Definitions Flashcards
Relative isotopic mass
mass of an atom of isotope relative to 1/12 of the mass of an atom of 12C.
Relative atomic mass
average mass of an atom of an element relative to 1/12 of the mass of an atom of 12C
Relative molecular mass
average mass of one molecule of a substance relative to 1/12 of the mass of an atom of 12C
Relative formula mass
mass of one formula unit of a substance relative to 1/12 of the mass of one atom of 12C
Mole
one mole is the amount of substance that contains 6.02x10^23 particles
Disproportionation reaction
redox reaction in which one species is simultaneously oxidized and reduced
Mass number/nucleon number
total number of protons and neutrons in an atom
Proton number
Number of protons in the nucleus of an atom
Isotopes
Atoms of the same element with same number of protons but different number of neutrons
First ionization energy
The energy absorbed to remove one mole of electrons from one mole of gaseous atoms to form one mole of singly charged positive gaseous ions.
Electronegativity
measure of the ability of an atom in a molecule to attract the shared pair of electrons in a covalent bond.
Ionic bond
strong electrostatic attraction between oppositely charged ions formed by the transfer of electrons between the original atoms
Covalent bond
strong electrostatic attraction between the positive nuclei of the two atoms and the bonding electrons shared between them.
Dative/co-ordinate bond
covalent bond in which both electrons come from the same atom
Metallic bond
strong electrostatic forces of attraction between metal cations and mobile sea of delocalized electrons.
Bond energy
Energy is absorbed when one mole of a given covalent bond in a gaseous compound is broken into gaseous atoms or molecules
Lattice energy
Energy released when one mole of ionic solid is formed from its constituent gaseous ions.
Hess’ Law
Enthalpy change for a reaction is the same whether the reaction takes place in one step or in a series of steps and is determined by the initial and final states of the system.
Standard Enthalpy Change of Formation
The energy change when one mole of substance is formed from its constituent elements in their standard states at 298 K and 1 bar.
Standard Enthalpy Change of Combustion
The energy evolved when one mole of substance is burnt completely in excess oxygen at 298 K and 1 bar.
Standard Enthalpy Change of neutralisation
The energy evolved when one mole of water is formed in the reaction between an acid and a base at 298 K and 1 bar.
Rate equation
mathematical relationship between the reaction rate and the
concentration of the individual reactants.
Rate constant
proportionality constant for a given reaction at a certain temperature
Order of reaction
power to which that reactant’s concentration is raised to in an experimentally determined rate reaction
Overall order of reaction
sum of the individual orders of reaction with respect to all the reactants
Dynamic equillibrium
reversible process at equilibrium in which the rate of the forward reaction equals to the rate of backward reaction, with the concentrations of reactants and products remaining constant over time.
Buffer solution
a solution containing a weak acid and its conjugate base or a weak base and its
conjugate acid which resists and does not show significant changes in pH when small amount of strong acid or strong base are added to it.
Constitutional isomer
Compounds with same molecular formula but different structural formula
Stereoisomerism
compounds have the same molecular formula and the same structural formula, but the atoms in the molecules have different spatial arrangements.
Cis-trans isomerism
Restricted rotation about the Carbon double bond
The 2 groups bonded to each carbon in the C=C bond must not be identical.
Polymer
macromolecule built up from monomers, with average molar mass of at least 1000 or at least 100 repeat units.
Nanomaterial
Material with at least one dimension on the nanoscale (1-100nm)
Nanoparticle
Material with all three dimensions on the nanoscale (1-100nm)
