law of constant proportion

Thân thiện

A chemistry teacher draws a diagram of water molecules on the board to illustrate the law of constant proportion.

Definition

1. Noun:
   • (Chemistry): A fundamental chemical law stating that a given chemical compound always contains its constituent elements in fixed and constant proportions by mass, regardless of its source or method of preparation.

Usage

• The law of constant proportion is a foundational principle in chemistry, essential for understanding chemical formulas and stoichiometry.
• It is used to describe and validate the purity and composition of a chemical substance.
• This law applies to pure chemical compounds but not to mixtures or non-stoichiometric compounds.

Examples

• Noun:
  • Water always obeys the law of constant proportion, consisting of hydrogen and oxygen in a mass ratio of approximately 1:8.
  • The discovery of the law of constant proportion by Joseph Proust was crucial for the development of modern atomic theory.
  • Analyzing a sample to see if it conforms to the law of constant proportion is a standard test for a compound's purity.

Advanced Usage

• "To obey/uphold the law of constant proportion": To behave in accordance with this principle.
  • All pure samples of sodium chloride (table salt) must obey the law of constant proportion.
• "A demonstration/proof of the law of constant proportion": An experiment or evidence that validates the law.
  • The consistent composition of carbon dioxide from different sources serves as a proof of the law of constant proportion.

Variants and Related Words

• Law of definite proportions: This is a direct synonym and the more commonly used name for the same principle.
• Proust's Law: An alternative name referencing the chemist Joseph Louis Proust, who formulated the law.

Synonyms

• Law of definite proportions
• Proust's Law

Related Concepts (Not Synonyms)

• Law of multiple proportions: A related but distinct chemical law formulated by John Dalton, stating that when two elements form more than one compound, the ratios of the masses of the second element that combine with a fixed mass of the first element are ratios of small whole numbers.
• Stoichiometry: The area of chemistry that is fundamentally based on the laws of constant and multiple proportions, concerning the quantitative relationships between reactants and products in chemical reactions.

Học thuật

Noun

1. (chemistry) law stating that every pure substance always contains the same elements combined in the same proportions by weight

Từ đồng nghĩa

• law of definite proportions