Definitions Flashcards
Define the mass number of an atom.
The number of protons + the number of neutrons
Define relative atomic mass of an element.
The average mass of an atom of an element
Compared to 1/12th the mass of a carbon-12 atom
Define the term enthalpy change
Heat change at a constant pressure
Define the term enthalpy change of combustion
The energy change when one mole of fuel is burned completely in oxygen in standard states and conditions.
Define the term enthalpy change of formation
The energy change when one mole of product is formed from its constituent elements in standard states and conditions
Define the first ionisation energy of an element.
The enthalpy change when removing one mole of electrons from one mole of gaseous atoms to form one mole of positive ions
Define the atomic number of an element
The number of protons in the nucleus of an atom
Define the term electron affinity of an element.
The enthalpy change from the formation of one mole of negative ions from one mole of atoms in a gaseous state
Define the term enthalpy of hydration of an ion
The enthalpy change when one mole of gaseous ions forms aqueous ions
Define the term lattice enthalpy of dissociation
The enthalpy change when separating one mole of an ionic solid into its gaseous ions
Define the term perfect ionic model
Only ionic bonding, no covalent bonds, ions are point charges, ions are spherical
Define the term enthalpy change of solution
The enthalpy change when one mole of an ionic substance dissolves in water to give a solution of infinite dilution
Define the term lattice enthalpy of formation
The enthalpy change when forming one mole of ionic solid from its separated gaseous ions
Define the term enthalpy of atomisation
The enthalpy change when one mole of gaseous atoms is formed from the element in standard states under standard conditions
Define the term electronegativity
The ability of an atom to attract the pair of electrons in a covalent bond
