Definitions Flashcards
Relative Molecular mass (Mr)
Mass of a molecule relative to a molecule of Carbon 12 (Add up the ‘Ar’ for all atoms involved in the molecule)
Relative atomic mass (Ar)
Shows the mean mass of all naturally occuring isotopes of an element relative to 1/12 of a C-12 at.
Mass Number (A)
Total number of all protons and neutrons in the nucleus of an atom
Atomic Number (Z)
Total number of protons in the nucleus of an atom
First ionization energy
Minimum energy required to takeaway one mole of electrons from one mole of an element in its gaseous state to form one mol of gaseous ions
Electronegativity
Ability of an atom to attract a shared pair of electrons (covalent bond) towards itself
Ligans
A species with a lone pair of electrons that can donate one non-boding pair of electrons to form a dative covalent bond with ions of transition metals
Standard enthalpy change (Delta H)
Heat energy transferred under standard conditions.
Exothermic reactions
A reaction where heat is given off to the surroundings. Delta H is negative
Endothermic reaction
A reaction where heat is absorbed from the surroundings. Delta H is positive.
Average bond enthalpy
The energy required to break one mol of a specific type of bond. Measures as an average over several similar molecules
Standart state
The state of an element at 298K and 101.3 kPa (1atm)
Standart enthalpy change of formation (Delta Hf)
The enthalpy change involved in the formation of 1 mole of a compound in its standard change out of its elements in their standard state
Standard enthalpy change of combustion (Delta Hc)
The enthalpy change involved in the complete combustion of one mole of a compound from its standart state
Lattice enthalpy. (Delta Hlat)
The enthalpy change involved in the conversion of one mole of a solid compound into gasous ion
