GUIDE QUESTIONS: 1. Calculate the heat of combustion of the following reactions (sh ow the computation) Use the enthalpy of formation of the substances given below: Substances CO2 (0) H2O Oz g) CH3CH2OH CH3(CH2)2OH CH3(CH2)»OH AH? (kJ/mal) -393.5 -285.8 -276.98 -303.3 -332.8 a. combustion of ethanol CH,CH2OH, + 3029) → 2CO29) + 3H2O) b. combustion of propanol CH:(CH2)OH) +4.5Oz19) → 3CO29) + 4H;O c. combustion of butanol CH:(CH2),OH + 602(9) → 4COzip) + 5H;O
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.
![GUIDE QUESTIONS:
1. Calculate the heat of combustion of the following reactions (show the computation).
Use the enthalpy of formation of the substances given below:
Substances
CO2 (a)
H2O )
AH? (k]/mol)
-393.5
-285.8
O2 ig)
CH3CH2OH
-276.98
CH3(CH2)2OH
CH3(CH2)»OH
-303.3
-332.8
a. combustion of ethanol
CH,CH2OH, + 30zig) → 2CO29) + 3H2Om
b. combu stion of propanol
CH3(CH2)OH, +4.5O2g)
3CO20) + 4H2O)
c. combu stion of butanol
CH:(CH,),OH + 60zg)
- 4COzp) + 5H;O](/v2/_next/image?url=https%3A%2F%2Fcontent.bartleby.com%2Fqna-images%2Fquestion%2F5a6d0db6-878b-4366-a19d-eb14d9867ef0%2Fcaba3d75-000a-4ddc-ad82-985077968bf9%2Fr0yy303_processed.png&w=3840&q=75)
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