Problem 113 - Chemistry Matter and Change

Question

Write the skeleton equation and the balanced chemical equation for the reaction between iron and chlorine.

Step-by-Step Solution

Answer

The skeleton equation for the reaction between iron (Fe) and chlorine (Cl₂) is: Fe + Cl₂ → FeCl₃ To balance the chemical equation, we adjust the coefficients: 2Fe + 3Cl₂ → 2FeCl₃

Step 1: Write the Skeleton Equation

To write the skeleton equation, we need to identify the reactants and products in the reaction between iron and chlorine. Iron is represented by the symbol Fe, and chlorine is represented by the symbol Cl₂ (chlorine exists as a diatomic molecule). When iron reacts with chlorine, it forms iron(III) chloride, which has the formula FeCl₃. So, the skeleton equation is written as follows: Fe + Cl₂ → FeCl₃

Step 2: Balance the Chemical Equation

We need to make sure that the number of atoms of each element is equal on both sides of the equation. Currently, there is one iron atom on each side of the equation. However, there are two chlorine atoms in the diatomic chlorine molecule on the left side of the equation and three chlorine atoms in iron(III) chloride on the right side. To balance the chlorine atoms, we need to multiply both reactants and products by appropriate coefficients. In this case, we can multiply Cl₂ by 3 and FeCl₃ by 2: 2Fe + 3Cl₂ → 2FeCl₃ Now the equation is balanced, as there are 2 iron and 6 chlorine atoms on both sides of the equation. So, the balanced chemical equation for the reaction between iron and chlorine is: 2Fe + 3Cl₂ → 2FeCl₃

Key Concepts

Chemical Reactions

Chemical reactions are processes in which substances, known as reactants, transform into different substances called products. This transformation occurs through the breaking and forming of chemical bonds. An example of a chemical reaction is the reaction between iron (Fe) and chlorine (Cl₂) to form iron(III) chloride (FeCl₃).

During this reaction, Fe atoms react with Cl₂ molecules through a combination reaction, leading to the production of a new compound. Understanding the nature of these reactions is crucial as they are the foundation of chemistry itself. The reactants and products involve elements and compounds which obey the law of conservation of mass, meaning the number of atoms of each element must remain constant before and after the reaction.

Stoichiometry

Stoichiometry is the aspect of chemistry that deals with the quantitative relationships between reactants and products in a chemical reaction. The goal is to have the same number of atoms of each element on both sides of the chemical equation, adhering to the law of conservation of mass.

In the example of iron reacting with chlorine, the process of stoichiometry involves figuring out the right coefficients to balance the equation. We do this by ensuring that the number of atoms for each element is equal on both the reactant and product sides. By introducing coefficients, 2 before Fe and 3 before Cl₂, we account for 2 atoms of iron and 6 atoms of chlorine on both sides, successfully balancing the equation.

Chemical Formulas

Chemical formulas represent the composition of chemical substances using symbols and numerical subscripts. They indicate the types of atoms present and the exact number of atoms of each element in a molecule. For instance, in the balanced chemical equation 2Fe + 3Cl₂ → 2FeCl₃, Fe symbolizes iron, Cl₂ represents a molecule of chlorine with two atoms due to its diatomic nature, and FeCl₃ stands for iron(III) chloride.

Understanding chemical formulas is vital for comprehending the substances involved in chemical reactions and allows chemists to communicate universally about chemical compounds. This convention helps in predicting the products of reactions and the quantities needed for reactions to occur fully.