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)Ensure To Include The Proper Sign. Do Not Include Units.$\ldots C_2 H_4(g) + \ldots

Introduction

In chemistry, the enthalpy of reaction is a crucial concept that helps us understand the energy changes that occur during a chemical reaction. The enthalpy of reaction, denoted by $\Delta H$, is the change in enthalpy that occurs when a reaction is carried out at constant pressure. In this article, we will learn how to calculate the $\Delta H$ of reaction for a given chemical reaction using the heats of formation table in a data booklet.

Balancing the Equation

Before we can calculate the $\Delta H$ of reaction, we need to balance the chemical 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 take the given reaction as an example:

$\ldots C_2 H_4(g) + \ldots$

To balance this equation, we need to determine the products and reactants involved in the reaction. For the sake of this example, let's assume the reaction is:

$C_2 H_4(g) + O_2(g) \rightarrow CO_2(g) + H_2O(l)$

Now that we have a balanced equation, 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 formula:

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

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

Heats of Formation Table

The heats of formation table in a data booklet provides the values of $\Delta H_f$ for various substances. The table typically lists the substances in alphabetical order, along with their corresponding $\Delta H_f$ values. For example:

Substance	$\Delta H_f$
$C_2 H_4(g)$	-52.26
$CO_2(g)$	-393.51
$H_2O(l)$	-285.83
$O_2(g)$	0

Calculating the $\Delta H$ of Reaction for the Given Reaction

Now that we have the heats of formation table, we can calculate the $\Delta H$ of reaction for the given reaction. Using the formula above, we get:

$\Delta H = \Delta H_f(\text{CO}_2) + \Delta H_f(\text{H}_2\text{O}) - \Delta H_f(\text{C}_2\text{H}_4) - \Delta H_f(\text{O}_2)$

Substituting the values from the heats of formation table, we get:

$\Delta H = -393.51 + (-285.83) - (-52.26) - 0$

Simplifying the expression, we get:

$\Delta H = -627.08$

Conclusion

In this article, we learned how to calculate the $\Delta H$ of reaction for a given chemical reaction using the heats of formation table in a data booklet. We balanced the chemical equation, determined the products and reactants involved in the reaction, and calculated the $\Delta H$ of reaction using the formula above. The result is a negative value, indicating that the reaction is exothermic.

Tips and Tricks

• Always balance the chemical equation before calculating the $\Delta H$ of reaction.
• Use the heats of formation table in a data booklet to determine the $\Delta H_f$ values of the substances involved in the reaction.
• Make sure to include the proper sign when reporting the $\Delta H$ of reaction.

Common Mistakes to Avoid

• Failing to balance the chemical equation before calculating the $\Delta H$ of reaction.
• Using incorrect values from the heats of formation table.
• Failing to include the proper sign when reporting the $\Delta H$ of reaction.

Real-World Applications

The $\Delta H$ of reaction is an important concept in chemistry that has numerous real-world applications. Some examples include:

• Thermodynamics: The $\Delta H$ of reaction is used to determine the energy changes that occur during a chemical reaction.
• Chemical Engineering: The $\Delta H$ of reaction is used to design and optimize chemical processes.
• Environmental Science: The $\Delta H$ of reaction is used to study the energy changes that occur during environmental processes, such as the combustion of fossil fuels.

Conclusion

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Q: What is the enthalpy of reaction?

A: The enthalpy of reaction, denoted by $\Delta H$, is the change in enthalpy that occurs when a reaction is carried out at constant pressure. It is a measure of the energy change that occurs during a chemical reaction.

Q: Why is it important to balance the chemical equation before calculating the $\Delta H$ of reaction?

A: Balancing the chemical equation is crucial before calculating the $\Delta H$ of reaction because it ensures that the number of atoms of each element is the same on both the reactant and product sides. This is necessary to accurately calculate the $\Delta H$ of reaction.

Q: What is the heats of formation table, and how is it used to calculate the $\Delta H$ of reaction?

A: The heats of formation table is a table that lists the substances in alphabetical order, along with their corresponding $\Delta H_f$ values. The $\Delta H_f$ value is the change in enthalpy that occurs when one mole of a substance is formed from its constituent elements in their standard states. The heats of formation table is used to calculate the $\Delta H$ of reaction by summing the $\Delta H_f$ values of the products and subtracting the sum of the $\Delta H_f$ values of the reactants.

Q: What is the formula for calculating the $\Delta H$ of reaction?

A: The formula for calculating the $\Delta H$ of reaction is:

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

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

A: $\Delta H$ is the change in enthalpy, while $\Delta E$ is the change in internal energy. The two are related by the equation:

$\Delta H = \Delta E + \Delta nRT$

where $\Delta n$ is the change in the number of moles of gas, $R$ is the gas constant, and $T$ is the temperature in Kelvin.

Q: Can the $\Delta H$ of reaction be negative or positive?

A: Yes, the $\Delta H$ of reaction can be either negative or positive. A negative $\Delta H$ indicates that the reaction is exothermic, meaning that it releases energy. A positive $\Delta H$ indicates that the reaction is endothermic, meaning that it absorbs energy.

Q: What are some common mistakes to avoid when calculating the $\Delta H$ of reaction?

A: Some common mistakes to avoid when calculating the $\Delta H$ of reaction include:

• Failing to balance the chemical equation before calculating the $\Delta H$ of reaction.
• Using incorrect values from the heats of formation table.
• Failing to include the proper sign when reporting the $\Delta H$ of reaction.

Q: What are some real-world applications of the $\Delta H$ of reaction?

A: Some real-world applications of the $\Delta H$ of reaction include:

• Thermodynamics: The $\Delta H$ of reaction is used to determine the energy changes that occur during a chemical reaction.
• Chemical Engineering: The $\Delta H$ of reaction is used to design and optimize chemical processes.
• Environmental Science: The $\Delta H$ of reaction is used to study the energy changes that occur during environmental processes, such as the combustion of fossil fuels.

Q: How can I calculate the $\Delta H$ of reaction for a given chemical reaction?

A: To calculate the $\Delta H$ of reaction for a given chemical reaction, follow these steps:

1. Balance the chemical equation.
2. Determine the products and reactants involved in the reaction.
3. Use the heats of formation table to determine the $\Delta H_f$ values of the products and reactants.
4. Calculate the $\Delta H$ of reaction using the formula:

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

5. Report the $\Delta H$ of reaction with the proper sign.