Water

Cristina Lucchese

My mole was designed to be the H2O compound, water. A mole shows the number of atoms in one gram atomic mass of an element. A mole measures the chemical amount of a substance. The number of moles equals 6.02 x 10 . The word mole can refer to anything 6.02 x 10 times; it is similar to the word dozen. This number is also know as Avogadro's number. The letter N is used to represent Avogadro's number. Amedeo Avogadro's work led to the determination of this number, that's why it is called Avogadro's number.

The common name applied to the liquid state of the hydrogen-oxygen compound H2O water. The ancient philosophers regarded water as a basic element illustrating all liquid substances. This view was not thrown out by scientists until the later half of the 18th century. In 1781, British chemist Henry Cavendish showed that water was obtained by the combustion of hydrogen air. Two years later, the French chemist Antoine Lavoisier proved that water was not an element, but a compound of oxygen and hydrogen. Then in 1804, French chemist Joseph Louis Gay-Lussac and German naturalist Alexander von Humboldt demonstrated that water consisted of two volumes of hydrogen to one of oxygen, as shown by the formula H2O. This means that each tiny molecule of water contains one atom of oxygen and two atoms of hydrogen. Hydrogen by itself is a very light gas which is frequently used to inflate balloons or airships. Oxygen is another gas which makes up about 23 percent of our atmosphere. All life needs oxygen, without it a person would die in a few minutes. When hydrogen and oxygen are thoroughly mixed, they can be ignited with a spark; they will unite with an explosion and form water. Together, hydrogen and oxygen make up about 90 percent of the mass of the earth's water.

Water is an odorless, tasteless, clear, colorless liquid that appears blue when viewed through a thickness of 6m. The color results not only from physical causes but also from impurities. Water has an unusually high boiling point at 100 degrees Celsius and freezing point at 0 degrees Celsius. These differences result from the strong attraction that each water molecule has for others, so that the energy required to melt the solid and boil the liquid is greater than might be predicted. Water also shows unusual volume changes with temperature. As warm water cools, it contracts until it reaches its maximum density at 4 degrees Celsius and expands upon freezing. Because most substances are somewhat soluble in water, it is frequently called the universal solvent. Water combines with certain slats to form hydrates. It reacts with metal oxides to form acids. It acts as a catalyst in many important chemical reactions.

Water is the only substance that occurs at ordinary temperatures in all three states of matter, which are as a solid, liquid, and gas. As a solid, or ice, it is found as glaciers and ice caps, on water surfaces in winter, as snow, hail, and frost, and as clouds formed of ice crystals. It occurs in the liquid state as rain clouds formed of water droplets, and on vegetation as dew. Also, it covers three-quarters of the earth's surface in the forms of swamps, lakes, rivers, and oceans. As a gas, or water vapor, it occurs as fog, steam, and clouds.

Water is a major constituent of living matter. Over two thirds of the human body is water. Blood is 90 percent water, and even muscles contain 80 to 90 percent. A normally healthy person can live only seven to ten days without water. To keep this water supply up to normal, the average man takes in about a ton of water each year, either as pure water, which he drinks or in the food he eats. From 50 to 90 percent of the weight of living organisms is water. Protoplasm, the basic material of living cells, consists of a solution in water of fats, carbohydrates, proteins, salts, and similar chemicals. Water acts as a solvent, transporting, combining, and chemically breaking down these substances. Blood in animals and sap in plants consist largely of water and serve to transport food and remove waste material. Water also plays a key role in the metabolic breakdown of such essential molecules as proteins and carbohydrates.

Everything we do has some connection with water. From eating a vegetable or fruit which contains water to taking a shower. Some do not realize how much water is apart of their everyday lives. Humans cannot survive without water and neither can our earth. H2O is a very important compound that interacts in our lives every day.