hygroscopic
Information about hygroscopic
Hygroscopy is the ability of a substance to attract water molecules from the surrounding environment through either absorption or adsorption.
Hygroscopic substances include honey, glycerin, ethanol, methanol, concentrated sulfuric acid, methamphetamine, and concentrated sodium hydroxide (lye). Calcium chloride is so hygroscopic that it eventually dissolves in the water it absorbs: this property is called deliquescence (see below). Because of their affinity for atmospheric moisture, hygroscopic materials may need to be stored in sealed containers. When added to foods or other materials for the express purpose of maintaining moisture content, such substances are known as humectants.
Materials and compounds exhibit different hygroscopic properties, and this difference can lead to detrimental effects, such as stress concentration in composite materials. The amount a particular material or compound is affected by ambient moisture may be considered its coefficient of hygroscopic expansion (CHE) or coefficient of hygroscopic contraction (CHC)—the difference between the two terms being a difference in sign convention and a difference in point of view as to whether the difference in moisture leads to contraction or expansion.
A common example where difference in this hygroscopic property can be seen is in a paperback book cover. Often in a relatively moist environment the book cover will curl away from the rest of the book. The unlaminated side of the cover absorbs more moisture than the laminated side and increased in area, causing a stress that curls the cover toward the laminated side. This is similar to the function of a bi-metallic strip.
The similar sounding but unrelated word hydroscopic is sometimes used in error for hygroscopic. A hydroscope is an optical device used for making observations deep under water.
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Hygroscopic substances include honey, glycerin, ethanol, methanol, concentrated sulfuric acid, methamphetamine, and concentrated sodium hydroxide (lye). Calcium chloride is so hygroscopic that it eventually dissolves in the water it absorbs: this property is called deliquescence (see below). Because of their affinity for atmospheric moisture, hygroscopic materials may need to be stored in sealed containers. When added to foods or other materials for the express purpose of maintaining moisture content, such substances are known as humectants.
Materials and compounds exhibit different hygroscopic properties, and this difference can lead to detrimental effects, such as stress concentration in composite materials. The amount a particular material or compound is affected by ambient moisture may be considered its coefficient of hygroscopic expansion (CHE) or coefficient of hygroscopic contraction (CHC)—the difference between the two terms being a difference in sign convention and a difference in point of view as to whether the difference in moisture leads to contraction or expansion.
A common example where difference in this hygroscopic property can be seen is in a paperback book cover. Often in a relatively moist environment the book cover will curl away from the rest of the book. The unlaminated side of the cover absorbs more moisture than the laminated side and increased in area, causing a stress that curls the cover toward the laminated side. This is similar to the function of a bi-metallic strip.
The similar sounding but unrelated word hydroscopic is sometimes used in error for hygroscopic. A hydroscope is an optical device used for making observations deep under water.
Biology
The seeds of some grasses have hygroscopic extensions which bend with changes in humidity, enabling them to disperse over the ground. An example is Needle-and-Thread, Hesperostipa comata. Each seed has an awn that twists several turns when the seed is released. Increased moisture causes it to untwist, and upon drying to twist again; the seed is drilled into the ground. Children in the west call this the "crazy plant".Deliquescence
Deliquescent materials are substances (mostly salts) which have a strong affinity for moisture and will absorb relatively large amounts of water from the atmosphere if exposed to it, forming a liquid solution. Deliquescent salts include calcium chloride, magnesium chloride, zinc chloride, and the strong base sodium hydroxide. They are often used as desiccants.See also
Water is a common chemical substance that is essential to all known forms of life.[1] In typical usage, water refers only to its liquid form or state, but the substance also has a solid state, ice, and a gaseous state, water vapor.
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molecule is defined as a sufficiently stable electrically neutral group of at least two atoms in a definite arrangement held together by strong chemical bonds.[1][2] In organic chemistry and biochemistry, the term molecule
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natural environment, commonly referred to simply as the environment, is a term that comprises all living and non-living things that occur naturally on Earth or some part of it (e.g. the natural environment in a country).
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Absorption, in chemistry, is a physical or chemical phenomenon or a process in which atoms, molecules, or ions enter some bulk phase - gas, liquid or solid material. This is a different process from adsorption, since the molecules are taken up by the volume, not by surface.
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Adsorption is a process that occurs when a gas or liquid solute accumulates on the surface of a solid or, more rarely, a liquid (adsorbent), forming a molecular or atomic film (the adsorbate).
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Honey is a sweet and viscous fluid produced by honey bees (and some other species of bee), and derived from the nectar of flowers. According to the United States National Honey Board and various international food regulations, "honey stipulates a pure product that does not allow
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Glycerol is a chemical compound with the formula HOCH2CH(OH)CH2OH. This colorless, odorless, viscous liquid is widely used in pharmaceutical formulations.
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Ethanol, also known as ethyl alcohol, drinking alcohol or grain alcohol, is a flammable, colorless, slightly toxic chemical compound, and is best known as the alcohol found in alcoholic beverages.
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Methanol, also known as methyl alcohol, carbinol, wood alcohol, wood naptha or wood spirits, is a chemical compound with chemical formula CH3OH.
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Sulfuric (or sulphuric) acid, H2SO4, is a strong mineral acid. It is soluble in water at all concentrations. It was once known as oil of vitriol, coined by the 8th-century Arabian alchemist Jabir ibn Hayyan (Geber) after his discovery of the chemical.
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Methamphetamine (methylamphetamine or desoxyephedrine), popularly shortened to meth and also nicknamed "ice", is a psychostimulant and sympathomimetic drug.
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Sodium hydroxide (NaOH), also known as lye, caustic soda and sodium hydrate, is a caustic metallic base. Caustic soda forms a strong alkaline solution when dissolved in a solvent such as water.
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Lye is a caustic solution which is made from ashes and is used for glass, soap making, and certain food preparations and may refer to:
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- Soda lye, known as sodium hydroxide
- Potash lye, a less common name for potassium hydroxide
- Chamber lye, urine
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Calcium chloride is an ionic compound of calcium and chlorine. It is highly soluble in water and it is deliquescent. It is a salt that is solid at room temperature, and it behaves as a typical ionic halide.
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Earth's atmosphere is a layer of gases surrounding the planet Earth and retained by the Earth's gravity. It contains roughly (by molar content/volume) 78% nitrogen, 20.95% oxygen, 0.93% argon, 0.
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Moisture generally refers to the presence of water, often in trace amounts.
The moisture content is often an important aspect of various foodstuffs including cheese and many dried goods such as tea where excess moisture can promote bacterial growth, decay, molding, or
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The moisture content is often an important aspect of various foodstuffs including cheese and many dried goods such as tea where excess moisture can promote bacterial growth, decay, molding, or
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Water content or moisture content is the quantity of water contained in a material, such as soil (called soil moisture), rock, ceramics, or wood on a volumetric or gravimetric basis.
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A humectant is a hygroscopic substance. It is often a molecule with several hydrophilic groups, most often hydroxyl groups, but amines and carboxyl groups, sometimes esterified, can be encountered as well; the affinity to form hydrogen bonds with molecules of water is crucial here.
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Composite materials (or composites for short) are engineered materials made from two or more constituent materials with significantly different physical or chemical properties and which remain separate and distinct on a macroscopic level within the finished structure.
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bi-metallic strip is used to convert a temperature change into mechanical displacement. The strip consists of two strips of different metals which expand at different rates as they are heated, usually steel and copper.
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The word hydroscope is used to mean any of several instruments related to water. One kind denotes an instrument for seeing below the surface of water, such as a long tube fitted with various lenses so arranged that objects lying at the bottom can be reflected upon a screen on the
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Salt is a mineral essential for animal life, composed primarily of sodium chloride. Salt for human consumption is produced in different forms: unrefined salt (such as sea salt), refined salt (table salt), and iodized salt.
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In physical chemistry, chemical affinity, historically, refers to the "force" that causes chemical reactions.[1] A broad definition, used generally throughout history, is that chemical affinity is that whereby substances enter into or resist decomposition.
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Moisture generally refers to the presence of water, often in trace amounts.
The moisture content is often an important aspect of various foodstuffs including cheese and many dried goods such as tea where excess moisture can promote bacterial growth, decay, molding, or
..... Click the link for more information.
The moisture content is often an important aspect of various foodstuffs including cheese and many dried goods such as tea where excess moisture can promote bacterial growth, decay, molding, or
..... Click the link for more information.
Water is a common chemical substance that is essential to all known forms of life.[1] In typical usage, water refers only to its liquid form or state, but the substance also has a solid state, ice, and a gaseous state, water vapor.
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Earth's atmosphere is a layer of gases surrounding the planet Earth and retained by the Earth's gravity. It contains roughly (by molar content/volume) 78% nitrogen, 20.95% oxygen, 0.93% argon, 0.
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Liquid is one of the four principal states of matter. A liquid is a fluid that can freely form a distinct surface at the boundaries of its bulk material.
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Characteristics
A liquid's shape is determined by, not confined to, the container it fills...... Click the link for more information.
This article is about chemical solutions. For other uses, see Solution (disambiguation).
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Salt is a mineral essential for animal life, composed primarily of sodium chloride. Salt for human consumption is produced in different forms: unrefined salt (such as sea salt), refined salt (table salt), and iodized salt.
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Calcium chloride is an ionic compound of calcium and chlorine. It is highly soluble in water and it is deliquescent. It is a salt that is solid at room temperature, and it behaves as a typical ionic halide.
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