Based On The Information In The Table Below, Which Of The Following Expressions Gives The Approximate \[$\Delta H^*\$\] For The Reaction Represented By The Following Balanced Chemical Equation?$\[Fe_2 O_3(s)+3 CO(g) \rightarrow 2 Fe(s)+3

Understanding Enthalpy Change

Enthalpy change, denoted by the symbol $\Delta H$, is a measure of the energy change that occurs during a chemical reaction. It is an important concept in chemistry, as it helps us understand the thermodynamics of a reaction. In this article, we will explore how to calculate the approximate enthalpy change for a given chemical reaction.

The Balanced Chemical Equation

The balanced chemical equation for the reaction is:

${Fe_2 O_3(s)+3 CO(g) \rightarrow 2 Fe(s)+3 CO_2(g)}$

The Table of Enthalpy Values

Calculating the Enthalpy Change

To calculate the approximate enthalpy change for the reaction, we need to consider the enthalpy values of the reactants and products. The enthalpy change is calculated as the sum of the enthalpy values of the products minus the sum of the enthalpy values of the reactants.

Step 1: Calculate the Enthalpy of the Reactants

The reactants in the equation are $Fe_2 O_3(s)$ and $CO(g)$. The enthalpy values of these substances are -1655 kJ/mol and -110.5 kJ/mol, respectively.

Step 2: Calculate the Enthalpy of the Products

The products in the equation are $Fe(s)$ and $CO_2(g)$. The enthalpy values of these substances are 0 kJ/mol and -393.5 kJ/mol, respectively.

Step 3: Calculate the Enthalpy Change

The enthalpy change is calculated as the sum of the enthalpy values of the products minus the sum of the enthalpy values of the reactants.

$\Delta H^* = (2 \times 0) + (3 \times -393.5) - (-1655 + 3 \times -110.5)$

$\Delta H^* = 0 - 1180.5 + 1655 - 331.5$

$\Delta H^* = 142.0$

Conclusion

In conclusion, the approximate enthalpy change for the reaction represented by the balanced chemical equation is 142.0 kJ/mol.

References

• Petrucci, R. H., Harwood, W. S., & Herring, F. G. (2016). General chemistry: Principles and modern applications. Pearson Education.
• Atkins, P. W., & De Paula, J. (2010). Physical chemistry. Oxford University Press.

Note

Q: What is enthalpy change?

A: Enthalpy change, denoted by the symbol $\Delta H$, is a measure of the energy change that occurs during a chemical reaction. It is an important concept in chemistry, as it helps us understand the thermodynamics of a reaction.

Q: How is enthalpy change calculated?

A: Enthalpy change is calculated as the sum of the enthalpy values of the products minus the sum of the enthalpy values of the reactants. The formula for calculating enthalpy change is:

$\Delta H^* = \sum n_i \Delta H_i^* (products) - \sum n_i \Delta H_i^* (reactants)$

where $n_i$ is the number of moles of each substance and $\Delta H_i^*$ is the enthalpy change of each substance.

Q: What are the units of enthalpy change?

A: The units of enthalpy change are typically measured in joules per mole (J/mol) or kilojoules per mole (kJ/mol).

Q: What is the difference between enthalpy change and internal energy change?

A: Enthalpy change ($\Delta H$) and internal energy change ($\Delta U$) are related but distinct concepts. Enthalpy change is a measure of the energy change that occurs during a chemical reaction, while internal energy change is a measure of the energy change that occurs within a system.

Q: How is enthalpy change related to the spontaneity of a reaction?

A: Enthalpy change is related to the spontaneity of a reaction through the equation:

$\Delta G = \Delta H - T \Delta S$

where $\Delta G$ is the Gibbs free energy change, $\Delta H$ is the enthalpy change, $T$ is the temperature in Kelvin, and $\Delta S$ is the entropy change.

Q: Can enthalpy change be negative or positive?

A: Yes, enthalpy change can be either negative or positive. A negative enthalpy change indicates that the reaction is exothermic, meaning that energy is released during the reaction. A positive enthalpy change indicates that the reaction is endothermic, meaning that energy is absorbed during the reaction.

Q: How is enthalpy change used in real-world applications?

A: Enthalpy change is used in a variety of real-world applications, including:

• Calculating the energy required for a chemical reaction
• Determining the spontaneity of a reaction
• Designing chemical processes and equipment
• Understanding the thermodynamics of a reaction

Q: What are some common mistakes to avoid when calculating enthalpy change?

A: Some common mistakes to avoid when calculating enthalpy change include:

• Failing to account for the number of moles of each substance
• Using incorrect values for the enthalpy change of each substance
• Failing to consider the temperature and pressure of the reaction
• Not accounting for the entropy change of the reaction

Q: Where can I find more information about enthalpy change?

A: You can find more information about enthalpy change in a variety of resources, including:

• Chemistry textbooks and online resources
• Scientific articles and research papers
• Online forums and discussion groups
• Chemistry courses and workshops