Increasing a reaction rate by adding a substance (the catalyst) not permanently changed by the
reaction. The catalyst lowers the activation energy.
Catalyst
A substance that increases the rates of the forward and reverse directions of a specific reaction but
is itself left unchanged.
Cathode
The electrode at which reduction takes place.
Cation
An ionic species with a positive charge.
Celsius (°C)
A temperature scale defined by having 0°C equal to the freezing point of water and 100°C equal to
the boiling point of water; also the units of that scale. Otherwise known as the centigrade
temperature scale. 0°C = 273.15K.
Charles’s law
The law stating that the volume of a gaseous sample at constant pressure is directly proportional to
its absolute (Kelvin) temperature.
Chemical bond
The interaction between two atoms resulting from the overlap of electron orbitals, holding the two
atoms together at a specific average distance from each other.
Chemical properties
Those properties of a substance describing its reactivity.