Question

If a hydrocarbon is combined with enough halogen, all the \(\mathrm{H}\) atoms will eventually be substituted with that halogen atom. Write the balanced chemical reaction between ethane and excess chlorine.

Short answer

The balanced equation is \( \text{C}_2\text{H}_6 + 3\text{Cl}_2 \rightarrow \text{C}_2\text{Cl}_6 + 6\text{HCl} \).

Step-by-step solution

Identify the Reactants

First, identify the reactants in this chemical equation. We have ethane, a hydrocarbon with the formula \( \text{C}_2\text{H}_6 \), and chlorine, which is represented as \( \text{Cl}_2 \).

Predict the Products

When ethane reacts with excess chlorine, each hydrogen atom in ethane can be replaced by a chlorine atom, forming 1,2,2,2-tetrachloroethane \( \text{C}_2\text{Cl}_6 \), along with hydrogen chloride \( \text{HCl} \) as a byproduct.

Write the Skeleton Equation

Write the unbalanced skeleton chemical equation: \[ \text{C}_2\text{H}_6 + \text{Cl}_2 \rightarrow \text{C}_2\text{Cl}_6 + \text{HCl} \].

Balance the Chlorine Atoms

Count the number of chlorine atoms on both sides. Ethane initially has no chlorines, while the product \( \text{C}_2\text{Cl}_6 \) contains 6. Therefore, we need to ensure chlorine is in excess by balancing: \[ \text{C}_2\text{H}_6 + 3\text{Cl}_2 \rightarrow \text{C}_2\text{Cl}_6 + 6\text{HCl} \].

Balance the Hydrogen Atoms

Verify that the hydrogen atoms are balanced. There are 6 hydrogen atoms in \( \text{C}_2\text{H}_6 \) and each \( \text{HCl} \) contains 1 hydrogen atom, so we need 6 \( \text{HCl} \) molecules to balance hydrogen, which we already have in the balanced equation.

Confirm the Balanced Equation

Double-check all elements: \( \text{C} \), \( \text{H} \), and \( \text{Cl} \) atoms are equal on both sides. The balanced equation is: \[ \text{C}_2\text{H}_6 + 3\text{Cl}_2 \rightarrow \text{C}_2\text{Cl}_6 + 6\text{HCl} \].

Key concepts

Chemical Reactions

In the realm of chemistry, reactions are fundamental processes by which substances, known as reactants, are transformed into new substances, called products. Each chemical reaction is associated with a change in chemical bonds and is represented by a chemical equation. Take for instance, the reaction between ethane and chlorine. Ethane, a hydrocarbon, combines with chlorine (a halogen) to form new products. This type of reaction highlights how molecules interact and change during chemical processes. These reactions are influenced by various factors including the nature of the reactants and the conditions under which the reaction occurs. Understanding the basic principles of chemical reactions is vital, not only to predict the outcome but also to implement it efficiently in scientific and industrial applications.

Balancing Equations

Balancing chemical equations is a crucial step in describing a chemical reaction. It involves making sure that the number of each type of atom is equal on both sides of the equation. This reflects the principle of the conservation of mass, meaning that matter cannot be created or destroyed in a chemical reaction.
In our example, starting with the skeleton equation of the reaction between ethane \( \text{C}_2\text{H}_6 \) and chlorine \( \text{Cl}_2 \), we must balance all elements. Initially, the chlorine atoms are not balanced. The product \( \text{C}_2\text{Cl}_6 \) contains 6 chlorine atoms, so we need 3 diatomic chlorine molecules on the reactant side. After addressing chlorine, we count hydrogen atoms to ensure they are balanced as well, ensuring the equation is accurate and respects the conservation of atoms.

Reaction Products

The products in a chemical reaction are the substances formed from the reactants after a chemical change. In the context of hydrocarbon halogenation, the primary product we get is a new halogenated compound, alongside any side products that might be produced.
For ethane reacting with chlorine, the main product is 1,2,2,2-tetrachloroethane \( \text{C}_2\text{Cl}_6 \), with hydrogen chloride \( \text{HCl} \) as a byproduct. The formation of these products can be understood better by looking at the process of substitution, where hydrogen atoms in the hydrocarbon are replaced by chlorine atoms. Each chlorine molecule provides 2 chlorine atoms, meaning it can replace 2 hydrogen atoms in the ethane molecule, thus dramatically changing the chemical structure and properties of the original substance. Fully understanding reaction products allows scientists to predict the behavior and characteristics of the resulting compounds, which can be pivotal in developing new materials and chemical processes.