Deterioration of buildings, bridges, and other structures through the rusting of iron costs millions of dollars every day. Although the actual process also requires water, a simplified equation (with rust shown as Fe₂O3) is: ΔΗ,xn 4 Fe(s) + 3 O₂(g) - > 2 Fe₂O3(s) (a) What is the AHrxn when 0.250 kg of iron rusts? x 10 kJ x 10 (b) How much rust forms when 7.90 × 10³ kJ of heat is released? = -1.65 × 10³ kJ g Fe₂O3
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.
![Deterioration of buildings, bridges, and other structures through the rusting of iron costs millions of
dollars every day. Although the actual process also requires water, a simplified equation (with rust
shown as Fe₂O3) is:
ΔΗ,xn
4 Fe(s) + 3 O₂(g) - > 2 Fe₂O3(s)
(a) What is the AHrxn when 0.250 kg of iron rusts?
x 10
kJ
x 10
(b) How much rust forms when 7.90 × 10³ kJ of heat is released?
= -1.65 × 10³ kJ
g Fe₂O3](/v2/_next/image?url=https%3A%2F%2Fcontent.bartleby.com%2Fqna-images%2Fquestion%2F15c022aa-6711-4b29-ab7f-4e5d70ca82f7%2F61752d00-92b9-4748-af4c-7d1fc0016a54%2Futprhr7_processed.png&w=3840&q=75)
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