Definition

1. Noun:
   • The water present in hydrated compounds: "Water of hydration" refers to water molecules that are chemically bound within the crystalline structure of a salt or other compound, forming a hydrate. This water can often be removed by heating, leaving the anhydrous (water-free) form of the compound.

Usage

• "Water of hydration" is a technical term used primarily in chemistry and materials science. It is used to specify the water content integral to a hydrate's formula and structure.
• It is typically used in contexts discussing chemical formulas, stoichiometry, thermal analysis, and the properties of crystalline solids.

Examples

• Noun:
  • The formula CuSO₄·5H₂O indicates there are five molecules of water of hydration for each copper sulfate unit.
  • Upon heating, the blue crystals lost their water of hydration and turned into a white powder.
  • Calculating the percent mass of water of hydration is a common laboratory experiment.

Advanced Usage

• "Driven off as water of hydration": A phrase describing the process of removing this water, usually by heating.
  • When gypsum is heated, water of hydration is driven off to form plaster of Paris.
• The term is central to understanding and writing chemical formulas for hydrates, where it is denoted by a centered dot (·) followed by .

Variants and Related Words

• Hydrate (n): A compound that contains water of hydration.
  • Copper(II) sulfate pentahydrate is a common hydrate.
• Water of crystallization: A nearly synonymous term often used interchangeably with "water of hydration," emphasizing the water's role in forming the crystal lattice.
• Anhydrous (adj): Describing a substance from which all water of hydration has been removed.

Synonyms

• Crystal water
• Water of crystallization (Note: This is a very close synonym, though subtle contextual preferences may exist.)

Related Phrases

• Lose its water of hydration: To undergo dehydration.
  • The compound will lose its water of hydration if left in a dry atmosphere.
• Bound water: A more general term that can include water of hydration but also other forms of chemically or physically trapped water.

Noun

1. the water present in hydrated compounds