous water is contained within the atmosphere.

The majority of water on earth can be divided into two broad categories which are fresh water and salt water. Fresh water is contained within lakes, tributaries, ice, and glaciers in Greenland and Antarctica, and in living beings. This variety of water makes up approximately 4.6% of water on earth. The remaining 95% of water on earth is salt water contained in oceans.  The water cycle is also referred to as the hydrologic cycle and is the characterization of the continuous exchange of water on earth. The cycle is made of three phases: evaporation, precipitation, and runoff. The evaporation phase occurs as energy from the sun heats liquid water on Earth's surface, causing it to vaporize from liquid into gas water. The evaporation phase causes water to accumulate in the atmosphere where it condenses around dust, dirt, and pollution particles to form clouds. At this point, given the correct atmospheric conditions, the liquid water in the atmosphere precipitates to the ground in forms such as rain, snow, sleet, or hail Once the water falls to the ground in liquid form, runoff occurs and conditions are ripe for the cycle to start over again.
 * The Water Cycle**

Water is also found in abundance in the atmosphere. As the water cycle delivers water vapor into the atmosphere, it has the potential to contribute to the greenhouse effect as well as form acid rain. Water vapor itself is the most abundant greenhouse in the atmosphere, contributing anywhere from 35% to 66% of the effect. In this capacity, water vapor helps absorb and reflect UV rays from the sun, as well as help trap heat within Earth's atmosphere, helping to maintain temperatures that sustain life.
 * Water in the Atmosphere and Acid Rain**

