Question

The Group 2 metals \((\mathrm{Ba}, \mathrm{Ca}, \mathrm{Sr})\) can be produced in the elemental state by the reaction of their oxides with aluminum metal at high temperatures, also producing solid aluminum oxide as a byproduct. Write the unbalanced chemical equations for the reactions of barium oxide, calcium oxide, and strontium oxide with aluminum.

Short answer

The unbalanced chemical equations for the reactions of barium oxide, calcium oxide, and strontium oxide with aluminum are: 1. Barium oxide (BaO) and aluminum (Al): \(BaO + Al \rightarrow Ba + Al_2O_3\) 2. Calcium oxide (CaO) and aluminum (Al): \(CaO + Al \rightarrow Ca + Al_2O_3\) 3. Strontium oxide (SrO) and aluminum (Al): \(SrO + Al \rightarrow Sr + Al_2O_3\)

Step-by-step solution

Write the unbalanced chemical equation for the reaction of barium oxide with aluminum.

Barium oxide (BaO) reacts with aluminum (Al) to produce barium (Ba) and aluminum oxide (Al2O3). The unbalanced chemical equation is: \(BaO + Al \rightarrow Ba + Al_2O_3\)

Write the unbalanced chemical equation for the reaction of calcium oxide with aluminum.

Calcium oxide (CaO) reacts with aluminum (Al) to produce calcium (Ca) and aluminum oxide (Al2O3). The unbalanced chemical equation is: \(CaO + Al \rightarrow Ca + Al_2O_3\)

Write the unbalanced chemical equation for the reaction of strontium oxide with aluminum.

Strontium oxide (SrO) reacts with aluminum (Al) to produce strontium (Sr) and aluminum oxide (Al2O3). The unbalanced chemical equation is: \(SrO + Al \rightarrow Sr + Al_2O_3\) Now, the unbalanced chemical equations for the reactions of barium oxide, calcium oxide, and strontium oxide with aluminum are written.

Key concepts

Group 2 Metals

Group 2 metals, also known as alkaline earth metals, include beryllium (Be), magnesium (Mg), calcium (Ca), strontium (Sr), barium (Ba), and radium (Ra). Despite being widespread, these metals are not found free in nature due to their high reactivity; they typically exist combined with other elements in compounds. Calcium, strontium, and barium are particularly relevant when discussing reactions with aluminum.

Group 2 metals are characterized by having two electrons in their outermost energy level, which they tend to lose in order to form cations with a +2 charge. This makes them highly reactive, especially when heated, which is why high temperatures can facilitate their reduction from their oxides to the elemental metal form. Such reactions are often employed in extractive metallurgy to procure the pure metals from their ores.

Understanding the properties of these metals helps us to grasp why they behave as they do in chemical reactions. For instance, their reactivity increases with heavier atoms such as barium, making them viable candidates for reactions with aluminum, a process with important industrial applications.

Reaction with Aluminum

The reaction of Group 2 metal oxides with aluminum is a thermite-like reaction, a process characterized by its exothermic nature. In this reaction, aluminum serves as a reducing agent and is oxidized, while the metal oxide is reduced. As a consequence, a very intense release of heat occurs, producing the metal in its elemental form and solid aluminum oxide (Al2O3) as a byproduct.

When Group 2 metal oxides react with aluminum, the aluminum's propensity to oxidize due to its high affinity for oxygen is a driving force. The process not only yields valuable metals such as barium, calcium, and strontium but also forms aluminum oxide, which itself has various uses, including serving as an abrasive and as a refractory material. As these reactions require high temperatures, they must be conducted under controlled conditions to ensure safety and optimal recovery of the desired metal.

It is crucial for students to recognize that despite aluminum's reaction with different Group 2 metal oxides following a similar pattern, the stoichiometry — that is, the proportion of reactants to products — may differ. Proper understanding of chemical equations is essential for grasping these reactions.

Unbalanced Chemical Equations

In chemistry, writing a chemical equation is a way of representing a chemical reaction using symbols and formulas. An unbalanced chemical equation shows the reactants and products but does not reflect the conservation of atoms, which is a fundamental principle in reactions. In other words, it lacks the proper stoichiometric coefficients that ensure the same number of each type of atom is present on both sides of the equation.

An example of an unbalanced equation is the reaction between barium oxide and aluminum: \(BaO + Al \rightarrow Ba + Al_2O_3\). While the reactants and products are correctly identified, the equation does not account for the conservation of mass, since the aluminum and oxygen atoms are not balanced.

In the process of balancing the equations, students typically add coefficients in front of the chemical formulas to achieve the same number of atoms for each element on both sides. Recognizing the need for balancing is an initial step in solving chemical reactions. Learning to balance equations not only is crucial for understanding chemical reactions but also develops problem-solving skills and a deeper insight into the law of conservation of mass in chemical processes.