What is wrong with the following procedure for obtaining magnesium?$$\begin{aligned}& \mathrm{MgCO}_{3} \longrightarrow \mathrm{MgO}(s)+\mathrm{CO}_{2}(g) \\\\\mathrm{MgO}(s)+\mathrm{CO}(g) & \longrightarrow \mathrm{Mg}(s)+\mathrm{CO}_{2}(g)\end{aligned}$$

Decomposition reactions are chemical processes where a single compound breaks down into two or more simpler substances. An educational example of this type is the breakdown of Magnesium Carbonate (\( \text{MgCO}_3 \)) into Magnesium Oxide (\( \text{MgO} \)) and Carbon Dioxide (\( \text{CO}_2 \)). These reactions typically occur under specific conditions, often requiring heat, known as thermolysis.

In the classroom, students are taught that during decomposition, the original compound loses its characteristics as new substances with distinct properties form. Understanding the conditions that lead to successful decomposition reactions, such as temperature and pressure, helps students predict the outcome of chemical reactions.It's crucial for them to note that for extraction purposes, identifying the correct compound for decomposition and the adequate conditions are of utmost importance to avoid errors.

Energy Considerations in Reactions

A pertinent concept in chemistry is the thermodynamic feasibility of a reaction, which answers the question: Will the reaction occur under given conditions? This depends on factors like energy changes, reaction kinetics, and entropy.

In a problem where magnesium extraction is concerned, despite a reaction being theoretically possible, it must also be energetically favorable – meaning it must release energy (exothermic) or require less energy than made available by the system. For students, understanding that every reaction strives towards a lower energy state can assist in grasping why certain extractions or reactions may or may not occur in the laboratory or industry.

Unchanging Energy in Chemical Processes

The law of conservation of energy is a foundational principle in physics and chemistry which states that energy cannot be created or destroyed, only transferred or transformed from one form to another. This principle applies strictly to chemical reactions, including those involving Magnesium Oxide (\( \text{MgO} \)).

In discussing the extraction of magnesium, the application of the energy conservation law highlights how reactions must balance energetically. Students should consider whether the energy produced by a reaction can sufficiently account for another simultaneous reaction. If a procedure suggests that less energy is required to form a product than is released, this could indicate an error, as seen in the erroneous textbook extraction procedure for magnesium.

Challenges with Reacting Magnesium Oxide

Magnesium Oxide (\( \text{MgO} \)) is known for its high melting point and relative stability, which makes it less reactive under normal conditions. These properties are relevant when discussing its reactivity concerning other substances like Carbon Monoxide (\( \text{CO} \)).

Students learning about reactivity should understand that attempts to react \text{MgO} with \text{CO} must consider whether the reaction partners are suited for each other in terms of their reactivity and energy requirements. The educational focus should be on the fact that reactivity is not just about whether a reaction can occur, but also about the conditions under which it proceeds feasibly. This understanding can prevent misconceptions about the ease of extracting elements like magnesium from their oxides.