Water in the atmosphere also has the potential to react with various pollutants and particles in the atmosphere to form acid rain, however. Water reacts with NO x, and SO x to form hydronium ions, nitric acid, and sulfuric acid. More specifically:
 * Sulfurous Acid:
 * 1) SO 2  (g) + H 2 O (l) → H 2 SO 3  (aq)
 * 2) H 2 SO 3  (aq) + H <span style="font-family: Arial,Helvetica,sans-serif; font-size: 90%; vertical-align: sub;">2 <span style="font-family: Arial,Helvetica,sans-serif; font-size: 90%;">O (l) → H <span style="font-family: Arial,Helvetica,sans-serif; font-size: 90%; vertical-align: sub;">3 <span style="font-family: Arial,Helvetica,sans-serif; font-size: 90%;">O <span style="font-family: Arial,Helvetica,sans-serif; font-size: 90%; vertical-align: super;">+ <span style="font-family: Arial,Helvetica,sans-serif; font-size: 90%;"> (aq) + HSO3- (aq)
 * <span style="font-family: Arial,Helvetica,sans-serif; font-size: 90%;">Sulfuric Acid:
 * 1) <span style="font-family: Arial,Helvetica,sans-serif; font-size: 90%;">SO <span style="font-family: Arial,Helvetica,sans-serif; font-size: 90%; vertical-align: sub;">3 <span style="font-family: Arial,Helvetica,sans-serif; font-size: 90%;"> (g) + H <span style="font-family: Arial,Helvetica,sans-serif; font-size: 90%; vertical-align: sub;">2 <span style="font-family: Arial,Helvetica,sans-serif; font-size: 90%;">O (l) → H <span style="font-family: Arial,Helvetica,sans-serif; font-size: 90%; vertical-align: sub;">2 <span style="font-family: Arial,Helvetica,sans-serif; font-size: 90%;">SO <span style="font-family: Arial,Helvetica,sans-serif; font-size: 90%; vertical-align: sub;">4 <span style="font-family: Arial,Helvetica,sans-serif; font-size: 90%;"> (aq)
 * 2) <span style="font-family: Arial,Helvetica,sans-serif; font-size: 90%;">H <span style="font-family: Arial,Helvetica,sans-serif; font-size: 90%; vertical-align: sub;">2 <span style="font-family: Arial,Helvetica,sans-serif; font-size: 90%;">SO <span style="font-family: Arial,Helvetica,sans-serif; font-size: 90%; vertical-align: sub;">4 <span style="font-family: Arial,Helvetica,sans-serif; font-size: 90%;"> (aq) + H <span style="font-family: Arial,Helvetica,sans-serif; font-size: 90%; vertical-align: sub;">2 <span style="font-family: Arial,Helvetica,sans-serif; font-size: 90%;">O (l) → H <span style="font-family: Arial,Helvetica,sans-serif; font-size: 90%; vertical-align: sub;">3 <span style="font-family: Arial,Helvetica,sans-serif; font-size: 90%;">O <span style="font-family: Arial,Helvetica,sans-serif; font-size: 90%; vertical-align: super;">+ <span style="font-family: Arial,Helvetica,sans-serif; font-size: 90%;"> (aq) + HSO <span style="font-family: Arial,Helvetica,sans-serif; font-size: 90%; vertical-align: sub;">4 <span style="font-family: Arial,Helvetica,sans-serif; font-size: 90%;"> (aq)
 * 3) <span style="font-family: Arial,Helvetica,sans-serif; font-size: 90%;">HSO <span style="font-family: Arial,Helvetica,sans-serif; font-size: 90%; vertical-align: sub;">4 <span style="font-family: Arial,Helvetica,sans-serif; font-size: 90%;"> (aq) + H <span style="font-family: Arial,Helvetica,sans-serif; font-size: 90%; vertical-align: sub;">2 <span style="font-family: Arial,Helvetica,sans-serif; font-size: 90%;">O (l) → H <span style="font-family: Arial,Helvetica,sans-serif; font-size: 90%; vertical-align: sub;">3 <span style="font-family: Arial,Helvetica,sans-serif; font-size: 90%;">O <span style="font-family: Arial,Helvetica,sans-serif; font-size: 90%; vertical-align: super;">+ <span style="font-family: Arial,Helvetica,sans-serif; font-size: 90%;"> (aq) + SO <span style="font-family: Arial,Helvetica,sans-serif; font-size: 90%; vertical-align: sub;">4 <span style="font-family: Arial,Helvetica,sans-serif; font-size: 90%; vertical-align: super;">2- <span style="font-family: Arial,Helvetica,sans-serif; font-size: 90%;"> (aq)
 * <span style="font-family: Arial,Helvetica,sans-serif; font-size: 90%;">Nitrogen Combustion
 * 1) <span style="font-family: Arial,Helvetica,sans-serif; font-size: 90%;">4NO <span style="font-family: Arial,Helvetica,sans-serif; font-size: 90%; vertical-align: sub;">2 <span style="font-family: Arial,Helvetica,sans-serif; font-size: 90%;"> (g) + 2H <span style="font-family: Arial,Helvetica,sans-serif; font-size: 90%; vertical-align: sub;">2 <span style="font-family: Arial,Helvetica,sans-serif; font-size: 90%;">O (l)+ O2 (g) → 4HNO <span style="font-family: Arial,Helvetica,sans-serif; font-size: 90%; vertical-align: sub;">3 <span style="font-family: Arial,Helvetica,sans-serif; font-size: 90%;"> (aq)
 * 2) <span style="font-family: Arial,Helvetica,sans-serif; font-size: 90%;">HNO <span style="font-family: Arial,Helvetica,sans-serif; font-size: 90%; vertical-align: sub;">3 <span style="font-family: Arial,Helvetica,sans-serif; font-size: 90%;"> (aq) + H <span style="font-family: Arial,Helvetica,sans-serif; font-size: 90%; vertical-align: sub;">2 <span style="font-family: Arial,Helvetica,sans-serif; font-size: 90%;">O (l) → H <span style="font-family: Arial,Helvetica,sans-serif; font-size: 90%; vertical-align: sub;">3 <span style="font-family: Arial,Helvetica,sans-serif; font-size: 90%;">O <span style="font-family: Arial,Helvetica,sans-serif; font-size: 90%; vertical-align: super;">+ <span style="font-family: Arial,Helvetica,sans-serif; font-size: 90%;"> (aq) + NO <span style="font-family: Arial,Helvetica,sans-serif; font-size: 90%; vertical-align: sub;">3 <span style="font-family: Arial,Helvetica,sans-serif; font-size: 90%; vertical-align: super;">- <span style="font-family: Arial,Helvetica,sans-serif; font-size: 90%;"> (aq)

These pollutants that contribute to acid rain come from two primary sources: the burning of sulfur-rich coal, and the combustion of gasoline. The burning of sulfur-rich coal occurs primarily in the eastern part of the United States in order to heat water to produce electricity. Although the combusion of gasoline occurs throughout the United States, it is a larger problem in the western part of the United States where planned cities have created urban sprawl that more necessitates cars in order to get around.

