standard enthalpy change of combustion
the enthalpy/energy change when one mole of a substance
is burned in an excess of air/oxygen or completely combusted
under standard conditions
the minimum energy required
in order for the reaction to take place
A proton(H+) donor
(an acid that is) partially / incompletely ionised/ dissociated
an equilibrium which forward reaction rate quals backward reaction rate or forward/back reactions occurring but concentrations of all species do not change
atoms with the same number of protons
but different number of neutrons
(an acid that is) completely ionised/ dissociated
relative atomic mass
average mass of an atom of an element
compared with C -12
one atom of C-12 has a mass of exactly 12
chiral centre is a carbon atom that bonds to four different groups or atoms
first ionisation energy
Energy required to remove one mole of electrons
from one mole of gaseous atoms of an element
Relative isotopic mass
Mean/average mass of an atom relative to 1/12 the mass of an atom of C-12
Atoms with the same number of protons and different number of neutrons
Proton number or number of protons
Nucleon number; total number of protons and neutrons
First ionisation energy
The amount of energy required to remove one electron from each atom in one mole of atoms of the element in the gaseous state (to form gaseous 1+ ions).
Attraction/attractive force between positively and negatively charged ions in an ionic lattice.
Attraction between nucleus and shared pair of electrons.
Dative covalent bonding
One atom provides both electrons in the formation of the covalent bond.
Sigma bond (σ bond）
Sigma bonds are formed by end-on overlap of atomic orbitals.
Pi bond (Π bond）
Pi bonds are formed by sideways overlap of p-type atomic orbitals.