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
Electron affinity
The enthalpy change when one mol of gaseous atoms gain electrons to form one mol of negatively charged ions
Rate of a reaction
The change in concentration of products/reactants per unit time. Usually measured in mol * dm^-3 * s^-1.
Activation energy
The minimum energy needed for a a reaction to occur. Measured in kJ / mol
Brønsted-Lowry acid
A proton donor
Brønsted-Lowry Base
A proton acceptor
Lewis acid
An electron pair acceptor
Lewis base
An electron pair donor
Oxidation
Loss of electrons
Reduction
Gain of electrons
Oxidising agent
A species that accepts electrons from a compound undergoing oxidation. The oxidising agent itself is being reduced
Reducing agent
A species that donates electrons to a compound undergoing reaction. The reducing agent itself is being oxidised
Standard electrode potential (E)
The electrode of a voltaic cell as measured compared to the standard hydrogen electrode