The effects of acid rain are numerous on society. Acid rain generally deposits the NO x and SO x pollutants lower in the atmosphere, contributing to smog and aggrivating individual's health problems such as asthma and bronchitis. Acid rain also has the more debilitating effect to catalyze the production of rust in iron and steel, which is particularly troubling given the construction of many of our bridges and buildings. This rust reaction occurs as hydronium ions produced in acid rain react with oxygen and iron to create the rust. The reaction occurs as:
 * 1) 4Fe (s) + 2O 2 (g) + 8H 3 O + (aq) → 4Fe 2+ (aq) + 12H 2 O (l)
 * 2) 4FE 2+ (aq) + O 2 (g) + 12H 2 O (l) → 2Fe 2 O 3 (s) + 8H 3 O + (aq)

Hydronium ions produced during acid rain can also eat away at our culture by dissolving many of our marble and limestone landmarks like statues. This occurs as marble reacts with hydronium ions to produce carbon dioxide gas, liquid water, and aqueous Ca2+.

==Water Filtration== Water filtration is the process of creating safe drinking water by subjecting water to multiple processes to remove pollutants, bacteria, microbes, as well as improve clarity and taste. In most municipalities, water filtration follows this general process:
 * 1) Pre-filtration: involves the removal of large debris from the water supply such as branches and roots.
 * 2) pH adjustment: pure water as a pH of 7, and ocean water has a slightly higher pH of 8.3. In order to adjust the pH of municipal water supplies, cities often add chemicals such as lime, soda ash, or sodium hydroxide to raise the pH if it is too low, or they use a variety of acids to lower the pH if it is too high.
 * 3) Flocculation: is a process used to remove finer particles from the water which may house dangerous microbes, as well as improves the clarity of the water. The process consists of adding usually ammonium hydroxide and calcium chloride to the supply. As the chemicals are agitated, they form a gel precipitate known as floc which sticks to the sand and other particles in the water. After agitation, the water is held in a settling tank and the floc is allowed to float to the top.
 * 4) Sand and coal filtration: After flocculation, the water is often vertically filtered through a filter that contains sand and coal. This filter removes the floc from the water as well as other organic compounds. This step seeks to improve the taste and smell of the water.
 * 5) Chlorine Disinfection: is a process used to kill micro-organisms such as viruses and bacteria. The process often occurs by adding chlorine compounds such as chlorine, chloramine, chlorine dioxide, or sodium hypochlorite. These all react with water to produce calcium hypochlorite, which kills the viruses and bacteria. This step also helps improve the taste of water.

The most controversial step to the water filtration process is often the chlorine disinfection step. Chlorine and its various compounds can sometimes be reliable as international relations and poor roadways in less developed nations prevent the transport of chlorine. Chlorine compounds also have potentially hazardous effects, too. Therefore, some municipalities employ alternatives to chlorine disinfection, including ozone and UV-C disinfection. Ozone disinfection is the use of Ozone, O 3, to remove the viruses and bacteria from water. This particular method is considered good because it requires a lower concentration to remove bacteria than chlorine disinfection. One major drawback to this method, however, is that it is often only cost-effective at large-scale plants. Despite the cost, it is the most common form of water disinfection used in Europe. Another alternative to chlorine disinfection, UV-C disinfection, is also highly effective at removing bacteria from the water supply and is more cost-effective on smaller scales. The major drawback to both of these alternatives is that they dissapate quickly, leaving the water vulnerable to infection after it has left the water filtration plant and before it reaches its destination. It is therefore necessary in both processes to add small doses of chlorine to the water to protect the water on its way to the consumer.

