Question

Boron trifluoride is used in the electronics industry to manufacture computer chips. Draw the energy profile for the following reaction: $$ 2 \mathrm{~B}(s)+3 \mathrm{~F}_{2}(g) \rightleftarrows 2 \mathrm{BF}_{3}(g)+\text { heat } $$

Short answer

The reaction is exothermic with reactants at a higher energy than products.

Step-by-step solution

Identify Reaction Type

The given reaction is the formation of boron trifluoride from elemental boron and fluorine. The reaction releases heat, indicating it is an exothermic reaction.

Understand Exothermic Reaction Profile

In an exothermic reaction, the energy of the reactants is higher than the energy of the products. This means that energy is released as the reaction proceeds.

Draw Energy Profile Diagram

Start the diagram at a certain energy level for the reactants (2 B(s) + 3 F2(g)). Draw a downward curve showing a decrease in energy as the reaction proceeds, ending at a lower energy level for the products (2 BF3(g)). Label the y-axis as 'Energy' and the x-axis as 'Reaction Progress'. Indicate the release of energy (heat) during the reaction in the diagram.

Annotate Key Points on Diagram

Mark the reactants and products correctly on your energy diagram. Identify the peak of the curve as the transition state, where the reactants are in the process of transforming into the products. Label the energy difference between reactants and products as the amount of energy released (heat).

Key concepts

Exothermic Reactions

Exothermic reactions are fascinating chemical processes where heat is released into the surrounding environment. Picture this: you start with substances called reactants. These reactants have a certain amount of stored energy. During the reaction, some of this energy is released as heat, resulting in products that have lower energy levels than the initial reactants.

Consider the reaction between boron and fluorine to form boron trifluoride. This particular reaction is exothermic, as it releases heat.

• The initial substances (boron and fluorine) have high energy.
• As the reaction progresses, energy is released, primarily as heat.
• The resulting product, boron trifluoride, has less energy compared to the starting materials.

Understanding this concept helps in knowing the nature of chemical reactions and how they affect their surroundings.

Energy Profile Diagrams

Energy profile diagrams are useful tools for visualizing the energy changes during a chemical reaction. They provide a graphical representation of the energy content of reactants and products over the course of a reaction.

For an exothermic reaction like the formation of boron trifluoride:

• The diagram starts at a high energy level, representing the energy of the reactants.
• As the reaction proceeds, the energy drops, illustrated by a downward curve.
• This curve eventually levels out at a lower energy level for the products.
• An exit of heat is marked along this decline, emphasizing energy release.

The x-axis of the diagram tracks the progress of the reaction, while the y-axis indicates the energy levels. Such diagrams are crucial for comprehending how energy varies and is conserved during chemical processes.

Boron Compounds

Boron compounds, like boron trifluoride, have unique properties that make them vital in various industrial applications. Boron trifluoride is a compound formed from the reaction between elemental boron and fluorine.

This compound is noteworthy for several reasons:

• It acts as a Lewis acid, meaning it can accept electron pairs.
• In the electronics industry, it is used in manufacturing computer chips, showcasing its importance in tech applications.
• Boron trifluoride is a gas at room temperature, adding to its versatility and usefulness.

Understanding boron trifluoride's reactivity and applications gives insights into the broader role of boron compounds in the chemical and industrial spheres.

Transition States

In a chemical reaction, the transition state represents a crucial, high-energy point where reactants transform into products. It's depicted as the peak on an energy profile diagram.

Imagine a hilltop: the transition state is the very top of this hill. Once you reach the peak, you proceed downwards, much like how the energy decreases after reaching this state in a reaction.

• The transition state is transient and difficult to observe directly.
• It signifies the moment where chemical bonds are in the process of breaking and forming.
• This state requires activation energy—extra energy to start the reaction.

Recognizing transition states helps in understanding how reactions proceed and the energy required to overcome reaction barriers.