If the first, second and third bond dissociation enthalpies of methane are +420, +475, and +421 KJmol-l, respectively, calculate the fourth. How do you account for the fact that; ammonium nitrate is readily soluble in water even though the standard enthalpy of solution has a positive value? although the enthalpy of combustion of cane sugar is about -6000 KJmol-l cane sugar is not observed to oxidise in air at ordinary temperature?
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.
If the first, second and third bond dissociation enthalpies of methane are +420, +475, and +421 KJmol-l, respectively, calculate the fourth.
How do you account for the fact that;
ammonium nitrate is readily soluble in water even though the standard enthalpy of solution has a positive value?- although the enthalpy of combustion of cane sugar is about -6000 KJmol-l cane sugar is not observed to oxidise in air at ordinary temperature?
![ii)
Given the following standard enthalpies of combustion,
AH"c [C2H50H] = 1371 KJmol".
AH c[CH3CH0] = - 1167 KJmol.
Calculate the standard enthalpy change for the oxidtion of ethanol to ethanal.](/v2/_next/image?url=https%3A%2F%2Fcontent.bartleby.com%2Fqna-images%2Fquestion%2F6dd75185-b23a-4c7a-b6dd-7305d1ec9c32%2Fb5e02ea8-496a-44e6-bb16-866faf5bc7e0%2F51cemmk_processed.jpeg&w=3840&q=75)
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