Law of multiple proportions

The law of multiple proportions states that the mass fractions of the elements in all the chemical compounds of the same elements are in an integer ratio.

John Dalton formulated the law in 1808, based on the law of constant proportions. It was based Dalton in his time very controversial atomic hypothesis.

Examples

• Sulfur is found in the compounds SO2 and SO3 ago with oxygen in the mass ratios of 1:1 and 2:3. In two parts by mass of sulfur dioxide sulfur come in two parts by weight of oxygen, sulfur trioxide come in two parts by mass of sulfur in three parts by weight of oxygen. Three and two relate to each other in the ratio of small whole numbers, namely in the ratio 3:2. Oxygen is found in these compounds in the mass ratios of 1:1 ( or 2:2 ) and 3:2 before ( the percentage of oxygen that is always related to the same two mass fractions of sulfur). Two and three relate to each other in the ratio of small whole numbers, namely in the ratio 2:3.

• Water and hydrogen peroxide from hydrogen and oxygen exist. In hydrogen, however, is for the same hydrogen content exactly twice as much oxygen as contained in the water.

• In the five nitrogen oxides are coming to a certain amount of nitrogen amounts of oxygen in the ratio of 1:2:3:4:5.