Question

In the chapter, we saw the combustion reaction for methane. This was actually a complete combustion reaction because carbon ended up as carbon dioxide. If the same reaction is carried out where the oxygen supply is limited, incomplete combustion takes place, yielding toxic carbon monoxide, CO, instead of \(\mathrm{CO}_{2}\). Write the balanced reaction for the incomplete combustion of methane. Make sure it is balanced.

Short answer

The balanced equation for the incomplete combustion of methane is: \(CH_4 + \frac{3}{2}O_2 \rightarrow CO + 2H_2O\).

Step-by-step solution

Write down the incomplete combustion equation

The incomplete combustion of methane involves the reaction between methane (CH4) and oxygen (O2) to give carbon monoxide (CO) and water (H2O). The unbalanced equation is: CH4 + O2 -> CO + H2O

Balance the equation

To balance this equation, we need to ensure that we have equal amounts of each element on both sides of the reaction. 1. Carbon (C) has one atom on either side, so it is already balanced. 2. Hydrogen (H) has 4 atoms on the left side and 2 atoms on the right side. To balance this, we need to multiply the water (H2O) by 2. CH4 + O2 -> CO + 2H2O 3. Now, we have 2 oxygen atoms on the left side and 3 oxygen atoms on the right side (1 from CO and 2 from 2H2O). In order to balance the oxygen atoms, we can multiply the oxygen (O2) by 3/2. So, the balanced equation for incomplete combustion of methane becomes: CH4 + 3/2O2 -> CO + 2H2O

Key concepts

Incomplete Combustion

Incomplete combustion occurs when there is not enough oxygen available for a fuel, such as methane, to react completely. Instead of forming carbon dioxide (CO2), which is the end product in complete combustion, the reaction yields carbon monoxide (CO), a toxic gas, along with water (H2O). This kind of reaction is common in scenarios where oxygen is limited, such as in car engines or poorly ventilated spaces.

During incomplete combustion, the following points should be noted:

• Lack of sufficient oxygen leads to the formation of harmful gases.
• Incomplete combustion is less efficient and releases less energy compared to complete combustion.
• The presence of carbon monoxide can be dangerous and poses health risks.

In industrial and household settings, ensuring complete combustion by providing an adequate air supply can minimize the release of toxic gases.

Methane Combustion

Methane combustion is an example of a combustion reaction where methane gas (CH4) reacts with oxygen (O2) to produce heat and other products. There are two primary types of methane combustion reactions: complete and incomplete.

In **complete methane combustion**, an ample supply of oxygen ensures that methane burns entirely to produce carbon dioxide (CO2) and water (H2O), releasing a significant amount of energy. The balanced equation for this reaction is:\[\text{CH}_4 + 2\text{O}_2 \rightarrow \text{CO}_2 + 2\text{H}_2\text{O}\]However, when **incomplete combustion** occurs, methane and oxygen react instead to form carbon monoxide (CO) and water due to the limited supply of oxygen. This is expressed in the balanced equation as:\[\text{CH}_4 + \dfrac{3}{2}\text{O}_2 \rightarrow \text{CO} + 2\text{H}_2\text{O}\]The incomplete combustion is a concern because of the reduced energy output and the production of carbon monoxide, which is highly toxic.

Chemical Reactions

Chemical reactions involve the transformation of reactants into products. These transformations can include the change in chemical structure and energy. Understanding the balancing of a chemical reaction is crucial for accurately representing the quantity relationships between substances in the reaction. A balanced chemical equation ensures that atoms are neither created nor destroyed during the reaction.

In general terms:

• Start by writing the unbalanced equation with the chemical formulas of reactants and products.
• List the number of each atom present in reactants and products to guide the balancing process.
• Use coefficients to adjust the number of molecules until the number of atoms for each element is the same on both sides of the equation.
  Use multiplication or fractions where necessary.

Balancing chemical equations allows scientists and engineers to predict product yields and reactant needs, which is fundamental in planning chemical processes and safety assessments. It's essential in fields like energy production, environmental science, and materials science.