Use average bond enthalpies from the table to estimate AH for the following gas-phase reaction of ethylene, (C₂H4), oxygen, and hydrogen to form ethylene glycol (C₂H6O2), which is the principal component of automotive antifreeze: H H H H + O=O + H―H →→→→ HH H-O-C-C-O-H H H Express the enthalpy change with the appropriate units.
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.
![### Problem 5.115
**Average bond enthalpies of some bonds are given in the table below:**
| Bond | Average Bond Enthalpies (kJ/mol) |
|--------|----------------------------------|
| C–C | 348 |
| C=C | 614 |
| C–H | 413 |
| O=O | 495 |
| H–H | 436 |
| H–O | 463 |
| C–O | 358 |
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### Part A
Use average bond enthalpies from the table to estimate \( \Delta H \) for the following gas-phase reaction of ethylene (\( \text{C}_2\text{H}_4 \)), oxygen, and hydrogen to form ethylene glycol (\( \text{C}_2\text{H}_6\text{O}_2 \)), which is the principal component of automotive antifreeze:
#### Reaction:
\[
\text{C}_2\text{H}_4 + \text{O}= \text{O} + \text{H}–\text{H} \rightarrow
\]
\[
\text{H}–\text{O}–\text{C}–\text{C}–\text{O}–\text{H}
\]
**Diagram Explanation:**
- The starting materials are ethylene (\( \text{C}_2\text{H}_4 \)), oxygen (O=O), and hydrogen gas (H–H).
- The product is ethylene glycol (\( \text{H}–\text{O}–\text{C}–\text{C}–\text{O}–\text{H} \)).
**Instruction:**
Express the enthalpy change with the appropriate units.
\[ \Delta H = \text{Value} \, \text{Units} \]
*Submit your answer to the box provided.*
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**Note:** The reaction and bond formations require breaking and forming various bonds. Use the table to calculate the bond enthalpy changes associated with this process.](/v2/_next/image?url=https%3A%2F%2Fcontent.bartleby.com%2Fqna-images%2Fquestion%2Fecea1622-691a-42a4-89af-7d9492083764%2Fd47aeab1-0e51-4bdc-8bf5-a7ede76ae55d%2Fslqhg2f_processed.jpeg&w=3840&q=75)
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