Problem 47 - Chemistry Matter and Change

Question

Rust Iron and oxygen combine to form iron oxide, or rust. List the reactants and products of this reaction.

Step-by-Step Solution

Answer

In conclusion, the reactants in this reaction are iron (Fe) and oxygen (O₂), and the product is iron oxide (Fe₂O₃).

Step 1: Identify reactants and products

The first step in identifying the reactants and products is to understand the given information. The exercise states that iron (Fe) and oxygen (O2) react to form iron oxide, or rust. So, the reactants are iron and oxygen, while the product is iron oxide.

Step 2: Write the chemical reaction

Now, we will write down the balanced chemical equation for the reaction between iron and oxygen to form iron oxide: \[ 4 \, Fe \, (s) + 3 \, O_2 (g) \to 2 \, Fe_2O_3 \, (s) \] Here, \(Fe\) (iron) and \(O_2\) (oxygen) are the reactants, while \(Fe_2O_3\) (iron oxide) is the product. This equation helps us understand the stoichiometry of the reaction, which tells us the proportion of the reactants and the products involved in the reaction. In conclusion, the reactants in this reaction are iron (Fe) and oxygen (O₂), and the product is iron oxide (Fe₂O₃).

Key Concepts

Reactants and Products

Understanding the chemistry involved when substances interact requires a basic knowledge of reactants and products. Reactants are the starting materials in a chemical reaction—the substances which undergo a change to create new substances. In our specific example, the rust formation process begins with iron (Fe) and oxygen (O₂) as reactants.

Products, on the other hand, are the new substances formed as a result of a chemical reaction. Rust, chemically known as iron oxide (Fe₂O₃), is the product of the aforementioned reactants. To effectively analyze chemical reactions, it's crucial to identify the reactants and products correctly, which lays the foundation for further study like balancing equations and calculating stoichiometry.

Balancing Chemical Equations

The law of conservation of mass dictates that mass can neither be created nor destroyed in a chemical reaction, which means that the number of atoms of each element must be the same in the reactants and products. Balancing a chemical equation is the process of ensuring this balance. For the rusting reaction, the balanced chemical equation is: \[ 4 \, Fe \, (s) + 3 \, O_2 (g) \to 2 \, Fe_2O_3 \, (s) \]In this equation, there are four iron atoms and three diatomic oxygen molecules on the reactant side, resulting in two molecules of iron oxide, each consisting of two iron atoms and three oxygen atoms. To learn to balance equations well, one must practice recognizing the number of atoms of each element on both sides of the equation and adjusting coefficients to maintain balance.

Stoichiometry

Stoichiometry is a section of chemistry that involves calculating the amounts of reactants and products in chemical reactions. It rests on the quantitative relationship between the elements and compounds as described in a balanced chemical equation. Referring back to our example, \[ 4Fe + 3O_2 \to 2Fe_2O_3 \]the coefficients of the equation indicate the ratio of moles of each reactant used and product formed. Stoichiometry allows us to predict the amount of iron needed to react fully with a given amount of oxygen and vice versa. It also helps in understanding the concept of limiting reactants—the substance that will be fully consumed first in the reaction, thus limiting the amount of product that can be formed. Grasping stoichiometry is pivotal in fields such as medicine, engineering, and environmental science where precise chemical composition is essential.