Definitions Flashcards
(23 cards)
Enthalpy of Hydrogenation
Enthalpy change when one mole of a double c bond reacts with hydrogen
Hydration Enthalpy
The standard Enthalpy change when one mole of gaseous ions is converted to 1 mole of aqueous ions
E.g Na+(g) + aq —-> Na+(aq)
Enthalpy of formation
The Enthalpy change when one mole of a compound is formed from its constituents elements in their standard states under standard conditions
E.g C(s) + 2H2(g) —-> CH4(g)
Enthalpy of combustion
Enthalpy change when one mole of a compound in its standard state burns in excess oxygen under standard conditions
E.g C(s) + O2(g) —-> CO2(g)
Mean bond Enthalpy
Enthalpy change required to break 1 mole of a covalent bond into gaseous atoms, made average over a range of different compounds
E.g Cl2(g) —-> 2Cl(g)
Ionisation energy
Ionisation energy is the amount of energy needed to remove a mole of electrons from a mole of atoms, in the gaseous state.
E.g Na(g) —-> Na+(g) + e-
Electronegativity
Power of an electron to attract a pair of electrons in a covalent bond
Relative atomic mass
Average mass of an atom of an element compared to 1/12th the mass of a carbon 12 atom
Relative molecular mass
Average mass of a molecule of an element compared to 1/12th the mass of a carbon 12 atom
Hess’s Law
The enthalpy change for a chemical reaction is the same regardless of the route taken from reactants to products.
Enthalpy of atomisation
The enthalpy change when one mole of gaseous atoms is formed from an element in its standard state.
E.g Na(s) —-> Na(g)
First Ionisation Enthalpy
The standard enthalpy change when one mole of electrons is removed from one mole of gaseous atoms to give one mole of gaseous ions with a single positive charge.
E.g Na(g) —-> Na+(g) + e-
Second Ionisation Enthalpy
The standard enthalpy change when one mole of electrons is removed from one mole of gaseous 1+ ions to give one mole of gaseous ions each with a 2+ charge.
E.g Ca+(g) ——> Ca2+(g) + e-
First Electron Affinity
The standard enthalpy change when one mole of gaseous atoms is converted into a mole of gaseous ions each with a single negative charge under standard conditions
E.g Cl(g) + e- —-> Cl-(g)
Second Electron Affinity
The standard enthalpy change when one mole of electrons is added to a mole of gaseous ions each with a 1- charge to form a mole of ions each with a 2- charge
E.g O-(g) + e- —-> O2-
Lattice Formation Enthalpy
The standard enthalpy change when one mole of solid ionic compound is formed from its gaseous ions.
E.g Na+(g) + Cl-(g) ——> NaCl(s)
Lattice Dissociation Enthalpy
The standard enthalpy change when one mole of solid ionic compound dissociates into its gaseous ions.
E.g NaCl(s) —-> Na+(g) + Cl-(g)
Standard Enthalpy of Solution
The standard enthalpy change when one mole of solute dissolves in enough solvent to form a solution in which the ions are far enough apart not to interact with each other.
E.g NaCl(s) + aq —-> Na+(aq) + Cl-(aq)
Periodicity
Repeating patterns in chemical and physical properties
Transition metals
A transition metal is one which forms atleast one stable ion with a partially filled d sub shell
Ligand
Ion or molecule with a lone pair of electrons which can form a coordinate bond with a transition metal ion
Bidentate ligand
2 atoms that each donate a lone pair of electrons
Chelate effect.
When a monodentate ligand is substituted for a bi and multi dentate ligand
