What Set of the Three Figures Below Illustrates the Law of Multiple Proportions?
The law of multiple proportions is a fundamental principle in chemistry that states that when two elements combine to form more than one compound, the ratio of masses of one element that combines with a fixed mass of the other element can be expressed in small whole numbers. This law, proposed by John Dalton in the early 19th century, laid the foundation for our understanding of chemical reactions and the composition of compounds.
To illustrate the law of multiple proportions, let’s consider the three figures below:
Figure 1: Oxygen and Hydrogen
Compound 1: H2O (Water)
Compound 2: H2O2 (Hydrogen Peroxide)
Figure 2: Carbon and Oxygen
Compound 1: CO (Carbon Monoxide)
Compound 2: CO2 (Carbon Dioxide)
Figure 3: Nitrogen and Oxygen
Compound 1: NO (Nitric Oxide)
Compound 2: NO2 (Nitrogen Dioxide)
These three sets of compounds perfectly exemplify the law of multiple proportions. In each set, we have two compounds formed by the combination of the same elements, but in different ratios.
In Figure 1, we see that when hydrogen combines with oxygen, two different compounds are formed: water (H2O) and hydrogen peroxide (H2O2). The ratio of hydrogen to oxygen in water is 2:1, while in hydrogen peroxide, it is 1:1. This demonstrates the law of multiple proportions as the ratio of hydrogen to oxygen in the two compounds is expressed in small whole numbers.
Moving on to Figure 2, we observe the combination of carbon and oxygen. Carbon monoxide (CO) and carbon dioxide (CO2) are the two compounds formed. In carbon monoxide, the ratio of carbon to oxygen is 1:1, while in carbon dioxide, it is 1:2. Again, the law of multiple proportions is evident as the ratio of carbon to oxygen in the compounds is expressed in small whole numbers.
Lastly, Figure 3 involves the combination of nitrogen and oxygen. Nitric oxide (NO) and nitrogen dioxide (NO2) are the two compounds formed. The ratio of nitrogen to oxygen in nitric oxide is 1:1, while in nitrogen dioxide, it is 1:2. Once more, this fulfills the law of multiple proportions as the ratio of nitrogen to oxygen in the compounds is expressed in small whole numbers.
FAQs:
1. What is the significance of the law of multiple proportions?
The law of multiple proportions is significant because it provides evidence for the existence of atoms and their ability to combine in fixed ratios. It also helps explain the stoichiometry of chemical reactions and the composition of compounds.
2. How did Dalton contribute to the understanding of multiple proportions?
John Dalton’s atomic theory, which included the law of multiple proportions, revolutionized our understanding of chemical reactions. By proposing that elements are made up of indivisible particles called atoms, he explained how elements combine in fixed ratios to form compounds.
3. Can you provide another example of multiple proportions?
Certainly! Another classic example of multiple proportions is the combination of sulfur and oxygen. Sulfur dioxide (SO2) and sulfur trioxide (SO3) are two compounds formed. In sulfur dioxide, the ratio of sulfur to oxygen is 1:2, while in sulfur trioxide, it is 1:3.
4. Are there any exceptions to the law of multiple proportions?
While the law of multiple proportions holds true for many chemical combinations, there are a few exceptions. Some compounds, such as hydrogen peroxide (H2O2) or ozone (O3), do not follow the law as their ratios of elements cannot be expressed in small whole numbers.
5. How does the law of multiple proportions relate to the concept of molar ratios?
The law of multiple proportions is closely related to the concept of molar ratios. Molar ratios represent the ratios of moles of different substances in a chemical equation. The law of multiple proportions helps determine these ratios by establishing the fixed ratios in which elements combine to form compounds.
In conclusion, the three figures presented above provide clear examples of the law of multiple proportions. They demonstrate how different compounds can be formed by the combination of the same elements but in varying ratios. The law of multiple proportions, proposed by John Dalton, is a fundamental principle that underlies our understanding of chemical reactions and the composition of compounds.