For The Process ${ 2 \text{SO}_2(g) + \text{O}_2(g) \rightarrow 2 \text{SO}_3(g)\$} , { \Delta S = -187.9 , \text{J/K}$}$ And { \Delta H = -198.4 , \text{kJ}$}$ At 297.0 K Are Known.What Is The Entropy Of This Reaction?

Introduction

Entropy is a fundamental concept in chemistry that measures the disorder or randomness of a system. It is an essential thermodynamic property that helps us understand the spontaneity of a reaction. In this article, we will explore the concept of entropy and how it relates to a specific reaction: the process of sulfur trioxide formation from sulfur dioxide and oxygen. We will use the given values of entropy change (${\Delta S}$) and enthalpy change (${\Delta H}$) to calculate the entropy of this reaction.

What is Entropy?

Entropy is a measure of the disorder or randomness of a system. It is typically denoted by the symbol ${S}$ and is measured in units of joules per kelvin (J/K). The entropy of a system can be thought of as a measure of the number of possible microstates that the system can occupy. In other words, it is a measure of the amount of thermal energy available to do work in a system.

The Reaction: Sulfur Trioxide Formation

The reaction we are interested in is:

${2 \text{SO}_2(g) + \text{O}_2(g) \rightarrow 2 \text{SO}_3(g)}$

This reaction involves the formation of sulfur trioxide (SO3) from sulfur dioxide (SO2) and oxygen (O2). The given values of entropy change (${\Delta S}$) and enthalpy change (${\Delta H}$) are:

${\Delta S = -187.9 \, \text{J/K}}$ ${\Delta H = -198.4 \, \text{kJ}}$

Calculating the Entropy of the Reaction

To calculate the entropy of the reaction, we need to use the equation:

${\Delta S = \frac{\Delta H}{T}}$

where ${\Delta H}$ is the enthalpy change and ${T}$ is the temperature in kelvin.

First, we need to convert the enthalpy change from kilojoules to joules:

${\Delta H = -198.4 \, \text{kJ} = -198,400 \, \text{J}}$

Next, we can plug in the values of ${\Delta H}$ and ${T}$ into the equation:

${\Delta S = \frac{-198,400 \, \text{J}}{297.0 \, \text{K}}}$

Simplifying the equation, we get:

${\Delta S = -669.5 \, \text{J/K}}$

However, we are given that ${\Delta S = -187.9 \, \text{J/K}}$. This suggests that the reaction is not spontaneous, as the entropy change is negative.

Understanding the Sign of the Entropy Change

The sign of the entropy change is a crucial aspect of understanding the spontaneity of a reaction. A negative entropy change indicates that the reaction is not spontaneous, as the disorder or randomness of the system decreases. In contrast, a positive entropy change indicates that the reaction is spontaneous, as the disorder or randomness of the system increases.

Conclusion

In conclusion, the entropy of the reaction is given by the equation:

${\Delta S = \frac{\Delta H}{T}}$

Using the given values of ${\Delta H}$ and ${T}$, we can calculate the entropy change of the reaction. However, we must be careful to consider the sign of the entropy change, as it can indicate whether the reaction is spontaneous or not.

References

• Atkins, P. W., & de Paula, J. (2010). Physical chemistry. Oxford University Press.
• Chang, R. (2010). Physical chemistry for the life sciences. W.H. Freeman and Company.

Further Reading

• Entropy and the second law of thermodynamics
• Spontaneity of a reaction
• Thermodynamic properties of a system
  Entropy of a Reaction: Q&A =============================

Introduction

In our previous article, we explored the concept of entropy and its relation to a specific reaction: the process of sulfur trioxide formation from sulfur dioxide and oxygen. We calculated the entropy change of the reaction using the given values of entropy change (${\Delta S}$) and enthalpy change (${\Delta H}$). In this article, we will answer some frequently asked questions related to entropy and its application in chemistry.

Q: What is the difference between entropy and enthalpy?

A: Entropy (${S}$) and enthalpy (${H}$) are two fundamental thermodynamic properties that describe the energy and disorder of a system. Entropy measures the disorder or randomness of a system, while enthalpy measures the total energy of a system, including both internal energy and the energy associated with the pressure and volume of a system.

Q: How is entropy related to the second law of thermodynamics?

A: The second law of thermodynamics states that the total entropy of an isolated system will always increase over time. This means that as energy is transferred or transformed from one form to another, some of the energy will become unavailable to do work because it becomes random and dispersed. Entropy is a measure of this disorder or randomness.

Q: What is the significance of a negative entropy change?

A: A negative entropy change indicates that the disorder or randomness of a system decreases. This can occur when a system becomes more organized or structured, such as when a gas condenses into a liquid. In the context of a reaction, a negative entropy change can indicate that the reaction is not spontaneous.

Q: Can entropy change be used to predict the spontaneity of a reaction?

A: Yes, entropy change can be used to predict the spontaneity of a reaction. If the entropy change is positive, the reaction is likely to be spontaneous. If the entropy change is negative, the reaction is likely to be non-spontaneous.

Q: How is entropy change related to the Gibbs free energy change?

A: The Gibbs free energy change (${\Delta G}$) is a measure of the energy available to do work in a system. It is related to the entropy change (${\Delta S}$) and the enthalpy change (${\Delta H}$) by the equation:

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

If the Gibbs free energy change is negative, the reaction is spontaneous.

Q: Can entropy change be used to predict the direction of a reaction?

A: Yes, entropy change can be used to predict the direction of a reaction. If the entropy change is positive, the reaction will tend to proceed in the direction that increases the disorder or randomness of the system.

Q: What are some common applications of entropy in chemistry?

A: Entropy has many applications in chemistry, including:

• Predicting the spontaneity of a reaction
• Determining the direction of a reaction
• Understanding the thermodynamics of a system
• Designing new materials and processes

Conclusion

In conclusion, entropy is a fundamental concept in chemistry that measures the disorder or randomness of a system. It is related to the second law of thermodynamics and can be used to predict the spontaneity and direction of a reaction. By understanding entropy, chemists can design new materials and processes that are more efficient and effective.

References

• Atkins, P. W., & de Paula, J. (2010). Physical chemistry. Oxford University Press.
• Chang, R. (2010). Physical chemistry for the life sciences. W.H. Freeman and Company.

Further Reading

• Entropy and the second law of thermodynamics
• Spontaneity of a reaction
• Thermodynamic properties of a system
• Gibbs free energy and its applications in chemistry