Titanium Reacts With Iodine Reaction, Calculations, And Applications

Titanium, a strong, lightweight, and corrosion-resistant metal, exhibits a fascinating chemical behavior, especially when reacting with halogens like iodine. The exothermic reaction between titanium and iodine produces titanium(III) iodide, releasing a significant amount of heat. This comprehensive guide delves into the intricacies of this reaction, providing a detailed explanation, calculation examples, and a thorough exploration of the underlying chemistry.

The reaction between titanium and iodine is represented by the following balanced chemical equation:

$2 Ti(s) + 3 I_2(g) \rightarrow 2 TiI_3(s), \quad \Delta H_{rxn}^{o} = -839 kJ$

This equation tells us that two moles of solid titanium react with three moles of gaseous iodine to produce two moles of solid titanium(III) iodide. The negative value of the standard enthalpy change of reaction, $\Delta H_{rxn}^{o} = -839 kJ$, indicates that the reaction is highly exothermic, meaning it releases a considerable amount of heat into the surroundings. This heat release is a crucial aspect of the reaction, influencing its rate and the overall energy balance of the system.

Understanding the Reaction Mechanism

The reaction between titanium and iodine involves the transfer of electrons from titanium to iodine. Titanium, a transition metal, has a strong tendency to lose electrons and form positive ions. Iodine, a halogen, has a high electronegativity, meaning it readily accepts electrons to form negative ions. In this reaction, each titanium atom loses three electrons to form a Ti³⁺ ion, while each iodine molecule gains two electrons (each iodine atom gains one electron) to form two I⁻ ions. These ions then combine to form the ionic compound titanium(III) iodide (TiI₃).

The reaction can be visualized as a multi-step process:

1. Adsorption: Iodine molecules initially adsorb onto the surface of the titanium metal. This adsorption process brings the reactants into close proximity, facilitating the electron transfer.
2. Electron Transfer: Titanium atoms on the surface lose electrons to the adsorbed iodine molecules. This electron transfer leads to the formation of Ti³⁺ ions and I⁻ ions.
3. Bond Formation: The Ti³⁺ and I⁻ ions combine to form the titanium(III) iodide (TiI₃) compound. This compound precipitates out as a solid.
4. Heat Release: The formation of the strong ionic bonds in TiI₃ releases a significant amount of energy in the form of heat, making the reaction exothermic.

Factors Affecting the Reaction Rate

Several factors can influence the rate of the reaction between titanium and iodine:

• Temperature: Higher temperatures generally increase the reaction rate. This is because higher temperatures provide the reactant molecules with more kinetic energy, increasing the frequency and energy of collisions, and thus the likelihood of successful reactions. In the case of this exothermic reaction, the heat released further accelerates the reaction at higher temperatures.
• Concentration/Partial Pressure: Higher concentrations of reactants (or higher partial pressures in the case of gaseous iodine) also tend to increase the reaction rate. A higher concentration means there are more reactant molecules available to collide and react, leading to a faster reaction.
• Surface Area: The surface area of the titanium metal significantly affects the reaction rate. A larger surface area provides more sites for iodine molecules to adsorb and react, leading to a faster reaction. This is why finely divided titanium powder reacts much more rapidly with iodine than a solid block of titanium.
• Presence of a Catalyst: Although not explicitly required for this reaction, certain catalysts can potentially enhance the reaction rate. Catalysts provide an alternative reaction pathway with a lower activation energy, thus speeding up the reaction without being consumed themselves.

Part A Determining the Mass of Titanium Reacted

Now, let's address the specific question posed in Part A: Determine the mass of titanium that reacts if 2.10 x 10³ kJ of heat is emitted.

To solve this problem, we will use the stoichiometric relationship between the heat released and the amount of titanium reacted, as provided by the balanced chemical equation and the enthalpy change of reaction.

Step-by-Step Solution

1. Identify the Given Information:

   • Heat emitted (q) = 2.10 x 10³ kJ
   • Enthalpy change of reaction ($\Delta H_{rxn}^{o}$) = -839 kJ (for 2 moles of Ti)

2. Establish the Stoichiometric Relationship:

The balanced equation, $2 Ti(s) + 3 I_2(g) \rightarrow 2 TiI_3(s)$, tells us that 2 moles of titanium react to release 839 kJ of heat. We can write this relationship as a ratio:

$\frac{2 \text{ moles Ti}}{839 \text{ kJ}}$

3. Calculate Moles of Titanium Reacted:

We can use the given heat emitted and the stoichiometric ratio to calculate the moles of titanium reacted:

$\text{Moles of Ti} = 2.10 \times 10^3 \text{ kJ} \times \frac{2 \text{ moles Ti}}{839 \text{ kJ}} $

$\text{Moles of Ti} = 5.01 \text{ moles Ti}$ (approximately)

4. Convert Moles of Titanium to Mass:

To find the mass of titanium, we need to use the molar mass of titanium (Ti), which is approximately 47.87 g/mol.

$\text{Mass of Ti} = 5.01 \text{ moles Ti} \times \frac{47.87 \text{ g Ti}}{1 \text{ mole Ti}}$

$\text{Mass of Ti} = 239.83 \text{ g Ti}$ (approximately)

Answer to Part A

Therefore, the mass of titanium that reacts if 2.10 x 10³ kJ of heat is emitted is approximately 239.83 grams.

Additional Aspects of the Titanium-Iodine Reaction

Applications of Titanium(III) Iodide

Titanium(III) iodide (TiI₃) is a versatile compound with several applications:

• Catalysis: TiI₃ is used as a catalyst in various organic reactions, including polymerization and oxidation reactions. Its ability to readily change oxidation states makes it an effective catalyst.
• Reducing Agent: TiI₃ is a strong reducing agent, meaning it readily donates electrons to other substances. This property makes it useful in chemical synthesis.
• Precursor for Other Titanium Compounds: TiI₃ can be used as a precursor to synthesize other titanium compounds, such as titanium dioxide (TiO₂), which is a widely used pigment and photocatalyst.

Safety Precautions

When working with titanium, iodine, and titanium(III) iodide, it is crucial to take appropriate safety precautions:

• Iodine is corrosive and toxic: Handle iodine in a well-ventilated area and avoid contact with skin and eyes. Use appropriate personal protective equipment (PPE), such as gloves and safety glasses.
• Titanium dust is flammable: Finely divided titanium powder can be flammable and may even explode if ignited. Avoid creating dust clouds and use proper grounding techniques when handling titanium powder.
• Titanium(III) iodide is air-sensitive: TiI₃ can react with air and moisture. Store TiI₃ in a dry, inert atmosphere.
• Exothermic reactions can be hazardous: The reaction between titanium and iodine releases a significant amount of heat, which can cause burns or ignite flammable materials. Perform the reaction in a controlled environment and use appropriate cooling measures if necessary.

Conclusion

The reaction between titanium and iodine is a fascinating example of an exothermic chemical reaction. Understanding the stoichiometry, reaction mechanism, and factors affecting the reaction rate is crucial for performing calculations and handling the reaction safely. Titanium(III) iodide, the product of this reaction, is a versatile compound with applications in catalysis, chemical synthesis, and as a precursor for other titanium compounds. By mastering the concepts presented in this guide, you can gain a deeper understanding of this important chemical reaction and its applications.