Humber Admissions Practice Test

What does the Law of Multiple Proportions state?

1. Elements combine in only one ratio

2. Elements can combine in different ratios to form different compounds

3. Only compounds have multiple proportions

4. All compounds contain the same elements

The correct answer is: Elements can combine in different ratios to form different compounds

The Law of Multiple Proportions is a fundamental principle in chemistry that describes how different elements can combine in various ratios to create different compounds. This law asserts that when two elements form more than one compound, the masses of one element that combine with a fixed mass of the other element are in ratios of small whole numbers. Hence, when you have two elements, say A and B, that can form different compounds, the quantities of B that combine with a fixed amount of A will be in simple whole number ratios, which illustrates the idea that elements can combine in different proportions to form distinct chemical substances. This understanding is critical for comprehending how compounds are formed and the relationships between various chemical substances. In contrast, the other choices do not accurately express this concept. For instance, stating that elements combine in only one ratio would negate the idea of multiple compounds forming from the same elements, while the notion that only compounds have multiple proportions overlooks the underlying principle that it is the combination of elements that defines the existence of multiple proportions. Finally, claiming that all compounds contain the same elements is misleading, since compounds can vary significantly in composition and properties based on which elements are combined and in what ratios.