Question

Write a balanced equation for the thermal decomposition of aluminum nitrate to form aluminum oxide, nitrogen dioxide, and oxygen gas.

Short answer

2Al(NO₃)₃ → Al₂O₃ + 6NO₂ + 3O₂

Step-by-step solution

Identify the Reactants and Products

The reactant is aluminum nitrate, which decomposes to form aluminum oxide, nitrogen dioxide, and oxygen gas as products.

Write the Unbalanced Equation

Express the decomposition reaction using the chemical formulas. Aluminum nitrate is represented as \( \text{Al(NO}_3)_3 \), aluminum oxide as \( \text{Al}_2\text{O}_3 \), nitrogen dioxide as \( \text{NO}_2 \), and oxygen gas as \( \text{O}_2 \). The unbalanced equation is:\[ \text{Al(NO}_3)_3 \rightarrow \text{Al}_2\text{O}_3 + \text{NO}_2 + \text{O}_2 \]

Balance Aluminum Atoms

Balance the aluminum atoms by ensuring the same number of aluminum atoms appear on both sides. As you have 2 aluminum atoms in \( \text{Al}_2\text{O}_3 \), place a coefficient of 2 in front of \( \text{Al(NO}_3)_3 \):\[ 2\text{Al(NO}_3)_3 \rightarrow \text{Al}_2\text{O}_3 + \text{NO}_2 + \text{O}_2 \]

Balance Nitrogen Atoms

Calculate the number of nitrogen atoms and balance them. There are 6 nitrogen atoms in 2 moles of \( \text{Al(NO}_3)_3 \). Therefore, place a 6 in front of \( \text{NO}_2 \):\[ 2\text{Al(NO}_3)_3 \rightarrow \text{Al}_2\text{O}_3 + 6\text{NO}_2 + \text{O}_2 \]

Balance Oxygen Atoms

Check the total number of oxygen atoms. There are 18 oxygen atoms in 2 moles of \( \text{Al(NO}_3)_3 \), 9 of which are used in \( \text{AL}_2\text{O}_3 \), leaving 9 for \( \text{NO}_2 \) and \( \text{O}_2 \). Add a 3 in front of \( \text{O}_2 \) to balance the remaining 6 oxygen atoms:\[ 2\text{Al(NO}_3)_3 \rightarrow \text{Al}_2\text{O}_3 + 6\text{NO}_2 + 3\text{O}_2 \]

Confirm the Balanced Equation

Verify each type of atom is balanced on both sides. It should be confirmed that there are 2 Al, 6 N, and 18 O atoms on both sides of the equation, confirming that the balanced equation is:\[ 2\text{Al(NO}_3)_3 \rightarrow \text{Al}_2\text{O}_3 + 6\text{NO}_2 + 3\text{O}_2 \]

Key concepts

Aluminum Nitrate

Aluminum nitrate is a chemical compound formed by the elements aluminum, nitrogen, and oxygen. Its formula is \( \text{Al(NO}_3)_3 \). The compound is commonly used in laboratory and industrial processes.

When aluminum nitrate is subjected to heat, it undergoes a process known as thermal decomposition, breaking down into simpler substances.

• Aluminum nitrate is quite soluble in water, making it useful in aqueous solutions.
• In its solid form, aluminum nitrate appears as a white crystalline substance.
• Like other nitrates, it can act as an oxidizing agent, facilitating certain chemical reactions.

Understanding the properties and behavior of aluminum nitrate is crucial for predicting its reactions with other substances.

Thermal Decomposition

Thermal decomposition is a chemical reaction where a compound breaks down into smaller components when heated. This type of reaction is endothermic, meaning it absorbs heat from the surroundings.

When aluminum nitrate undergoes thermal decomposition, it forms aluminum oxide, nitrogen dioxide, and oxygen gas. Understanding this process is essential for various applications in chemistry.

• The substance being decomposed absorbs energy which causes the bonds holding its atoms together to break.
• Decomposition reactions are often used to extract metals from their ores and are fundamental to the production of many materials.
• Factors such as temperature and pressure can significantly affect the decomposition process.

Recognizing the signs of thermal decomposition helps in controlling reactions effectively.

Aluminum Oxide

Aluminum oxide, also known as alumina, is a compound essential to many industrial processes. Its chemical formula is \( \text{Al}_2\text{O}_3 \). This white, crystalline powder is highly durable and resistant to electrical insulation.

The production of aluminum oxide from the decomposition of aluminum nitrate showcases its importance.

• Aluminum oxide is noted for its strength and hardness, making it a valuable material in ceramics and abrasives.
• It is widely used as a catalyst in chemical reactions and is crucial in the production of aluminum metal via the Bayer process.
• Furthermore, it is a major component used in the formulation of many medical and cosmetic products.

Its utility spans various industries, emphasizing its role in material science.

Nitrogen Dioxide

Nitrogen dioxide is a reddish-brown gas with a strong odor, characterized by the chemical formula \( \text{NO}_2 \). It is an intermediate product in the thermal decomposition of aluminum nitrate.

As a significant air pollutant, it is essential to understand its properties and effects.

• Nitrogen dioxide plays a role in atmospheric reactions, contributing to the formation of smog and acid rain.
• It is also associated with respiratory problems, underscoring the importance of monitoring and regulating emissions.
• Despite its environmental impact, it serves as an oxidizer in industrial chemical reactions.

Understanding nitrogen dioxide's chemistry helps to mitigate its adverse environmental effects while leveraging its industrial applications.

Oxygen Gas

Oxygen gas, represented by the formula \( \text{O}_2 \), is a vital molecule in many chemical reactions, including the decomposition of aluminum nitrate. It is a colorless, odorless gas that is crucial for combustion and life processes.

• Oxygen is an abundant element essential for life on Earth, facilitating processes like respiration in aerobic organisms.
• In the context of thermal decomposition, oxygen often serves as a reactant or a product, influencing the reaction dynamics.
• This gas is used in various applications, from fuel burning to medical therapies, showing its universal relevance.

Learning how oxygen interacts and the role it plays in reactions aids in understanding broader chemical processes.