2) Use the following equations to find the lattice energy of MgCl₂? (hint: first write the equation for the lattice energy of MgCl2(s)) Mg(g) → Mg2+(g) + 2 e CI(B) + eCl (g) Mgig) + 2Cl(g) → MgCl₂(s) +2188 kJ/mol -337 kJ/mol AH = -642 kJ/mol
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.
![**Title: Understanding Lewis Dot Structures and Lattice Energy Calculations**
---
**Section 1: Lewis Dot Structure for Elemental Nitrogen**
1. **Draw the Lewis dot structure for elemental nitrogen:**
- The Lewis dot structure for nitrogen is represented as:
\[
: \mathbf{N} :
\]
- This indicates that nitrogen has five valence electrons represented as dots around the atomic symbol 'N'.
**Section 2: Calculating Lattice Energy of MgCl₂**
2. **Use the following equations to find the lattice energy of MgCl₂.**
- **Hint:** First, write the equation for the lattice energy of MgCl₂(s).
- Equations provided:
\[
\text{Mg(g)} \rightarrow \text{Mg}^{2+}(\text{g}) + 2\text{e}^- \quad (+2188 \, \text{kJ/mol})
\]
\[
\text{Cl(g)} + \text{e}^- \rightarrow \text{Cl}^-(\text{g}) \quad (-337 \, \text{kJ/mol})
\]
\[
\text{Mg(g)} + 2\text{Cl(g)} \rightarrow \text{MgCl}_2(\text{s}) \quad (\Delta H_f^\circ = -642 \, \text{kJ/mol})
\]
- **Explanation:**
- The first equation represents the ionization of gaseous magnesium to form magnesium ions with two electrons released.
- The second equation involves the formation of chloride ions from gaseous chlorine atoms.
- The third equation provides the enthalpy change for the formation of solid magnesium chloride from gaseous magnesium and chlorine.
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**Note:** Calculating lattice energy involves considering the energy changes associated with forming a crystalline solid from gaseous ions, often derived from a Born-Haber cycle.](/v2/_next/image?url=https%3A%2F%2Fcontent.bartleby.com%2Fqna-images%2Fquestion%2F7e7ec386-76bc-41a0-a538-c4aa6935849e%2F335b5e3e-186b-4086-af81-763293e44016%2Fss3sgb_processed.jpeg&w=3840&q=75)
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