Desalination is an umbrella of processes which seek to remove salt from salt water in order to make it drinkable. The two major processes of desalination include distillation and reverse osmosis. Distillation is the process of boiling water and collecting the pure, condensed water, while leaving salt and other impurities behind. Reverse osmosis is the act of forcing the water through a semi-permeable membrane which uses concentration gradients to remove salt from the water. Though both of these processes have the potential to bring safe drinking water to areas where ocean water is far more abundant than fresh water, they are still impractical because the processes require a lot of energy.
 * Desalination**

Random Facts

 * 780 million people lack access to an improved water source
 * 3.41 million people die each year from water, sanitation and hygiene-related causes each year
 * The water and sanitation crisis claims more lives through disease than any war claims through guns
 * People living informal settlements (i.e. slums) often pay 5-10 times more per liter of water than wealthy people living in the same city
 * An American taking a five-minute shower uses more water than the average person in a developing country slum uses for an entire day
 * <span style="color: #333333; font-family: Helvetica,Arial,sans-serif;">Roughly 70 percent of an adult’s body is made up of water
 * <span style="color: #333333; font-family: Helvetica,Arial,sans-serif;">At birth, water accounts for approximately 80 percent of an infant’s body weight
 * <span style="color: #333333; font-family: Helvetica,Arial,sans-serif;">A healthy person can drink about three gallons (48 cups) of water per day
 * <span style="color: #333333; font-family: Helvetica,Arial,sans-serif;">Drinking too much water too quickly can lead to water intoxication. Water intoxication occurs when water dilutes the sodium level in the bloodstream and causes an imbalance of water in the brain
 * <span style="color: #333333; font-family: Helvetica,Arial,sans-serif;">Water intoxication is most likely to occur during periods of intense athletic performance
 * <span style="color: #333333; font-family: Helvetica,Arial,sans-serif;">While the daily recommended amount of water is eight cups per day, not all of this water must be consumed in the liquid form. Nearly every food or drink item provides some water to the body
 * <span style="color: #333333; font-family: Helvetica,Arial,sans-serif;">Soft drinks, coffee, and tea, while made up almost entirely of water, also contain caffeine. Caffeine can act as a mild diuretic, preventing water from traveling to necessary locations in the body
 * <span style="color: #333333; font-family: Helvetica,Arial,sans-serif;">Pure water (solely hydrogen and oxygen atoms) has a neutral pH of 7, which is neither acidic nor basic
 * <span style="color: #333333; font-family: Helvetica,Arial,sans-serif;">Water dissolves more substances than any other liquid. Wherever it travels, water carries chemicals, minerals, and nutrients with it.
 * <span style="color: #333333; font-family: Helvetica,Arial,sans-serif;">Somewhere between 70 and 75 percent of the earth’s surface is covered with water
 * <span style="color: #333333; font-family: Helvetica,Arial,sans-serif;">Much more fresh water is stored under the ground in aquifers than on the earth’s surface
 * <span style="color: #333333; font-family: Helvetica,Arial,sans-serif;">The earth is a closed system, similar to a terrarium, meaning that it rarely loses or gains extra matter. The same water that existed on the earth millions of years ago is still present today
 * <span style="color: #333333; font-family: Helvetica,Arial,sans-serif;">The total amount of water on the earth is about 326 million cubic miles of water
 * <span style="color: #333333; font-family: Helvetica,Arial,sans-serif;">Of all the water on the earth, humans can used only about three tenths of a percent of this water. Such usable water is found in groundwater aquifers, rivers, and freshwater lakes
 * <span style="color: #333333; font-family: Helvetica,Arial,sans-serif;">The United States uses about 346,000 million gallons of fresh water every day
 * <span style="color: #333333; font-family: Helvetica,Arial,sans-serif;">The United States uses nearly 80 percent of its water for irrigation and thermoelectric power
 * <span style="color: #333333; font-family: Helvetica,Arial,sans-serif;">The average person in the United States uses anywhere from 80-100 gallons of water per day. Flushing the toilet actually takes up the largest amount of this water
 * <span style="color: #333333; font-family: Helvetica,Arial,sans-serif;">Approximately 85 percent of U.S. residents receive their water from public water facilities. The remaining 15 percent supply their own water from private wells or other sources
 * <span style="color: #333333; font-family: Helvetica,Arial,sans-serif;">By the time a person feels thirsty, his or her body has lost over 1 percent of its total water amount
 * <span style="color: #333333; font-family: Helvetica,Arial,sans-serif;">The weight a person loses directly after intense physical activity is weight from water, not fat
 * <span style="color: #333333; font-family: Helvetica,Arial,sans-serif;">Water has a boiling point of 100 degrees celsius and a freezing point of 0 degrees celsius
 * The boiling point of water is very high compared to other elements because of hydrogen bonding
 * The RDA recommends drinking 500ml of water a day.


