Problem 2 - Chemistry and Chemical Reactivity

Question

Write an equation from the following description: reactants are gaseous \(\mathrm{NH}_{3}\) and \(\mathrm{O}_{2},\) products are gaseous \(\mathrm{NO}_{2}\) and liquid \(\mathrm{H}_{2} \mathrm{O},\) and the stoichiometric coefficients are \(4,7,4,\) and \(6,\) respectively.

Step-by-Step Solution

Answer

The chemical equation is \( 4\text{NH}_3 (g) + 7\text{O}_2 (g) \rightarrow 4\text{NO}_2 (g) + 6\text{H}_2O (l) \).

Step 1: Identify Reactants and Products

We identify the reactants as gaseous \( \text{NH}_3 \) and \( \text{O}_2 \), and the products as gaseous \( \text{NO}_2 \) and liquid \( \text{H}_2O \).

Step 2: Assign Stoichiometric Coefficients

According to the problem, the stoichiometric coefficients for \( \text{NH}_3 \), \( \text{O}_2 \), \( \text{NO}_2 \), and \( \text{H}_2O \) are 4, 7, 4, and 6, respectively. These coefficients will represent the number of moles for each reactant and product in the balanced chemical equation.

Step 3: Write the Balanced Chemical Equation

With the identified substances and assigned coefficients, we can write the balanced chemical equation as follows: 4 \( \text{NH}_3 (g) + 7 \text{O}_2 (g) \rightarrow 4 \text{NO}_2 (g) + 6 \text{H}_2O (l) \)

Key Concepts

Stoichiometry

Stoichiometry is a wonderful tool in chemistry that allows us to understand the quantitative relationships in chemical reactions. When dealing with stoichiometry, we're often tackling the problem of determining the correct proportions of reactants and products.
For example, in the exercise above, the stoichiometric coefficients are provided to help balance the chemical equation. These coefficients indicate the number of moles for each substance involved in the reaction.

• The coefficient for ammonia (\( ext{NH}_3 \)) is 4.
• The coefficient for oxygen (\( ext{O}_2 \)) is 7.
• The coefficient for nitrogen dioxide (\( ext{NO}_2 \)) is 4.
• And the coefficient for water (\( ext{H}_2O \)) is 6.

These numbers ensure the law of conservation of mass is satisfied, meaning that the quantity of each element is the same on both sides of the equation. Stoichiometry is crucial not only for balancing equations but also for calculating the amounts of substances needed or produced in a chemical reaction.

Chemical reactions

Chemical reactions are processes that involve the rearrangement of atoms and molecules to form new substances. In the given exercise, the challenge was to write the balanced equation for the reaction between ammonia and oxygen.
A chemical reaction can be influenced by several factors such as temperature, pressure, and concentration. These reactions are often visualized through a chemical equation, where the reactants are listed on the left side and the products on the right, separated by an arrow that signifies the direction of the reaction.
Let's break down the key elements of the example reaction:

• The reactants are gaseous \( ext{NH}_3 \) and \( ext{O}_2 \).
• The products are gaseous \( ext{NO}_2 \) and liquid \( ext{H}_2O \).

The arrow indicates that ammonia and oxygen react to produce nitrogen dioxide and water. Each of the elements behaves according to its chemical properties, forming products that differ from the reactants. Understanding these reactions helps in predicting the behavior of substances under different conditions.

Gaseous reactants and products

Gaseous reactants and products play a significant role in various chemical reactions. Gases have unique properties that distinguish them from solids and liquids, such as their ability to expand and fill a container, and their high compressibility.
In our given equation, both ammonia (\( ext{NH}_3 \)) and oxygen (\( ext{O}_2 \)) are in a gaseous state. They react to produce nitrogen dioxide (\( ext{NO}_2 \)), which also exists as a gas under standard conditions, and water (\( ext{H}_2O \)), which is in a liquid state.
Gaseous reactions often require specific conditions, such as increased pressure or the presence of a catalyst, to proceed effectively. Understanding the nature of gaseous compounds is essential in harnessing these reactions for industrial and laboratory applications.
Balancing chemical equations with gaseous components requires attention to their volumes, temperatures, and pressures, aligning with the principles of stoichiometry to ensure a balanced and successful reaction.