empirical formula(redirected from Chemical composition)
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formula[for´mu-lah] (pl. formulas, for´mulae) (L.)
1. an expression, using numbers or symbols, giving the directions for preparing a compound (such as a medicine) or giving a procedure to follow to obtain a desired result.
2. a mixture for feeding an infant, usually with cow's milk as a base, supplemented with vitamins and minerals. Various formulas are available, differing in protein, fat, and carbohydrate content in order to meet the nutritional requirements or restrictions of individual infants.
chemical formula a combination of symbols used to express the chemical components of a substance.
empirical formula a chemical formula that expresses the proportions of the elements present in a substance.
molecular formula a chemical formula expressing the number of each element present in a substance, without indicating how they are linked.
spatial formula (stereochemical formula) a chemical formula giving the numbers of atoms of each element present in a molecule of a substance, which atom is linked to which, the types of linkages involved, and the relative positions of the atoms in space.
structural formula a chemical formula showing the spatial arrangement of the atoms and the linkage of every atom.
Miller-Keane Encyclopedia and Dictionary of Medicine, Nursing, and Allied Health, Seventh Edition. © 2003 by Saunders, an imprint of Elsevier, Inc. All rights reserved.