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The specific weight, also known as the unit weight (symbol γ, the Greek letter gamma), is a volume-specific quantity defined as the weight W divided by the volume V of a material: = / Equivalently, it may also be formulated as the product of density, ρ, and gravity acceleration, g: = Its unit of measurement in the International System of Units (SI) is newton per cubic metre (N/m 3), with ...
Quantities, Units and Symbols in Physical Chemistry, also known as the Green Book, is a compilation of terms and symbols widely used in the field of physical chemistry. It also includes a table of physical constants , tables listing the properties of elementary particles , chemical elements , and nuclides , and information about conversion ...
Liquid hydrogen (H 2 (l)) is the liquid state of the element hydrogen. Hydrogen is found naturally in the molecular H 2 form. [4] To exist as a liquid, H 2 must be cooled below its critical point of 33 K. However, for it to be in a fully liquid state at atmospheric pressure, H 2 needs to be cooled to 20.28 K (−252.87 °C; −423.17 °F). [5]
Usually the symbol for the quantity with a subscript of some reference to the quantity is used, or the quantity is written with the reference to the chemical in round brackets. For example, the mass of water might be written in subscripts as m H 2 O , m water , m aq , m w (if clear from context) etc., or simply as m (H 2 O).
Density (volumetric mass density or specific mass) is a substance's mass per unit of volume.The symbol most often used for density is ρ (the lower case Greek letter rho), although the Latin letter D can also be used.
The statute standardized weight, length and volume as well as introduced the peny, ounce, pound, gallon and bushel. [4]: 73–74 In 1618, the London Pharmacopoeia (medicine compound catalog) adopted the Roman gallon [8] or congius [9] as a basic unit of volume and gave a conversion table to the apothecaries' units of weight. [8]
The weight of the displaced liquid can then be determined, and hence the relative density of the powder. A gas pycnometer , the gas-based manifestation of a pycnometer, compares the change in pressure caused by a measured change in a closed volume containing a reference (usually a steel sphere of known volume) with the change in pressure caused ...
A chemical tank is of necessity designed for a specific chemical. Chemicals have variable corrosion potentials, so the size and features of chemical tanks are diverse. Chemical resistance is usually the first priority in designing chemical tanks. Selected materials have to be as resistant to the chemical stored as design and economics allow.