What is Thermodynamics?
Thermodynamics is the
branch of science which studies the transformation of energy
from one form to another.
Chemical thermodynamics
looks at the energy transformations which occur as a result of
chemical reactions.
The questions that chemical thermodynamics asks are:
- How much heat is evolved during a chemical reaction ("thermochemistry")?
- What determines the direction of spontaneous chemical change?
For example, if you put a flame to a 2:1 mixture of
H2 and O2 there is an almighty bang and
the reaction proceeds spontaneously to products, i.e. without
any further supply of external energy.
Why does it not happen that water spontaneously goes to
H2 and O2 when we put a lit taper to
it under the same conditions?
- What determines the extent of chemical
change?
Not all reactions result in all of the reactants being
converted to products. Some reactions will proceed only so
far before the state of chemical equilibrium is achieved.
Chemical equilibrium is said to exist if no further tendency
for overall chemical change is observed - the ratios of the concentrations
of products to reactants remain fixed.
So chemical thermodynamics attempts to answer the important
question, "What determines the position of chemical equilibrium?".
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