Page 11 - Fuel Cell Student Edition

The next figure compares the efficiencies of This means that the product cannot be split into the
common fuel cells. Note that nuclear power
has the highest efficiency of any known energy
source. Magnesium-Air Fuel Cells are very
efficient, but they need to be cleaned regularly
and the magnesium gets used up very quickly. The
electrolyte also becomes contaminated over time. In
this lab you will build a zinc-air cell and learn first- product side of the equation because of the Law of
hand the challenges facing researchers attempting
to commercialize them.
Before analyzing the alkaline fuel cell in
more depth, it is important to understand the
fundamentals of how chemical equations are
written. They consist of two parts: reactants and
products. The reactants are starting components
that interact to form the final products.
In a chemical equation symbols describe the
reaction that occurs such as the “ ” symbol which
denotes an irreversible net forward reaction.
10 TOTAL REDOX™ – FUEL CELLS
reactants, but the reactants can form the product.
The “ ” symbol denotes a reversible reaction.
With all chemical reactions the type and number
of elements on the reactant side of the equation
must equal the type and number of elements on the
Conservation of Mass. This is achieved through
the use of coefficients which balance the chemical
equation by indicating multiples of the molecule the
coefficient precedes. [7]
Charged atoms and molecules are denoted by
an exponent after them. A plus sign indicates
a positively charged cation and a minus sign
indicates a negatively charged anion.
Oxidation-reduction reactions occur in all fuel cells.
These reactions are more commonly referred to
as redox reactions. [8] An example of a redox
TOTAL REDOX™ – FUEL CELLS 11