Definitions Flashcards
Define Relative atomic mass
Mean mass of an atom relative to 1/12th the mass of an atom of carbon-12
Relative Molecular mass
Mean mass of a molecule relative to 1/12th the mass of an atom of carbon-12
Relative isotopic mass
The mass of one atom of an isotope relative to 1/12th of the mass of an atom of carbon-12
First ionisation energy
Energy required for the removal of one mole of electrons from one mole of atoms to form one mole of gaseous 1+ ions
Orbital
A volume of space where there is a high chance of finding an electron. Orbitals contain 2 electrons that spin in opposite directions
Ionic bonding
The strong electrostatic attraction between oppositely charged ions
Covalent bond
Strong electrostatic attraction between two nuclei and the shared pair of electrons between them
Electronegativity
The power of an atom to attract the bonding pair of electrons in a covalent bond
Metallic bonding
The strong electrostatic attraction between metal ions and delocalised electrons
What is a Dative/Coordinate Bond
Both electrons in a covalent bond come from one atom
Define Oxidation number
An oxidation state/number shows the charge on an atom if all of its bonds were considered totally ionic
What is disproportionation
An element in a single species is simultaneous oxidised and reduced
Define enthalpy change
Enthalpy change is the heat change in a reaction at constant pressure
What are standard conditions for pressure and temperature
100 kPa and 298 K
Define enthalpy change of reaction
Enthalpy change of a reaction according to the molar quantities in the equation under standard conditions
Define enthalpy change of formation
Enthalpy change when one mole of substance is formed from elements in their standard states under standard conditions
Define enthalpy change of combustion
Enthalpy change when one mole of substance completely combusts in oxygen to form CO2 and H2O under standard conditions
Define enthalpy change of neutralisation
The enthalpy change when and acid and alkali react to form 1 mole of water under standard conditions
Define bond enthalpy
Energy required to break one mole of a bond type in a molecule in the gaseous state
Define dynamic equilibrium
Rate of forwards and backwards reaction is the same. Concentration of reactants and products are constant
Define lattice enthalpy of formation
Enthalpy change when 1 mole of a solid ionic compound is formed from its gaseous ions under standard conditions
Define enthalpy change of atomisation with an example equation for Fluorine
The enthalpy change when 1 mole of gaseous atoms is made from an element in its standard state
1/2 F2 (g) —-> F(g)
Define first electron affinity
The enthalpy change when 1 mole of gaseous 1- ions are made from 1 mole of gaseous atoms.
Define 2nd electron affinity
The enthalpy change when 1 mole of gaseous 2- ions are made from 1 mole of gaseous 1- ions
