AL Vocabulary Flashcards
acid-base indicator
a substance that changes colour over a narrow range of pH values
acid dissociation constant, Ka
the equilibrium constant for a weak acid
Ka = [H+][A-] / [HA]
activation energy
the minimum energy that colliding particles must possess for a successful collision that results in a reaction to take place
active site (of an enzyme)
the ‘pocket’ on an enzyme surface where the substrate binds and undergoes catalytic reaction
acyl chloride
a reactive organic compound related to a carboxylic acid, with the OH group in the acid replaced by a Cl atom, e.g. CH3COCl
addition polymerisation
the reaction in which monomers containing carbon-to-carbon double bonds react together to form long-chain molecules called polymers
addition reaction
an organic reaction in which two reactant molecules combine to give a single product molecule
adsorption (in catalysis)
the first stage in heterogeneous catalysis - molecules of reactants (usually gases) form bonds with atoms on the surface of the catalyst
Allotrope
Different crystalline or molecular forms of the same element. Graphite and diamond are allotropes
Alloy
A mixture of two or more metals or a metal with a non-metal
Amino acid residue
An amino acid unit within a polypeptide chain
Amphoteric
Able to behave as both an acid and a base. Aluminium oxide is amphoteric
Arene
Hydrocarbon containing one or more benzene rings
Atomic orbitals
Regions of space outside the nucleus that can be occupied by one or, at most, two electrons. Orbitals are named s, p, d, f. They have different shapes
Average bond energy
A general bond energy value used for a particular bond, when exact bond energy is not required. Strength of bond is slightly different in different compounds, depending on the environment of the bond
