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Matter organizes into various phases or states of matter depending on its constituents and external factors like pressure and temperature.In common temperatures and pressures, atoms form the three classical states of matter: solid, liquid and gas.
The term phase is sometimes used as a synonym for state of matter, but it is possible for a single compound to form different phases that are in the same state of matter. For example, ice is the solid state of water, but there are multiple phases of ice with different crystal structures, which are formed at different pressures and temperatures.
Water is a well-known example of such a material. For example, water ice is ordinarily found in the hexagonal form ice I h, but can also exist as the cubic ice I c, the rhombohedral ice II, and many other forms. Polymorphism is the ability of a solid to exist in more than one crystal form. For pure chemical elements, polymorphism is known as ...
Four more elements have melting points slightly above room temperature: francium, caesium, gallium and rubidium. [1] In addition, certain mixtures of elements are liquid at room temperature, even if the individual elements are solid under the same conditions (see eutectic mixture). An example is the sodium-potassium metal alloy NaK. [2]
Water scarcity is also caused by production of water intensive products. For example, cotton: 1 kg of cotton—equivalent of a pair of jeans—requires 10.9 cubic metres (380 cu ft) water to produce. While cotton accounts for 2.4% of world water use, the water is consumed in regions that are already at a risk of water shortage.
Log-lin pressure-temperature phase diagram of water. The Roman numerals correspond to some ice phases listed below. The phases of ice are all possible states of matter for water as a solid. Variations in pressure and temperature give rise to different phases, which have varying properties and molecular geometries.
By the time of Antoine Lavoisier, for example, a list of elements would no longer refer to classical elements. [50] Some modern scientists see a parallel between the classical elements and the four states of matter: solid, liquid, gas and weakly ionized plasma. [51]
Water (H 2 O) is a polar inorganic compound that is at room temperature a tasteless and odorless liquid, which is nearly colorless apart from an inherent hint of blue.It is by far the most studied chemical compound [20] and is described as the "universal solvent" [21] and the "solvent of life". [22]