Definition

Noun: 1. A principle in chemistry: This law states that if two different elements each combine separately with a fixed mass of a third element, the ratio of the masses in which they do so is either the same as, or a simple multiple of, the ratio of the masses in which they combine with each other. It is also known as the law of equivalent proportions.

Usage

• This law is a fundamental concept in stoichiometry and helps establish equivalent weights of elements.
• It is often discussed alongside the law of definite proportions and the law of multiple proportions to describe the quantitative relationships in chemical compounds.

Examples

Advanced Usage

• The law can be expressed mathematically. If element A combines with element C in a mass ratio , and element B combines with element C in a mass ratio , then when A and B combine, they will do so in a mass ratio of or a simple fraction/multiple thereof (e.g., ).

Variants and Related Words

• Law of equivalent proportions: A direct synonym for the law of reciprocal proportions.
• Stoichiometry: The branch of chemistry that deals with the quantitative relationships of reactants and products in chemical reactions, founded upon laws like this one.
• Chemical equivalent: The mass of an element that combines with or displaces a standard mass of another element, a concept derived from this law.

Synonyms

• Law of equivalent proportions

Related Concepts (Not Phrasal Verbs or Idioms)

• Law of definite proportions: States that a given chemical compound always contains its component elements in fixed ratio by mass.
• Law of multiple proportions: States that when two elements form more than one compound, the masses of one element that combine with a fixed mass of the other are in a ratio of small whole numbers.

Noun

1. (chemistry) law stating that the proportions in which two elements separately combine with a third element are also the proportions in which they combine together