Calculating enthalpy: a) Given 2Fe(s) + 1.5 O₂(g) → Fe₂O3 (S) AH, = = -206 kJ mol-¹, 3 Fe(s) + 2 O₂(g) → Fe3O4 (s) determine AH, for the following reaction: AH = -136 kJ mol-¹, 4Fe₂O3(s) + Fe(s) →3Fe3O4 (S) Is this reaction exothermic or endothermic? Is this enough information to inform whether this reaction occurs or not? b) Given AH vap of water at 373 K = 40.7 kJ mol¹¹, C₂(l)=75.2 J mol-¹K-¹ and Cp (g)=33.6 J mol¹¹K¹, calculate AHvap of water at 298 K.
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.
![## Calculating Enthalpy
### a) Given Reactions:
1. \(2\text{Fe}(s) + 1.5 \text{O}_2(g) \rightarrow \text{Fe}_2\text{O}_3(s)\), \(\Delta H^\circ_r = -206 \, \text{kJ mol}^{-1}\)
2. \(3 \text{Fe}(s) + 2 \text{O}_2(g) \rightarrow \text{Fe}_3\text{O}_4(s)\), \(\Delta H^\circ_r = -136 \, \text{kJ mol}^{-1}\)
### Task:
Determine \(\Delta H^\circ_r\) for the following reaction:
\[4\text{Fe}_2\text{O}_3(s) + \text{Fe}(s) \rightarrow 3\text{Fe}_3\text{O}_4(s)\]
Is this reaction exothermic or endothermic? Is this enough information to inform whether this reaction occurs or not?
### b) Given Data:
- \(\Delta H^\circ_{\text{vap}}\) of water at 373 K = 40.7 kJ mol\(^{-1}\)
- \(\overline{C}_p(l)=75.2 \, \text{J mol}^{-1}\text{K}^{-1}\)
- \(\overline{C}_p(g)=33.6 \, \text{J mol}^{-1}\text{K}^{-1}\)
### Task:
Calculate \(\Delta H^\circ_{\text{vap}}\) of water at 298 K.](/v2/_next/image?url=https%3A%2F%2Fcontent.bartleby.com%2Fqna-images%2Fquestion%2Fdc99cc4f-9438-44d8-9b43-49724a6b39cf%2Fe94ad08f-5d09-4575-9492-73adad07fb23%2F426vpjo_processed.png&w=3840&q=75)
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