Chapter 7: Problem 61
By now, you are familiar with enough chemical compounds to begin to write your own chemical reaction equations. Write two examples of what we mean by a combustion reaction.
Short Answer
Expert verified
Two examples of combustion reactions are:
1. Combustion of methane:
\(CH_{4} + 2O_{2} -> CO_{2} + 2H_{2}O\)
2. Combustion of propane:
\(C_{3}H_{8} + 5O_{2} -> 3CO_{2} + 4H_{2}O\)
Step by step solution
01
Identify the reactants
Methane (CH4) is a simple hydrocarbon that we will use for our first combustion reaction. The other reactant is oxygen gas (O2).
02
Write the unbalanced equation
Write the reactants and products in the equation without balancing them:
\(CH_{4} + O_{2} -> CO_{2} + H_{2}O\)
03
Balance the equation
To balance the equation, we need to ensure that the number of atoms of each element is equal on both sides of the equation. In this case, we need to adjust the amounts of oxygen and water in the reaction:
\(CH_{4} + 2O_{2} -> CO_{2} + 2H_{2}O\)
Now, there are four hydrogen atoms and four oxygen atoms on each side of the equation, and it is balanced.
#Example 2: Combustion of propane#
04
Identify the reactants
Propane (C3H8) is another hydrocarbon that we will use for our second combustion reaction. The other reactant is again oxygen gas (O2).
05
Write the unbalanced equation
Write the reactants and products in the equation without balancing them:
\(C_{3}H_{8} + O_{2} -> CO_{2} + H_{2}O\)
06
Balance the equation
To balance the equation, we need to ensure that the number of atoms of each element is equal on both sides of the equation. In this case, we need to adjust the amounts of carbon dioxide, oxygen, and water in the reaction:
\(C_{3}H_{8} + 5O_{2} -> 3CO_{2} + 4H_{2}O\)
Now, there are eight hydrogen atoms, ten oxygen atoms, and three carbon atoms on each side of the equation, and it is balanced.
These examples demonstrate two different combustion reactions: the combustion of methane and the combustion of propane.
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Key Concepts
These are the key concepts you need to understand to accurately answer the question.
Chemical Compounds
At the heart of understanding chemistry is familiarizing oneself with chemical compounds, which are substances formed when two or more elements are chemically joined together. Each compound has a unique composition represented by a chemical formula, indicating the types and numbers of atoms involved. In combustion reactions, for instance, we deal with hydrocarbons like methane (\( CH_{4} \) and propane (\( C_{3}H_{8} \) which combine with oxygen gas (\( O_{2} \) to produce carbon dioxide (\( CO_{2} \) and water (\( H_{2}O \) as shown in the exercise solutions.
Hydrocarbons are mainly composed of hydrogen and carbon and are crucial due to their role as fuels. The diversity of chemical compounds is vast, ranging from the simplicity of diatomic molecules like oxygen to the complexity of large polymers. Learning to identify and understand these compounds sets the foundation for exploring their reactive behaviors in processes such as combustion.
Hydrocarbons are mainly composed of hydrogen and carbon and are crucial due to their role as fuels. The diversity of chemical compounds is vast, ranging from the simplicity of diatomic molecules like oxygen to the complexity of large polymers. Learning to identify and understand these compounds sets the foundation for exploring their reactive behaviors in processes such as combustion.
Balancing Chemical Equations
Balancing chemical equations is a systematic process we use to respect the Law of Conservation of Mass, which states that in a closed system, mass cannot be created or destroyed. This principle is crucial as it guides us in ensuring that an equal number of each type of atom appears on both the reactant and product sides of a chemical equation.
Begin with an unbalanced equation, as was done in the methane combustion example: \(CH_{4} + O_{2} -> CO_{2} + H_{2}O\). It is clear that the oxygen atoms are not balanced. By adding coefficients in front of the compounds, like the '2' in front of \(O_{2}\) and \(H_{2}O\), we maintain the balance of atoms throughout the reaction, fulfilling the requirement that the total number of atoms for each element must remain constant. This method is pivotal for predicting the quantities of reactants needed and products formed in a chemical reaction.
The same approach applies when we balance the propane combustion reaction, resulting in the equation \(C_{3}H_{8} + 5O_{2} -> 3CO_{2} + 4H_{2}O\). Essentially, balancing equations does not only satisfy academic exercises but is also integral in real-world applications such as pharmaceutical synthesis and environmental engineering.
Begin with an unbalanced equation, as was done in the methane combustion example: \(CH_{4} + O_{2} -> CO_{2} + H_{2}O\). It is clear that the oxygen atoms are not balanced. By adding coefficients in front of the compounds, like the '2' in front of \(O_{2}\) and \(H_{2}O\), we maintain the balance of atoms throughout the reaction, fulfilling the requirement that the total number of atoms for each element must remain constant. This method is pivotal for predicting the quantities of reactants needed and products formed in a chemical reaction.
The same approach applies when we balance the propane combustion reaction, resulting in the equation \(C_{3}H_{8} + 5O_{2} -> 3CO_{2} + 4H_{2}O\). Essentially, balancing equations does not only satisfy academic exercises but is also integral in real-world applications such as pharmaceutical synthesis and environmental engineering.
Hydrocarbons Combustion
The combustion of hydrocarbons is a type of chemical reaction that's critical to modern society, especially for the generation of energy. When a hydrocarbon burns in the presence of oxygen, it releases energy in the form of heat and light, while producing carbon dioxide and water as by-products. This exothermic process is articulated in the balanced equations of methane and propane presented in the exercise.
In the case of methane combustion, the balanced equation \(CH_{4} + 2O_{2} -> CO_{2} + 2H_{2}O\) demonstrates that one methane molecule reacts with two oxygen molecules, and the result is one carbon dioxide molecule and two water molecules. Similarly, for propane combustion, the equation \(C_{3}H_{8} + 5O_{2} -> 3CO_{2} + 4H_{2}O\) shows that each propane molecule reacts with five oxygen molecules, yielding three molecules of carbon dioxide and four of water.
Understanding the combustion of hydrocarbons is also essential from an environmental perspective, as the carbon dioxide produced contributes to the greenhouse effect. By exploring these reactions, students not only become adept at writing and balancing chemical equations but also gain appreciation for the broader implications of such chemical processes on energy production and environmental health.
In the case of methane combustion, the balanced equation \(CH_{4} + 2O_{2} -> CO_{2} + 2H_{2}O\) demonstrates that one methane molecule reacts with two oxygen molecules, and the result is one carbon dioxide molecule and two water molecules. Similarly, for propane combustion, the equation \(C_{3}H_{8} + 5O_{2} -> 3CO_{2} + 4H_{2}O\) shows that each propane molecule reacts with five oxygen molecules, yielding three molecules of carbon dioxide and four of water.
Understanding the combustion of hydrocarbons is also essential from an environmental perspective, as the carbon dioxide produced contributes to the greenhouse effect. By exploring these reactions, students not only become adept at writing and balancing chemical equations but also gain appreciation for the broader implications of such chemical processes on energy production and environmental health.
