Definitions for

**"Law of multiple proportions"**When one element can combine with another to form more than one compound, the mass ratios of the elements in the compounds are simple whole-number ratios of each other. For example, in CO and in CO2, the oxygen-to-carbon ratios are 16:12 and 32:12, respectively. Note that the second ratio is exactly twice the first, because there are exactly twice as many oxygens in CO2 per carbon as there are in CO.

whenever two elements form more than one compound, the different masses of one element that combine with the same mass of the other element are in the ratio of small whole numbers.

When two elements form more than one compound, the masses of one element combining with a fixed mass of the other are in the ratio of small whole numbers