Question

Write this reaction in terms of formation reactions. \(\mathrm{SiH}_{4}+4 \mathrm{~F}_{2} \rightarrow \mathrm{SiF}_{4}+4 \mathrm{HF}\)

Short answer

Write elemental formation reactions for \(\mathrm{SiH}_{4}, \mathrm{F}_{2}, \mathrm{SiF}_{4},\) and \(\mathrm{HF}.\)

Step-by-step solution

Identify the Products and Reactants

In the given reaction, the reactants are \(\mathrm{SiH}_{4}\) (silicon tetrahydride) and \(\mathrm{F}_{2}\) (fluorine gas), and the products are \(\mathrm{SiF}_{4}\) (silicon tetrafluoride) and \(\mathrm{HF}\) (hydrofluoric acid).

Formation Reaction for \(\mathrm{SiH}_{4}\)

The formation reaction for \(\mathrm{SiH}_{4}\) is: \[ \mathrm{Si(s)} + 2 \mathrm{H}_{2(g)} \rightarrow \mathrm{SiH}_{4(g)} \]This reaction shows the formation of \(\mathrm{SiH}_{4}\) from its elements in their standard states.

Formation Reaction for \(\mathrm{F}_{2}\)

The formation reaction for \(\mathrm{F}_{2}\) from fluorine atoms is: \[ 2\mathrm{F(g)} \rightarrow \mathrm{F}_{2(g)} \]Although \(\mathrm{F}_{2}\) is often found as a diatomic molecule naturally, this is considered its elemental form.

Formation Reaction for \(\mathrm{SiF}_{4}\)

The formation reaction for \(\mathrm{SiF}_{4}\) is: \[ \mathrm{Si(s)} + 2 \mathrm{F}_{2(g)} \rightarrow \mathrm{SiF}_{4(g)} \]This equation demonstrates \(\mathrm{SiF}_{4}\) formed from silicon and fluorine in their standard states.

Formation Reaction for \(\mathrm{HF}\)

The formation reaction for \(\mathrm{HF}\) is: \[ \mathrm{H}_{2(g)} + \mathrm{F}_{2(g)} \rightarrow 2 \mathrm{HF(g)} \]This equation shows \(\mathrm{HF}\) formed from hydrogen and fluorine gases in their elemental forms.

Key concepts

formation reaction

Formation reactions are a class of chemical reactions where a compound is formed from its constituent elements in their natural state. Such reactions are immensely useful in understanding thermodynamics, especially when calculating the standard enthalpy of formation. For instance, the formation reaction of silicon tetrahydride (\( \mathrm{SiH}_4 \)) from its elementary components would be written as: \[ \mathrm{Si(s)} + 2 \mathrm{H}_{2(g)} \rightarrow \mathrm{SiH}_{4(g)} \]. This reaction uses silicon in its solid state and hydrogen gas as reactants, which are then combined to form \( \mathrm{SiH}_4 \) in its gaseous form.

• Formation reactions help identify how a compound is formed from its elements.
• They are crucial for calculating the heat change in reactions.

Given their broad applications, understanding these reactions forms the backbone of thermochemistry.

reactants and products

In any chemical reaction, it's important to distinguish between the reactants and the products. Reactants are the starting substances that undergo change, while products are the new substances formed as a result of the reaction. In the reaction \( \mathrm{SiH}_4 + 4 \mathrm{F}_2 \rightarrow \mathrm{SiF}_4 + 4 \mathrm{HF} \), the reactants are \( \mathrm{SiH}_4 \) (silicon tetrahydride) and \( \mathrm{F}_2 \) (fluorine gas), while the products are \( \mathrm{SiF}_4 \) (silicon tetrafluoride) and \( \mathrm{HF} \) (hydrofluoric acid). Understanding the classification of these components is essential for writing balanced equations and for performing stoichiometric calculations in chemistry.

• Identifying reactants and products helps predict the direction of the reaction.
• It allows for a better understanding of the transformation processes taking place.

elemental states

Elemental states refer to the physical form in which an element exists naturally. This can be solid, liquid, gas, or plasma. In a formation reaction, each reactant must be in its natural or elemental state. For example, silicon (\( \mathrm{Si} \)) is usually found as a solid, while fluorine (\( \mathrm{F}_2 \)) is typically a diatomic gas. Recognizing these states is crucial for predicting reactions and writing correct formation reactions.Some elements, like noble gases, naturally exist as individual atoms (\( \mathrm{He} \), \( \mathrm{Ne} \)). Others, like oxygen and nitrogen, exist as diatomic molecules (\( \mathrm{O}_2 \), \( \mathrm{N}_2 \)). Understanding elemental states helps in:

• Determining how elements react with one another.
• Identifying the natural physical forms of elements to predict their chemical behavior.

standard states

Standard states refer to a set of conditions used to measure the properties of elements and compounds. This typically means at a pressure of 1 atmosphere and a defined temperature, often 25°C (298 K). Understanding standard states is crucial for interpreting formation reactions and thermodynamic data.Consider the formation reaction of \( \mathrm{SiF}_4 \): \[ \mathrm{Si(s)} + 2 \mathrm{F}_{2(g)} \rightarrow \mathrm{SiF}_{4(g)} \]. Here, the reaction assumes silicon and fluorine in their standard states, which are solid and gaseous, respectively. Knowing the standard states helps in:

• Providing a common reference point to compare different reactions and data.
• Understanding how deviations from these conditions might affect the reaction dynamics.

Without a benchmark like the standard state, comparing data across different experiments becomes challenging.