Enthalpy of Formation of Products

Oct 13, 2025 by miodeya.com 100 views

Introduction

Iron(II) chloride is a chemical compound that is formed through a reaction between iron and copper(II) chloride. This reaction is a classic example of a redox reaction, where one element loses electrons to form a cation, while another element gains electrons to form an anion. In this article, we will delve into the thermodynamics of this reaction, exploring the enthalpy of formation of the reactants and products, and how it relates to the spontaneity of the reaction.

The Reaction

The reaction between iron and copper(II) chloride is as follows:

${ Fe + CuCl_2 \rightarrow FeCl_2 + Cu }$

In this reaction, iron (Fe) reacts with copper(II) chloride (CuCl2) to form iron(II) chloride (FeCl2) and copper (Cu). The reaction is a redox reaction, where iron loses electrons to form Fe2+ ions, while copper gains electrons to form Cu+ ions.

Enthalpy of Formation

The enthalpy of formation (ΔHf) is a measure of the energy change that occurs when a compound is formed from its constituent elements in their standard states. In this case, the reactants have a negative enthalpy of formation, indicating that energy is released when they are formed:

${ \Delta H_f = -256 \, \text{kJ mol}^{-1} }$

This means that the formation of 1 mole of Fe and 1 mole of CuCl2 releases 256 kJ of energy.

Enthalpy of Formation of Products

The products of the reaction, FeCl2 and Cu, also have a negative enthalpy of formation:

${ \Delta H_f = -326 \, \text{kJ mol}^{-1} }$

This means that the formation of 1 mole of FeCl2 and 1 mole of Cu releases 326 kJ of energy.

Enthalpy Change of the Reaction

The enthalpy change of the reaction (ΔHrxn) is the difference between the enthalpy of formation of the products and the enthalpy of formation of the reactants:

${ \Delta H_{rxn} = \Delta H_f(\text{products}) - \Delta H_f(\text{reactants}) }$

Substituting the values, we get:

${ \Delta H_{rxn} = -326 \, \text{kJ mol}^{-1} - (-256 \, \text{kJ mol}^{-1}) }$

${ \Delta H_{rxn} = -70 \, \text{kJ mol}^{-1} }$

This means that the reaction is exothermic, releasing 70 kJ of energy per mole of reaction.

Spontaneity of the Reaction

The spontaneity of a reaction is determined by the sign of the enthalpy change. If the enthalpy change is negative, the reaction is exothermic and spontaneous. In this case, the enthalpy change is negative, indicating that the reaction is exothermic and spontaneous.

Conclusion

In conclusion, the reaction between iron and copper(II) chloride is a spontaneous reaction, releasing 70 kJ of energy per mole of reaction. The enthalpy of formation of the reactants and products is negative, indicating that energy is released when they are formed. The enthalpy change of the reaction is also negative, indicating that the reaction is exothermic and spontaneous.

References

[1] CRC Handbook of Chemistry and Physics, 97th ed. (2016)
[2] Kittel, C., Introduction to Solid State Physics, 8th ed. (2005)

Q: What is the iron(II) chloride formation reaction?

A: The iron(II) chloride formation reaction is a chemical reaction between iron and copper(II) chloride, resulting in the formation of iron(II) chloride and copper.

Q: What is the balanced chemical equation for the reaction?

A: The balanced chemical equation for the reaction is:

${ Fe + CuCl_2 \rightarrow FeCl_2 + Cu }$

Q: What is the enthalpy of formation of the reactants?

A: The enthalpy of formation of the reactants is -256 kJ/mol.

Q: What is the enthalpy of formation of the products?

A: The enthalpy of formation of the products is -326 kJ/mol.

Q: What is the enthalpy change of the reaction?

A: The enthalpy change of the reaction is -70 kJ/mol.

Q: Is the reaction exothermic or endothermic?

A: The reaction is exothermic, releasing 70 kJ of energy per mole of reaction.

Q: Is the reaction spontaneous or non-spontaneous?

A: The reaction is spontaneous, as indicated by the negative enthalpy change.

Q: What are the products of the reaction?

A: The products of the reaction are iron(II) chloride (FeCl2) and copper (Cu).

Q: What are the reactants of the reaction?

A: The reactants of the reaction are iron (Fe) and copper(II) chloride (CuCl2).

Q: What is the significance of the iron(II) chloride formation reaction?

A: The iron(II) chloride formation reaction is an important example of a redox reaction, where one element loses electrons to form a cation, while another element gains electrons to form an anion. This reaction is also an example of an exothermic reaction, releasing energy in the form of heat.

Q: How is the iron(II) chloride formation reaction used in industry?

A: The iron(II) chloride formation reaction is used in various industrial applications, including the production of iron(II) chloride, which is used as a catalyst in the production of polyethylene and polypropylene.

Q: What are some common applications of iron(II) chloride?

A: Iron(II) chloride is used in various applications, including:

Catalyst: Iron(II) chloride is used as a catalyst in the production of polyethylene and polypropylene.
Pigment: Iron(II) chloride is used as a pigment in the production of paints and coatings.
Medicine: Iron(II) chloride is used in medicine as a treatment for iron deficiency anemia.

Q: What are some common hazards associated with iron(II) chloride?

A: Iron(II) chloride is a hazardous substance that can cause:

Skin irritation: Iron(II) chloride can cause skin irritation and burns.
Eye irritation: Iron(II) chloride can cause eye irritation and damage.
Respiratory problems: Iron(II) chloride can cause respiratory problems, including coughing and shortness of breath.

Q: How should iron(II) chloride be handled and stored?

A: Iron(II) chloride should be handled and stored with caution, as it is a hazardous substance. It should be stored in a well-ventilated area, away from heat and flame. It should also be handled with gloves and eye protection to prevent skin and eye irritation.