Calculate The $\Delta H$ Of Reaction For The Following Reaction Using The Heats Of Formation Table In Your Data Booklet. (Tip: Balance The Equation First. Include The Proper Sign For $\Delta H$, But Do Not Include Units.)$\[

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Introduction

In chemistry, the calculation of the enthalpy change ($\Delta H$) of a reaction is a crucial aspect of understanding the thermodynamics of a process. The enthalpy change is a measure of the energy change that occurs during a chemical reaction, and it can be calculated using the heats of formation of the reactants and products. In this article, we will guide you through the process of calculating the $\Delta H$ of reaction using the heats of formation table in your data booklet.

Balancing the Equation

Before we can calculate the $\Delta H$ of reaction, we need to balance the equation. A balanced equation is one in which the number of atoms of each element is the same on both the reactant and product sides. Let's consider the following reaction:

2NO(g) + O2(g) → 2NO2(g)

To balance this equation, we need to make sure that the number of nitrogen (N) and oxygen (O) atoms is the same on both sides. We can do this by adding coefficients to the reactants and products.

2NO(g) + 1/2O2(g) → 2NO2(g)

Now that the equation is balanced, we can proceed to calculate the $\Delta H$ of reaction.

Calculating the $\Delta H$ of Reaction

The $\Delta H$ of reaction can be calculated using the following equation:

$\Delta H = \sum \Delta H_f(\text{products}) - \sum \Delta H_f(\text{reactants})$

where $\Delta H_f$ is the heat of formation of a substance. The heat of formation is the energy change that occurs when one mole of a substance is formed from its constituent elements in their standard states.

Let's consider the heats of formation of the reactants and products in the balanced equation:

• NO(g): $\Delta H_f = -90.25$ kJ/mol
• O2(g): $\Delta H_f = 0$ kJ/mol (since O2 is an element in its standard state)
• NO2(g): $\Delta H_f = -51.30$ kJ/mol

Now we can calculate the $\Delta H$ of reaction:

$\Delta H = 2 \times (-51.30) - (2 \times (-90.25) + 1/2 \times 0)$

$\Delta H = -102.60 - (-180.50)$

$\Delta H = -102.60 + 180.50$

$\Delta H = 77.90$

Therefore, the $\Delta H$ of reaction for the given reaction is 77.90 kJ.

Tips and Tricks

• Make sure to balance the equation before calculating the $\Delta H$ of reaction.
• Use the correct heats of formation values from the data booklet.
• Double-check your calculations to ensure that you get the correct answer.

Conclusion

Calculating the $\Delta H$ of reaction is an important aspect of understanding the thermodynamics of a process. By following the steps outlined in this article, you can calculate the $\Delta H$ of reaction using the heats of formation table in your data booklet. Remember to balance the equation, use the correct heats of formation values, and double-check your calculations to ensure that you get the correct answer.

Common Mistakes to Avoid

• Failing to balance the equation before calculating the $\Delta H$ of reaction.
• Using incorrect heats of formation values from the data booklet.
• Not double-checking calculations to ensure that the correct answer is obtained.

Real-World Applications

Calculating the $\Delta H$ of reaction has numerous real-world applications in fields such as:

• Chemical engineering: Understanding the thermodynamics of a process is crucial in designing and optimizing chemical reactors.
• Materials science: Calculating the $\Delta H$ of reaction can help predict the properties of materials, such as their melting points and boiling points.
• Environmental science: Understanding the thermodynamics of a process can help predict the environmental impact of a reaction, such as the release of greenhouse gases.

Further Reading

For further reading on calculating the $\Delta H$ of reaction, we recommend the following resources:

• "Thermodynamics: An Introduction to the Physical Theories of Equilibrium Thermostatics and Irreversible Thermodynamics" by Donald T. Cromer
• "Chemical Thermodynamics: Principles and Applications" by Richard J. Silbey and Robert A. Alberty
• "Thermodynamics and Kinetics: An Introduction to the Physical Theories of Equilibrium and Irreversible Processes" by Donald T. Cromer

Glossary

• Enthalpy change: The energy change that occurs during a chemical reaction.
• Heat of formation: The energy change that occurs when one mole of a substance is formed from its constituent elements in their standard states.
• Standard state: The state of an element or compound at a temperature of 25°C and a pressure of 1 atm.
• Thermodynamics: The study of the relationships between heat, work, and energy in a system.
  Calculating the $\Delta H$ of Reaction: A Q&A Guide =====================================================

Introduction

In our previous article, we discussed the steps involved in calculating the enthalpy change ($\Delta H$) of a reaction using the heats of formation table in your data booklet. However, we understand that there may be some questions and doubts that you may have. In this article, we will address some of the most frequently asked questions related to calculating the $\Delta H$ of reaction.

