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.
where did the 3.18 come from?
![Example 1: HF Buffer
In this example we will continue to use the hydrofluoric acid buffer. We will discuss the process for preparing a buffer of HF at a pH of 3.0. We can use the
Henderson-Hasselbalch approximation to calculate the necessary ratio of F and HF.
[Base]
pH = pKa + log
[Acid]
(5)
[Base]
3.0 = 3.18 + log
[Acid]
(6)
[Base]
log
[Acid]
= -0.18
(7)
[Base]
[Acid]
= 10-0.18
(8)
[Base]
[Acid]
= 0.66
(9)
This is simply the ratio of the concentrations of conjugate base and conjugate acid we will need in our solution. However, what if we have 100 ml of 1 M HF and
we want to prepare a buffer using NaF? How much Sodium Fluoride would we need to add in order to create a buffer at said pH (3.0)?](/v2/_next/image?url=https%3A%2F%2Fcontent.bartleby.com%2Fqna-images%2Fquestion%2F07bf12b2-af64-421d-af35-17a4b5703e0e%2Fbcaddf28-fccc-446a-8563-936e79beda81%2F1blxtv_processed.png&w=3840&q=75)
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