Final answer:
The law of definite proportions indicates that a chemical compound always contains the same proportion of elements by mass. The law of multiple proportions states that when two elements form more than one compound, the mass ratios of one element that combine with a fixed mass of another are small whole number ratios. Examples include the composition of water and the different carbon oxides.
Step-by-step explanation:
Laws of Definite Proportions and Multiple Proportions
The law of definite proportions states that a given chemical compound always contains the same elements in the exact same proportions by mass regardless of the sample or source. For example, water (H2O) will always consist of 11.19% hydrogen and 88.81% oxygen by mass, whether it's from a river or made in a lab. This law is important because it provides the basis for chemical formulas and stoichiometry in chemical reactions.
The law of multiple proportions states 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. For instance, carbon and oxygen can form carbon monoxide (CO) and carbon dioxide (CO2). In CO, 12 grams of carbon bond with 16 grams of oxygen, while in CO2, 12 grams of carbon bond with 32 grams of oxygen - which is an exact multiple of the mass of oxygen in CO.