Core
Energetics: Enthalpy
Slide 20 of 34
Thermochemistry
The examination of the relationships between chemical reactions and energy
changes is an aspect of chemistry called thermochemistry.
(or energetics)
Thermochemistry looks at performance of work (which has a
slightly different meaning in science), expenditure or consumption of
energy by chemicals, and flow of heat between different
chemical species.
For example, work must be performed to compress a gas or to separate particles
of opposite electrical charge (such as an electron and a nucleus).
Chemical processes such as the burning of gasoline release energy in
the form of heat.
Chemical systems perform work and transfer heat, which
essentially boils down to inter-conversion and/or changes in kinetic and potential
energy of the
substance(s) involved.
The broader topic of the study of energy and its
transformation is known as thermodynamics,
of which thermochemistry is only a small sub-topic.