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.
![**Text for an Educational Website:**
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**Understanding the Lattice Energy of MX₃**
Consider an ionic compound, MX₃, composed of a generic metal M and a generic gaseous halogen X.
- **The enthalpy of formation of MX₃** is \( \Delta H_f^\circ = -775 \, \text{kJ/mol} \).
- **The enthalpy of sublimation of M** is \( \Delta H_{sub} = 131 \, \text{kJ/mol} \).
- **Ionization Energies of M:**
- First ionization energy (\( \text{IE}_1 \)): \( 649 \, \text{kJ/mol} \)
- Second ionization energy (\( \text{IE}_2 \)): \( 1613 \, \text{kJ/mol} \)
- Third ionization energy (\( \text{IE}_3 \)): \( 2711 \, \text{kJ/mol} \)
- **The electron affinity of X** is \( \Delta H_{EA} = -343 \, \text{kJ/mol} \). (Refer to the hint provided in the original context)
- **The bond energy of X₂** is \( \text{BE} = 207 \, \text{kJ/mol} \).
**Task:**
Determine the lattice energy of MX₃.
\( \Delta H_{lattice} = \) [Input box for answer] kJ/mol
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This page helps you calculate the lattice energy of an ionic compound by using given thermodynamic data and understanding the processes involved in the formation of the compound.](/v2/_next/image?url=https%3A%2F%2Fcontent.bartleby.com%2Fqna-images%2Fquestion%2F1cab08ae-8e5c-4fa2-a89b-725536e38ab3%2F1a0b651a-b4f3-4a35-a847-8741f6a0c760%2Foywkwns_processed.png&w=3840&q=75)
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