want: C(s) + 2 S(s) known: C(s) + O₂(g) S(s) + O2(g) CS-1 al -> CS₂(1) CO₂(g) -> SO₂(g) CO-lal 2 SO-la) ΔΗ = ??? ΔΗ = -393.5 kJ ΔΗ = -296.8 kJ - HV 110201
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.
![### Chemical Reaction Enthalpies
**Objective:**
Determine the enthalpy change (\( \Delta H \)) for the desired reaction:
\[ \text{C(s) + 2 S(s)} \rightarrow \text{CS}_2(l) \quad \Delta H = ??? \]
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**Known Reactions:**
1. **Carbon Combustion:**
\[ \text{C(s) + O}_2(g) \rightarrow \text{CO}_2(g) \]
\[ \Delta H = -393.5 \, \text{kJ} \]
2. **Sulfur Combustion:**
\[ \text{S(s) + O}_2(g) \rightarrow \text{SO}_2(g) \]
\[ \Delta H = -296.8 \, \text{kJ} \]
3. **Carbon Disulfide Combustion:**
\[ \text{CS}_2(l) + 3 \text{O}_2(g) \rightarrow \text{CO}_2(g) + 2 \text{SO}_2(g) \]
\[ \Delta H = -1103.9 \, \text{kJ} \]
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**Explanation:**
To find the enthalpy change for the reaction forming carbon disulfide (\( \text{CS}_2(l) \)), use Hess's Law by combining the known reactions.
- **Hess's Law** states that the total enthalpy change is the same regardless of the path taken, making it possible to use known reactions to calculate the unknown enthalpy change.
**Approach:**
- Begin with the desired reaction and rearrange the known reactions, applying the principles of thermochemistry, to solve for the unknown enthalpy change.](/v2/_next/image?url=https%3A%2F%2Fcontent.bartleby.com%2Fqna-images%2Fquestion%2F54e7981d-d827-4f19-ae94-405462a85087%2F5a02df29-b4ce-4f7e-b1f1-11bb47ca29c8%2Fo2zrwqc_processed.png&w=3840&q=75)
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