What is lacking by definition in an anhydrous substance?
Anhydrous solutions can be dried using a range of drying agents. Typically following a workup the organic extract is dried using magnesium sulfate or a similar drying agent to remove most remaining water. Several substances that exist as gases at standard conditions of temperature and pressure are commonly used as concentrated aqueous solutions. To clarify that it is the gaseous form that is being referred to, the term "anhydrous" is prefixed to the name of the substance: Reactions which produce water can be kept dry using a Dean-Stark apparatus. Anhydrous A substance is anhydrous if it contains no water. Many processes
Chemical substance regard. A chemical substance may well be defined as "any material with a definite chemical composition" in an introductory general chemistry textbook. According to this definition a chemical substance can either be a pure chemical element or a pure chemical compound. But, there are exceptions to this definition; a pure substance can also be defined as a form of matter that has both definite composition and distinct properties. The chemical substance index published by CAS also includes several alloys of uncertain composition. Non-stoichiometric compounds are a special case (in inorganic chemistry) that violates the law of constant composition, and for