Q&A

Q: What is the difference between $\Delta H$ and $\Delta E$?

A: $\Delta H$ (enthalpy change) and $\Delta E$ (internal energy change) are two related but distinct thermodynamic properties. $\Delta H$ is the energy change that occurs during a chemical reaction, while $\Delta E$ is the energy change that occurs within the system. In general, $\Delta H$ is a more useful quantity to calculate, as it takes into account the energy changes that occur during a reaction.

Q: How do I determine the heat of formation of a substance?

A: The heat of formation of a substance can be found in the data booklet or by consulting a reliable source, such as a scientific journal or a textbook. The heat of formation is typically listed in units of kJ/mol.

Q: What is the significance of the sign of $\Delta H$?

A: The sign of $\Delta H$ indicates whether the reaction is endothermic or exothermic. A positive $\Delta H$ indicates that the reaction is endothermic, meaning that it absorbs energy from the surroundings. A negative $\Delta H$ indicates that the reaction is exothermic, meaning that it releases energy to the surroundings.

Q: Can I calculate the $\Delta H$ of reaction for a reaction that involves multiple steps?

A: Yes, you can calculate the $\Delta H$ of reaction for a reaction that involves multiple steps. To do this, you need to calculate the $\Delta H$ of each individual step and then sum them up to obtain the total $\Delta H$ of reaction.

Q: How do I handle reactions that involve gases?

A: When dealing with reactions that involve gases, you need to take into account the change in the number of moles of gas. This can be done by using the ideal gas law or by consulting a reliable source, such as a scientific journal or a textbook.

Q: Can I calculate the $\Delta H$ of reaction for a reaction that involves a catalyst?

A: Yes, you can calculate the $\Delta H$ of reaction for a reaction that involves a catalyst. However, you need to take into account the fact that the catalyst does not change the energy of the reaction, but rather speeds up the reaction.

Q: How do I handle reactions that involve solids?

A: When dealing with reactions that involve solids, you need to take into account the change in the number of moles of solid. This can be done by using the ideal gas law or by consulting a reliable source, such as a scientific journal or a textbook.

Q: Can I calculate the $\Delta H$ of reaction for a reaction that involves a phase change?

A: Yes, you can calculate the $\Delta H$ of reaction for a reaction that involves a phase change. However, you need to take into account the fact that the phase change involves a change in the energy of the system.

Conclusion

Calculating the $\Delta H$ of reaction is an important aspect of understanding the thermodynamics of a process. By following the steps outlined in this article and addressing some of the most frequently asked questions, you can gain a better understanding of how to calculate the $\Delta H$ of reaction.

Common Mistakes to Avoid

• Failing to balance the equation before calculating the $\Delta H$ of reaction.
• Using incorrect heats of formation values from the data booklet.
• Not double-checking calculations to ensure that the correct answer is obtained.
• Failing to take into account the change in the number of moles of gas or solid.
• Not considering the effect of a catalyst on the reaction.

Real-World Applications

Calculating the $\Delta H$ of reaction has numerous real-world applications in fields such as:

• Chemical engineering: Understanding the thermodynamics of a process is crucial in designing and optimizing chemical reactors.
• Materials science: Calculating the $\Delta H$ of reaction can help predict the properties of materials, such as their melting points and boiling points.
• Environmental science: Understanding the thermodynamics of a process can help predict the environmental impact of a reaction, such as the release of greenhouse gases.

Further Reading

For further reading on calculating the $\Delta H$ of reaction, we recommend the following resources:

• "Thermodynamics: An Introduction to the Physical Theories of Equilibrium Thermostatics and Irreversible Thermodynamics" by Donald T. Cromer
• "Chemical Thermodynamics: Principles and Applications" by Richard J. Silbey and Robert A. Alberty
• "Thermodynamics and Kinetics: An Introduction to the Physical Theories of Equilibrium and Irreversible Processes" by Donald T. Cromer

Glossary

• Enthalpy change: The energy change that occurs during a chemical reaction.
• Heat of formation: The energy change that occurs when one mole of a substance is formed from its constituent elements in their standard states.
• Standard state: The state of an element or compound at a temperature of 25°C and a pressure of 1 atm.
• Thermodynamics: The study of the relationships between heat, work, and energy in a system.