Why particularly sillcon dioxide
Answers
Explanation:
Silicon dioxide is a natural chemical mix of silicon and oxygen that has uses in many food products as an anticaking agent. Silicon dioxide is generally safe as a food additive, though some agencies are calling for stricter guidelines about the quality and characteristics of the silicon dioxide found in foods.
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Answer:
Uses and Occurrence in Nature
Uses and Occurrence in NatureQuartz is the most common crystalline form of silica encountered in nature. Quartz is present as alpha and beta (high temperature) forms. Alpha quartz is the most common form, and is found in large quantities in many rocks and soils worldwide. That quartz is among the most abundant minerals in many, if not most, soils is a reflection of its chemical stability and resistance to weathering. Quartz is so prevalent that the term quartz is often used in place of crystalline silica. Exceptions to the generally widespread occurrence of quartz are the highly weathered soils of tropical regions, where even the resistant quartz has been lost through weathering processes. Tridymite and cristobalite are other fairly common forms of crystalline silica and are generally found in rocks formed at high temperature (e.g., volcanic rocks). Coesite and stishovite are two rare polymorphs formed at high pressure (e.g., meteorite impact craters and some ultra-high-pressure metamorphic rocks). Other than alpha quartz, all of these forms are thermodynamically metastable at earth surface temperatures and pressures and will slowly convert to alpha quartz given enough time (millions of years). Microcrystalline varieties of silica also include small grains of this material, possibly combined with amorphous silica. Tripoli, flint, chert, jasper, chalcedony, agate, onyx, and silica flour are examples.
Uses and Occurrence in NatureQuartz is the most common crystalline form of silica encountered in nature. Quartz is present as alpha and beta (high temperature) forms. Alpha quartz is the most common form, and is found in large quantities in many rocks and soils worldwide. That quartz is among the most abundant minerals in many, if not most, soils is a reflection of its chemical stability and resistance to weathering. Quartz is so prevalent that the term quartz is often used in place of crystalline silica. Exceptions to the generally widespread occurrence of quartz are the highly weathered soils of tropical regions, where even the resistant quartz has been lost through weathering processes. Tridymite and cristobalite are other fairly common forms of crystalline silica and are generally found in rocks formed at high temperature (e.g., volcanic rocks). Coesite and stishovite are two rare polymorphs formed at high pressure (e.g., meteorite impact craters and some ultra-high-pressure metamorphic rocks). Other than alpha quartz, all of these forms are thermodynamically metastable at earth surface temperatures and pressures and will slowly convert to alpha quartz given enough time (millions of years). Microcrystalline varieties of silica also include small grains of this material, possibly combined with amorphous silica. Tripoli, flint, chert, jasper, chalcedony, agate, onyx, and silica flour are examples.Silica is typically only one of many constituents of mineral dust. A wide array of other rock- and soil-forming minerals, including silicate and nonsilicate minerals may also be present. Nonetheless, crystalline silica can represent a large fraction of the respirable dust present in agricultural settings because quartz is so abundant in most soils. The proportion of quartz in respirable dust from soils will thus be related to soil mineralogy and the relative abundances of the sand (2000–50 μm diameter), silt (50–2 μm diameter), and clay (≤2 μm diameter) fractions in the soil. Other materials in which crystalline silica may be found include gravel, slate, diatomaceous earth, concrete, mortar, plaster, refractory materials, pottery clay, limestone, shale, bricks, an is required for crop production.
Explanation: