hydrate(redirected from Pentahydrate)
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hydrate(hī`drāt), chemical compound that contains water. A common hydrate is the familiar blue vitriol, a crystalline form of cupric sulfatecupric sulfate
or copper (II) sulfate,
chemical compound, CuSO4, taking the form of white rhombohedral crystals or amorphous powder. It decomposes at 650°C; to cupric oxide (CuO).
..... Click the link for more information. . Chemically, it is cupric sulfate pentahydrate, CuSO4·5H2O. When a crystal of the substance is formed, five molecules of water (H2O) are combined in the crystal with each molecule of cupric sulfate (CuSO4). This water is called water of crystallization. When cupric sulfate pentahydrate is heated above 150°C; the water of crystallization is driven off and anhydrous cupric sulfate is formed. It has several properties different from the pentahydrate, e.g., color, density, and crystal structure. Glauber's saltGlauber's salt,
common name for sodium sulfate decahydrate, Na2SO4·10H2O; it occurs as white or colorless monoclinic crystals. Upon exposure to fairly dry air it effloresces, forming powdery anhydrous sodium sulfate.
..... Click the link for more information. is sodium sulfate decahydrate, Na2SO4·10H2O. Crystals of it readily give up their water of crystallization at ordinary temperatures, forming a powdery coating of the anhydrous salt; this phenomenon (efflorescence) is exhibited by many hydrates. The number of molecules of water present in a given hydrate is fixed. However, some substances form several different hydrates. There are four different hydrates of ferrous sulfate, each with its own unique physical properties. In organic chemistry a compound formed by addition of water to a carbon-carbon double bond is sometimes called a hydrate; it contains a hydroxyl functional group and usually cannot be dehydrated. In commerce a metal hydroxide is sometimes called a hydrate; e.g., calcium hydrate is calcium hydroxide.
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A form of a solid compound which has water in the form of H2 O molecules associated with it; for example, anhydrous copper sulfate is a white solid with the formula CuSO4, but when crystallized from water a blue crystalline solid with formula CuSO4·5H2 O results, and the water molecules are an integral part of the crystal.
A crystalline compound resulting from the combination of water and a gas; frequently a constituent of natural gas that is under pressure.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.
1. To combine with water or elements of water.
2. Hydrated lime.
McGraw-Hill Dictionary of Architecture and Construction. Copyright © 2003 by McGraw-Hill Companies, Inc.
1. a chemical compound containing water that is chemically combined with a substance and can usually be expelled without changing the constitution of the substance
2. a chemical compound that can dissociate reversibly into water and another compound. For example sulphuric acid (H2SO4) dissociates into sulphur trioxide (SO3) and water (H2O)
3. a chemical compound, such as a carbohydrate, that contains hydrogen and oxygen atoms in the ratio two to one
Collins Discovery Encyclopedia, 1st edition © HarperCollins Publishers 2005