Law Of Multiple Proportions

Definition: Law Of Multiple Proportions

Law Of Multiple Proportions

Noun

1. (chemistry) law stating that when two elements can combine to form more than one compound the amounts of one of them that combines with a fixed amount of the other will exhibit a simple multiple relation.

Specialty Definition: Law of multiple proportions

In chemistry, the law of multiple proportions is one of the basic laws of stoichiometry, alongside the law of definite proportions. It is sometime's called Dalton's Law after its discoverer, the English chemist John Dalton.

One statement of the law is:

If two elements form more than one compound between them, then the ratios of the weights of the second element which combine with a fixed mass of the first element will be ratios of small whole numbers.

For example, considering two of the carbon oxides: CO and CO₂, 100 grams of carbon may react with 133 grams of oxygen to produce carbon monoxide, or with 267 grams of oxygen to produce carbon dioxide. The ratio of the masses of oxygen that can react with 100 grams of carbon is 266:133 ≈ 2:1, a ratio of small whole numbers.

John Dalton first expressed this observation in 1803. A few years previously, the French chemist Joseph Proust had proposed the law of definite proportions, which expressed that the elements combined to form compounds in certain well-defined proportions, rather than mixing in just any proportion. Careful study of the actual numerical values of these proportions led Dalton to propose his law of multiple proportions. This was an important step toward the atomic theory that he would propose later that year, and it laid the basis for chemical formulas for compounds.

The law of multiple proportions is best demonstrated using simple compounds. For example, if one tried to demonstrate it using the hydrocarbons decane (chemical formula C₁₀H₂₂) and undecane (C₁₁H₂₄), one would find that 100 grams of carbon could react with 18.46 grams of hydrogen to produce decane or with 18.31 grams of hydrogen to produce undecane, for a ratio of hydrogen masses of 121:120, which is hardly a ratio of "small" whole numbers.

Misspellings: Law Of Multiple Proportions

Alternative Orthography: Law Of Multiple Proportions

Hexadecimal (or equivalents, 770AD-1900s) (references)

4C 61 77 4F 66 4D 75 6C 74 69 70 6C 65 50 72 6F 70 6F 72 74 69 6F 6E 73

Leonardo da Vinci (1452-1519; backwards) (references)

Binary Code (1918-1938, probably earlier) (references)

01001100 01100001 01110111 00100000 01001111 01100110 00100000 01001101 01110101 01101100 01110100 01101001 01110000 01101100 01100101 00100000 01010000 01110010 01101111 01110000 01101111 01110010 01110100 01101001 01101111 01101110 01110011

HTML Code (1990) (references)

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ISO 10646 (1991-1993) (references)

004C 0061 0077 004F 0066 004D 0075 006C 0074 0069 0070 006C 0065 0050 0072 006F 0070 006F 0072 0074 0069 006F 006E 0073

Encryption (beginner's substitution cypher): (references)

Law Of Multiple Proportions

Definition: Law Of Multiple Proportions