Question

All of the following compounds yield ${\mathrm{O}}_2(\mathrm{g})$ when heated to about $1000\mathrm{K}$ except (a) ${\mathrm{KClO}}_3;$ (b) ${\mathrm{KClO}}_4$ (c) ${\mathrm{N}}_2\mathrm{O};$ (d) ${\mathrm{CaCO}}_3;$ (e) $\mathrm{Pb}{\left({\mathrm{NO}}_3\right)}_2$.

Short answer

The compound that does not yield gaseous Oxygen when heated to approximately 1000 K is ${\mathrm{CaCO}}_3$.

Step-by-step solution

Analyze KClO3

${\mathrm{KClO}}_3$ is Potassium Chlorate. When heated, it decomposes into Potassium Chloride and Oxygen. So, it does yield ${\mathrm{O}}_2(\mathrm{g})$.

Analyze KClO4

${\mathrm{KClO}}_4$ is Potassium Perchlorate. This compound also decomposes into Potassium Chloride and Oxygen gas when heated, hence it also yields ${\mathrm{O}}_2(\mathrm{g})$.

Analyze N2O

${\mathrm{N}}_2\mathrm{O}$ is Nitrous Oxide. Upon heating, it decomposes into Nitrogen gas and Oxygen gas. So, it yields ${\mathrm{O}}_2(\mathrm{g})$ as well.

Analyze CaCO3

${\mathrm{CaCO}}_3$ is Calcium Carbonate. It decomposes into Calcium Oxide and Carbon Dioxide when heated. So, it does not yield ${\mathrm{O}}_2(\mathrm{g})$.

Analyze Pb(NO3)2

$\mathrm{Pb}{\left({\mathrm{NO}}_3\right)}_2$ is Lead Nitrate. This compound decomposes into Lead Oxide, Nitrogen Dioxide, and Oxygen gas when heated. Therefore, it does yield ${\mathrm{O}}_2(\mathrm{g})$.

Key concepts

Potassium Chlorate

Potassium Chlorate, with the chemical formula ${\mathrm{KClO}}_3$, is a fascinating example of a chemical compound that releases oxygen when heated. This reaction is a classic illustration of a decomposition reaction, a type of chemical reaction where one substance breaks down into two or more substances.
Upon heating, Potassium Chlorate undergoes a significant change at temperatures around 1000 K, transforming into Potassium Chloride ($\mathrm{KCl}$) and releasing Oxygen gas (${\mathrm{O}}_2$).
This process is broadly represented by the equation:

$${2\mathrm{KClO}}_3(s)\to 2\mathrm{KCl}(s)+{3\mathrm{O}}_2(g)$$

Key points about Potassium Chlorate decomposition:

• It acts as an oxidizing agent, which means it can donate oxygen to other substances in a reaction.
• The oxygen released is a result of breaking the strong chlorine-oxygen bond in the chlorate ion.
• This decomposition reaction is exothermic, releasing heat in the process.

Understanding this reaction is crucial in fields such as chemistry and environmental science, where the controlled release of oxygen is utilized.

Potassium Perchlorate

Potassium Perchlorate, represented by ${\mathrm{KClO}}_4$, is another compound known for its ability to produce oxygen upon decomposition. When heated, it goes through a decomposition reaction that releases oxygen, similar to Potassium Chlorate.
The decomposition process for Potassium Perchlorate can be summarized by the equation:

$${\mathrm{KClO}}_4(s)\to \mathrm{KCl}(s)+2{\mathrm{O}}_2(g)$$

This equation shows that each molecule of Potassium Perchlorate breaks down to yield Potassium Chloride and 2 molecules of Oxygen gas.

Here are some important aspects:

• Potassium Perchlorate is often used in pyrotechnics and explosives due to its ability to supply oxygen to the burning process.
• The perchlorate ion is more stable than the chlorate ion, which means it requires more energy to decompose, making it less reactive under standard conditions.
• While stable, heating it to decomposition releases a considerable amount of oxygen, making it useful for applications requiring a rapid release of gas.

This decomposition is significant in understanding various industrial processes and safety protocols when handling oxidizing agents.

Calcium Carbonate

Calcium Carbonate, chemically known as ${\mathrm{CaCO}}_3$, is a common compound found in rocks such as limestone, and it behaves differently from the chlorates and perchlorates discussed previously. When decomposed by heating, Calcium Carbonate doesn't produce oxygen, but rather Carbon Dioxide and Calcium Oxide.
Its decomposition can be expressed by the chemical equation:

$${\mathrm{CaCO}}_3(s)\to \mathrm{CaO}(s)+{\mathrm{CO}}_2(g)$$

This reaction reveals that Calcium Carbonate yields calcium in the form of Calcium Oxide and carbon in the form of Carbon Dioxide gas.

Key details about Calcium Carbonate decomposition:

• It's used in various industrial applications like cement production, where the calcium oxide formed is an essential component.
• The reaction is endothermic, meaning it requires heat to proceed.
• The release of ${\mathrm{CO}}_2$ has implications for environmental considerations, as it contributes to greenhouse gas emissions.

Overall, Calcium Carbonate's role is enormous in geological and industrial contexts but is non-contributing to oxygen release in heating processes.

Lead Nitrate

Lead Nitrate, ${\mathrm{Pb}(\mathrm{NO}}_3{)}_2$, is a compound that exhibits an interesting decomposition behavior. When subjected to heat, it breaks down into several products, one of which is oxygen gas.
The breakdown of Lead Nitrate can be noted by the reaction:

$${2\mathrm{Pb}(\mathrm{NO}}_3{)}_2(s)\to 2\mathrm{PbO}(s)+4{\mathrm{NO}}_2(g)+{\mathrm{O}}_2(g)$$

This equation demonstrates that Lead Nitrate decomposes to form Lead Oxide ($\mathrm{PbO}$), Nitrogen Dioxide (${\mathrm{NO}}_2$), and Oxygen gas.

Important considerations for this reaction include:

• The process is complex, yielding multiple products, each with distinct chemical properties.
• Lead Nitrate is often used in laboratories to produce oxidizing reactions because of its decomposition releasing oxygen.
• Care needs to be taken because the reaction also produces Nitrogen Dioxide, a harmful gas.

Understanding the decomposition of Lead Nitrate is crucial in both chemical synthesis and safety practices due to its toxic products and usefulness in oxygen-releasing applications.