Anhydrous Without water

Angstrom unit (A) A unit of length, one ten-millionth of a millimeter or one ten-thousandth of a micrometer long, anhydrous Without water, animal fibers See fibers, animal. anion An ion having a negative electric charge. 

Anhydrous Without water, dry. Describes a substance in which no water molecules are present. 

Some stable ionic compounds are capable of bonding to a certain number of molecules of water per formula unit. Thus, copper(II) sulfate forms the stable CuSO4-5H2O, with five molecules of water per CaiSO, unit. This type of compound is called a hydrate. The name of the compound is the name of the anhydrous (without water) compound with a designation for the number of water molecules appended. Thus, CaiS( ),-5I t,() is called copper(II) sulfate pentahydrate. The 5 multiples everything after it until the next centered dot or the end of the formula. Thus, included in CuSO4-5H2O are ten H atoms and nine O atoms (five from the water and four in the sulfate ion). 

Anhydrous Without water. Having no water of crYStalllzatlon. 

Formulas for hydrates are expressed by first writing the usual anhydrous (without water) formula for the compound and then adding a dot followed by the number of water... 

You probably recognized that HCl is a binary covalent compound that can be named by the rules given earlier in Section 4.10. According to those rules, HCl should be named hydrogen chloride. In fact, that is the correct name for the compound HCl that has not been dissolved in water and is represented in reaction equations by the notation HCl(g). Such compounds that have not been dissolved in water are said to be anhydrous (without water). However, when the gas is dissolved in water and represented in equations by the notation HCl(aq), it behaves as an acid and is given another name. The following rules are used to name acidic water solutions of such compounds ... 

---