Sodium reacts with oxygen in air to form two compounds: sodium oxide and sodium peroxide. In forming sodium oxide, 23.0 g of sodium combines with 8.0 g of hydrogen. In forming sodium peroxide, 23.0 g of sodium combines with 16.0 g of oxygen. (b) What fundamental law does this experiment demonstrate?

Verified step by step guidance

1. First, let's identify the two reactions that are taking place. In the first reaction, sodium (Na) is reacting with oxygen (O2) to form sodium oxide (Na2O). In the second reaction, sodium (Na) is reacting with oxygen (O2) to form sodium peroxide (Na2O2).
2. Next, let's look at the masses of the reactants in each reaction. In the first reaction, 23.0 g of sodium reacts with 8.0 g of oxygen. In the second reaction, the same amount of sodium (23.0 g) reacts with a different amount of oxygen (16.0 g).
3. Despite the different amounts of oxygen used in each reaction, the amount of sodium remains constant. This is an important observation.
4. This observation demonstrates the Law of Constant Composition (or Law of Definite Proportions), which states that a given compound always contains exactly the same proportion of elements by mass. In this case, regardless of the amount of oxygen present, the ratio of the mass of sodium to the mass of the compound (sodium oxide or sodium peroxide) remains constant.
5. Another law that is demonstrated here is the Law of Conservation of Mass, which states that matter cannot be created or destroyed in a chemical reaction. The total mass of the reactants (sodium and oxygen) is equal to the total mass of the products (sodium oxide or sodium peroxide) in each reaction.

Key Concepts

Law of Conservation of Mass

The Law of Conservation of Mass states that mass is neither created nor destroyed in a chemical reaction. This principle implies that the total mass of reactants must equal the total mass of products. In the given reaction, the mass of sodium and oxygen used to form sodium oxide and sodium peroxide reflects this law, as the combined mass of the products equals the mass of the reactants.

Law of Definite Proportions

The Law of Definite Proportions asserts that a chemical compound always contains its component elements in fixed ratio by mass. In this experiment, sodium oxide and sodium peroxide are formed from sodium and oxygen in specific mass ratios, demonstrating that regardless of the amount of sodium used, the ratio of sodium to oxygen in each compound remains constant.

Stoichiometry

Stoichiometry is the calculation of reactants and products in chemical reactions based on the balanced chemical equation. It allows chemists to predict the quantities of substances consumed and produced in a reaction. In this case, stoichiometry helps to understand how the specific masses of sodium and oxygen lead to the formation of sodium oxide and sodium peroxide, illustrating the quantitative relationships in the reaction.