 * <span style="color: #333333; font-family: Helvetica,Arial,sans-serif;">Dehydration: **
 * dehydration** is defined as the excessive loss of body fluid. It is literally the removal of water from an object; however, in physiological terms, it entails a deficiency of fluid within an organism. Dehydration of skin and mucous membranes can be called medical dryness.

There are three types of dehydration: hypotonic or hyponatremic (primarily a loss of electrolytes, sodium in particular), hypertonic or hypernatremic (primarily a loss of water), and isotonic or isonatremic (equal loss of water and electrolytes).[2home] In humans, the most commonly seen type of dehydration by far is isotonic (isonatraemic) dehydration which effectively equates with hypovolemia, but the distinction of isotonic from hypotonic or hypertonic dehydration may be important when treating people who become dehydrated. Physiologically, dehydration, despite the name, does not simply mean loss of water, as water and solutes (mainly sodium) are usually lost in roughly equal quantities to how they exist in blood plasma. In hypotonic dehydration, intravascular water shifts to the extravascular space, exaggerating intravascular volume depletion for a given amount of total body water loss. Neurological complications can occur in hypotonic and hypertonic states. The former can lead to seizures, while the latter can lead to osmotic cerebral edema upon rapid rehydration.[3home]

When you feel thirsty that means that the dehydration has already reached your throat and you have been dehydrated for a while. Most of the time when you feel hungry you are actually thirsty and need to drink water.

<span style="color: #333333; font-family: Helvetica,Arial,sans-serif;">Additional Resources and Related Pages

 * [|Water]
 * [|Properties of Water]
 * [|"How Water Works"]
 * [|Water Purification]
 * Dihydrogen Monoxide
 * [|Desalination]

Religion
Water is considered a purifier in most religions. Major faiths that incorporate ritual washing include Christianity, Hinduism, Islam, Judaism, Rastafari movement, Shinto, Taoism, and Wicca. Immersion of a person in water is a central sacrament of Christianity (where it is called baptism); it is also a part of the practice of other religions, including Islam (//Ghusl//), Judaism (// mikvah //) and Sikhism (//Amrit Sanskar//). In addition, a ritual bath in pure water is performed for the dead in many religions including Islam and Judaism. In Islam, the five daily prayers can be done in most cases after completing washing certain parts of the body using clean water (//wudu//), unless water is unavailable (see //Tayammum//). In Shinto, water is used in almost all rituals to cleanse a person or an area (e.g., in the ritual of //misogi//). Water is mentioned numerous times in the Bible, for example: "The earth was formed out of water and by water" (NIV). In the Qur'an it is stated that "Living things are made of water" and it is often used to describe paradise.

**Did you know?**
<span style="background-color: #ffffff; color: #151515; font-family: 'Lucida Sans Unicode','Lucida Grande','Lucida Sans',Arial,sans-serif;">Fluoride is voluntarily added to some drinking water systems as a public health measure for reducing the incidence of cavities among the treated population. The decision to fluoridate a water supply is made by the State or local municipality and is not mandated by EPA or any other Federal entity. The Centers for Disease Control and Prevention (CDC) provides recommendations about the optimal levels of fluoride in drinking water in order to prevent tooth decay. Information about CDC's recommendations can be found at: <span style="background-color: #ffffff; color: #4298aa; font-family: 'Lucida Sans Unicode','Lucida Grande','Lucida Sans',Arial,sans-serif; text-decoration: none;">[]