definitions Flashcards
(23 cards)
Definition of first ionisation energy
energy required to remove one mole of electrons from one mole of gaseous atoms of an element to form one mole of gaseous ions under standard conditions
Definition of second ionisation energy
energy required to remove one mole of electrons from one mole of gaseous ions of an element to form one mole of gaseous 2+ ions under standard conditions
Defintion of electronegativity
The power of an atom to attract electrons to itself
Definition of average bond enthalpy
Average enthalpy change when one mole of bond is broken
Definition of enthalpy change of combustion
Energy change when one mole of substance is combusted
Racemic Mixture
A mixture that contains each optical isomer in a 50:50 ratio
Definition of relative molecular mass
Mass of a molecule relative to 1/12 of an atom of carbon 12
Two assumptions for ideal gas
Negligible volume of molecule
No intermolecular force
Two conditions for ideal gas
High temperature
Low Pressure
Definition of Rate of reaction
Change in amount of substance with time
Definition of empirical formula
the simplest whole number ratio of the elements present in one molecule
Definition of molecular formula
the formula that shows the number and type of each atom in a molecule
Define atomic mass unit
1/12 mass of a carbon -12
definition of enthalpy change of formation
enthalpy change when one mole of compound is formed from its constituent elements in their standard states under standard conditions
Definition of enthalpy change of neutralisation
The enthalpy change when solution of an acid and alkali react together under standard conditions to produce 1 mole of water
bond polarity
Unequal sharing of electrons between two atoms in a covalent bond due to a difference in electronegativity
dynamic equilibrium definition
A reaction where the rate of the forward reaction equals the rate of the reverse reaction, resulting no overall change in the concentrations of reactants and products in a closed system
Which two metals don’t follow the standard electronic configuration pattern and give their electronic configuration
Chromium and Copper
Cr: [Ar] 4s1 3d5
Cu: [Ar] 4s1 3d10
Electronic configuration of Cr 3+ and Cu 2+
Cr 3+: [Ar] 3d3
Cu 2+: [Ar] 3d9
Define bond energy
The energy required to break on mole of a particular covalent bond in the gaseous state
Define bond length
The internuclear distance of two covalently bonded atoms
Define Le Chatelier’s principle
If a change is made to a system at dynamic equilibrium, the position of equilibrium moves to minimise this change
