Problem 24 - Chemistry: An Atoms-Focused Approach

Question

Nitrogen oxides such as \(\mathrm{N}_{2} \mathrm{O}\) and \(\mathrm{N}_{2} \mathrm{O}_{5}\) are present in the air in low concentrations, in part because of their reactivity. Write balanced chemical equations for the following reactions: a. The conversion of \(\mathrm{N}_{2} \mathrm{O}\) to \(\mathrm{NO}_{2}\) in the presence of oxygen b. The decomposition of \(\mathrm{N}_{2} \mathrm{O}_{5}\) to \(\mathrm{NO}_{2}\) and \(\mathrm{O}_{2}\)

Step-by-Step Solution

Answer

Question: Write the balanced chemical equations for the following reactions: a. Conversion of N₂O to NO₂ in the presence of oxygen. b. Decomposition of N₂O₅ to NO₂ and O₂. Answer: a. 2N₂O + O₂ → 4NO₂ b. 2N₂O₅ → 4NO₂ + O₂

Step 1: a. Conversion of N₂O to NO₂ in the presence of oxygen

First, let's identify the reactants and products for this reaction. We have N₂O reacting with O₂ to form NO₂. Now, we need to balance the equation by adjusting the stoichiometric coefficients. The unbalanced equation is: N₂O + O₂ → NO₂ To balance the equation, we can start by balancing the nitrogen atoms. Since there are 2 nitrogen atoms on both sides, they are already balanced. Next, we balance the oxygen atoms. We can do this by adding a coefficient of 2 in front of NO₂. Now we have: N₂O + O₂ → 2NO₂ However, we still have 4 oxygen atoms on the product side and only 3 on the reactant side. To balance the equation, we need to multiply the N₂O by 2: 2N₂O + O₂ → 4NO₂ Now the equation is balanced with 4 nitrogen atoms and 6 oxygen atoms on both sides.

Step 2: b. Decomposition of N₂O₅ to NO₂ and O₂

For this reaction, we have N₂O₅ decomposing into NO₂ and O₂. First, let's write down the unbalanced equation: N₂O₅ → NO₂ + O₂ To balance the equation, we can start by balancing the nitrogen atoms. Since there are 2 nitrogen atoms on the reactant side, we need to multiply NO₂ by 2: N₂O₅ → 2NO₂ + O₂ Now we have 4 oxygen atoms on the product side but 5 on the reactant side. To balance the equation, we can simply multiply O₂ by 1/2: N₂O₅ → 2NO₂ + 1/2O₂ Now the equation is balanced with 2 nitrogen atoms and 5 oxygen atoms on both sides. Normally, we do not use fractions in balanced chemical equations, so we can multiply the whole equation by 2 to eliminate the fraction: 2N₂O₅ → 4NO₂ + O₂ Now we have a balanced equation with whole number coefficients.

Key Concepts

Nitrogen Oxides

Nitrogen oxides are a group of gases that contain nitrogen and oxygen. These gases, which include - dinitrogen monoxide (\( \mathrm{N}_{2} \mathrm{O} \)), also known as laughing gas, and - dinitrogen pentoxide (\( \mathrm{N}_{2} \mathrm{O}_{5} \)), play important roles in atmospheric chemistry.

Nitrogen oxides can come from both man-made sources, like vehicle engines and industrial processes, and natural sources, such as lightning and bacteria in soil.

Due to their reactivity, these compounds are usually found in low concentrations in the air. When nitrogen oxides interact with water, oxygen, or other chemicals, they can create pollutants like \( \mathrm{NO}_{2} \), which contribute to smog and acid rain.

Understanding how these gases react requires knowledge of chemical reactions and the balancing of chemical equations, as these reactions influence environmental and human health.

Stoichiometry

Stoichiometry is the aspect of chemistry that deals with measuring and calculating the quantities of reactants and products in chemical reactions.

In the process of balancing chemical equations, stoichiometry ensures that the same number of atoms for each element is present on both sides of a reaction. This requires using coefficients to adjust the amounts of chemicals involved without changing their identities.

For example, when balancing the conversion of \( \mathrm{N}_{2} \mathrm{O} \) to \( \mathrm{NO}_{2} \), we align the number of nitrogen and oxygen atoms on both sides. This guarantees that no atoms are lost or gained, representing the conservation of mass.

Stoichiometry also helps predict the amounts of products formed from given reactants, enabling scientists and engineers to scale reactions for practical uses in industry and research.

Chemical Reactions

Chemical reactions are processes in which substances, known as reactants, transform into different substances called products.

These transformations occur through the breaking and forming of chemical bonds. A balanced chemical reaction provides a clear description of what happens during this transformation. It specifies the reactants and products along with their respective amounts.

For instance, in the reaction where \( \mathrm{N}_{2} \mathrm{O} \) reacts with \( \mathrm{O}_{2} \) to produce \( \mathrm{NO}_{2} \), the chemical reaction is depicted as:

• Reactants: \( 2\mathrm{N}_{2} \mathrm{O} + \mathrm{O}_{2} \)
• Products: \( 4\mathrm{NO}_{2} \)

This equation is balanced, meaning the number of each type of atom is equal on both sides of the equation. This balance is crucial for accurately understanding and applying chemical processes in various contexts, including environmental science.

Decomposition Reactions

Decomposition reactions are a type of chemical reaction where one compound breaks down into two or more simpler substances.

This type often involves the application of heat, electricity, or another form of energy to break the chemical bonds within a compound. A classic example is the decomposition of \( \mathrm{N}_{2} \mathrm{O}_{5} \) into \( \mathrm{NO}_{2} \) and \( \mathrm{O}_{2} \).

• Decomposition reaction: \( 2\mathrm{N}_{2} \mathrm{O}_{5} \rightarrow 4\mathrm{NO}_{2} + \mathrm{O}_{2} \)

Here, two molecules of \( \mathrm{N}_{2} \mathrm{O}_{5} \) break down to form four molecules of \( \mathrm{NO}_{2} \) and one molecule of \( \mathrm{O}_{2} \) when energy is applied.

Decomposition reactions are vital in various industries and environmental processes. They help in wastewater treatment, recycling, and even energy production. Understanding these reactions provides insights into how materials are transformed, which is essential for effective chemical management and innovation.