Question

9\. Aluminum metal can be used to remove tarnish from silver when the two solid metals are placed in water, according to the following reaction. 3 AgO + 2 Al 3 Ag + Al2O3 This reaction is a I. double-displacement reaction. II. single-displacement reaction. III. redox reaction. IV. combination reaction. A. II only B. I and III C. II and III D. IV only

Short answer

C. II and III

Step-by-step solution

- Identify the Reactants and Products

Start by identifying the reactants (AgO and Al) and the products (Ag and Al2O3) in the given reaction.

- Write the Balanced Chemical Equation

The balanced chemical equation for the reaction is: \[ 3 \text{AgO} + 2 \text{Al} \rightarrow 3 \text{Ag} + \text{Al}_2\text{O}_3 \]

- Determine if it is a Single-Displacement Reaction

In a single-displacement reaction, one element displaces another in a compound. Here, Al displaces Ag from AgO. This indicates it is a single-displacement reaction.

- Determine if it is a Redox Reaction

In a redox reaction, there is a transfer of electrons. Al is oxidized (loses electrons) and AgO is reduced (gains electrons). Thus, it is a redox reaction.

- Determine if it is a Double-Displacement or Combination Reaction

In a double-displacement reaction, two elements or groups replace each other in compounds. In a combination reaction, two or more substances combine to form a single new substance. This reaction doesn't fit either category.

- Conclusion

Since the reaction is both a single-displacement and a redox reaction, choose the option that matches these criteria.

Key concepts

Single-Displacement Reaction

In a single-displacement reaction, one element replaces another in a compound. These reactions generally occur when a more reactive element displaces a less reactive one from its compound.
For example, in the reaction:

• 3 AgO + 2 Al -> 3 Ag + Al2O3
• Al replaces the Ag in AgO, forming Ag and Al₂O₃.

This showcases the nature of single-displacement reactions. They often involve metals reacting with compounds containing other metals.
Understanding which element will be displaced requires knowledge of the reactivity series, a list ranking elements by their reactivity. Aluminum is more reactive than silver, so it can displace silver from silver oxide.
Recognizing these reactions is critical in predicting the products of a chemical reaction and balancing chemical equations correctly.

Redox Reaction

Redox reactions, short for reduction-oxidation reactions, involve the transfer of electrons between substances. One substance is oxidized (loses electrons), while another is reduced (gains electrons).
For the given reaction:

• 3 AgO + 2 Al -> 3 Ag + Al2O3
• Aluminum (Al) is oxidized as it loses electrons:
• 2Al -> 2Al³⁺ + 6e⁻
• Silver oxide (AgO) is reduced as it gains electrons:
• 3AgO + 6e⁻ -> 3Ag + 3O²⁻

Essentially, oxidation and reduction occur simultaneously in these reactions. Because electrons transfer from aluminum to silver oxide, both substances undergo a chemical change.
Understanding redox reactions is essential, as they are fundamental to various chemical processes, including batteries, corrosion, and metabolic pathways in biology.
Recognizing the signs of redox reactions helps in identifying them during chemical analysis and predicting how substances will interact.

Chemical Reactions

Chemical reactions involve the transformation of reactants into products. These processes can often be identified by changes in color, temperature, the formation of a precipitate, or the release of gas. The fundamental types of chemical reactions include:

• Single-Displacement Reactions
• Double-Displacement Reactions
• Combination Reactions
• Decomposition Reactions
• Combustion Reactions

Each type follows specific patterns and involves different changes in bonds and energy.
For example, in the exercise, the reaction between silver oxide and aluminum is a single-displacement reaction. The different types of reactions help chemists categorize and predict how substances will react with each other.
To confirm the type of reaction, it's essential to balance the chemical equation. This ensures the conservation of mass, showing that atoms are neither created nor destroyed during the reaction.
Mastering the types of chemical reactions and their characteristics allows students to understand and predict the outcomes of various chemical processes. Balancing equations is a fundamental skill for ensuring the correct proportions of reactants and products.