Part A Calculate the enthalpy of the reaction 2NO(g) + O2(g)→2NO2(g) given the following reactions and enthalpies of formation: 1. N2(g) + O2(g)→NO2(g), AH¡ = 33.2 kJ 2. N2(g)+ O2(g)→NO(g), AH= 90.2 kJ Express your answer with the appropriate units. • View Available Hint(s) ? Value kJ AH° =
Thermochemistry
Thermochemistry can be considered as a branch of thermodynamics that deals with the connections between warmth, work, and various types of energy, formed because of different synthetic and actual cycles. Thermochemistry describes the energy changes that occur as a result of reactions or chemical changes in a substance.
Exergonic Reaction
The term exergonic is derived from the Greek word in which ‘ergon’ means work and exergonic means ‘work outside’. Exergonic reactions releases work energy. Exergonic reactions are different from exothermic reactions, the one that releases only heat energy during the course of the reaction. So, exothermic reaction is one type of exergonic reaction. Exergonic reaction releases work energy in different forms like heat, light or sound. For example, a glow stick releases light making that an exergonic reaction and not an exothermic reaction since no heat is released. Even endothermic reactions at very high temperature are exergonic.
![### Understanding Hess's Law
Hess's law states that "the heat released or absorbed in a chemical process is the same whether the process takes place in one or in several steps." This principle is fundamental in thermochemistry and requires an understanding of the following rules:
1. **Addition of Reactions**: When two reactions are combined, their enthalpy values are also added together.
2. **Reversing Reactions**: If a reaction is reversed, the sign of its enthalpy value must be changed.
3. **Multiplying Reactions**: If the coefficients in a reaction are multiplied by a factor, the enthalpy value is also multiplied by that same factor.
### Example Problem
**Part A: Calculating the Enthalpy of Reaction**
Given the target reaction:
\[
2 \text{NO(g)} + \text{O}_2\text{(g)} \rightarrow 2 \text{NO}_2\text{(g)}
\]
And the following reactions with their enthalpies of formation:
1. \(\frac{1}{2} \text{N}_2\text{(g)} + \text{O}_2\text{(g)} \rightarrow \text{NO}_2\text{(g)}, \quad \Delta H^\circ_A = 33.2 \text{ kJ}\)
2. \(\frac{1}{2} \text{N}_2\text{(g)} + \frac{1}{2} \text{O}_2\text{(g)} \rightarrow \text{NO(g)}, \quad \Delta H^\circ_B = 90.2 \text{ kJ}\)
**Task**: Express your answer with the appropriate units using the principles of Hess's law to find the enthalpy change for the target reaction.
**Input Box**: The enthalpy change (\(\Delta H^\circ\)) response area is provided in kilojoules (kJ) to submit your calculated answer.
**Visualization**: This section helps in understanding the step-by-step application of Hess's law to deduce the desired enthalpy change. The interactive hints can guide you through the calculation process.](/v2/_next/image?url=https%3A%2F%2Fcontent.bartleby.com%2Fqna-images%2Fquestion%2F4a2bd348-d826-4056-b9ee-5fd404bc60f1%2Ff89be83c-30f2-4cad-92e0-f6422457112d%2Fydu5l6p_processed.png&w=3840&q=75)
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