Important Definitions- LEARN Flashcards
ISOTOPES
Atoms of an element with the same atomic number but different numbers of neutrons.
RELATIVE ISOTOPIC MASS
The mass of an atom of an isotope relative to 1/12 the mass of a carbon 12 atom.
RELATIVE ATOMIC MASS
The wheighted average mass of an atom of an element relative to 1/12 the mass of a carbon 12 atom.
ORBITAL
Region around the nucleus where two electrons can be held with opposite spins.
ACID
Any species that can donate H+ ions.
BASE
Any species that can receive an H+ ion. This can be soluble or insoluble.
Alkali
Soluble species that can accept an H+ ion.
SALT
An ionic compound of anions and cations, forming a neutral compound.
WATER OF CRYSTALISATION
Water molecules are part of the crystal structure.
HYDRATED SALT
Water molecules are part of the crystal structure.
IONIC BONDING
The strong electrostaitic forces of attraction between two oppositely charged ions.
COVELANT BONDING
The strong electrostatic forces between a shared pair of electrons and the two positive nuclei of the bonded atoms.
DATIVE COVELANT BOND
When both shared electrons in a covelant bond come from the same atom.
AVAGADROS CONSTANT
6.02 x 10²³ , the number of particles in a mole.
MOLAR VOLUME
The volume per mole of gas molecules at a stated temperature and pressure.
MOLAR MASS
The mass of a substance per mole (measured in g mol-1)
MOLECULAR FORMULA
The actual number of atoms of each element in a molecule.
ATOM ECONOMY
The ratio of the mass of desired products to the mass of all the products. A measure of how well atoms have been utilised.
EMPIRICAL FORMULA
The simplist whole number ratio between the atoms of each element in a compound.
STRONG ACIDS VS WEAK ACIDs
- strong acids fully ionise (completely dissociates)
- weak acids partially ionise (partially dissociates)
ELECTRONEGATIVITY
The tendancy of an atom to attract a bonding pair of electrons in a covelant bond.
POLAR COVELANT BOND
A bonded electron pair is shared unequally between the bonded atoms because of the difference in electronegativity values of the bonded atoms.
DIPOLE
A molecule with separated areas of slightly negative and slightly positive charge.
OXIDATION NUMBER
Reprisents how many electrons lost or gained by an atom.
HOMOLOGOUS SERIES
Compounds from the same series with the same functional group but with each successive number differeing by CH
²
FUNCTIONAL GROUP
Part of the organic molecule responsible for its chemical reactions.
HYDROCARBON
Composed of only carbon and hydrogen atoms.
SATURATED
composed of only single c-c bonds
ALIPHATIC
Carbon atoms joined straight or branched, but with no rings.
ALICYCLIC
Molecule contains carbon atoms joined in a ring that is NOT AROMATIC.
AROMATIC
Molecule contains at least 1 benzene ring.
DISPROPORTIONATION
A redox reaction where the oxidation state of some atoms of a particular element increase, but the oxidation number of other atoms of that same element decrease.
RADICAL
Species with an unpaired electron.
HOMOLYTIC FISSION
A bond breaks leaving each atom one electron from the electron pair.
HETEROLYTIC FISSION
Bond breaks with one atom receiving both electrons from the electron pair.
STRUCTURAL ISOMER
Compounds with the same mollecular formula but different structural formula.
SIGMA BOND
overlapping of the 2 s orbitals from each bonding atom.
PI BOND
The sideways overlapp of 2 P orbitols, one from each bonded atom.
ELECTROPHILE
A species that accepts a pair of electrons to form a covelant bond.
NUCLEOPHILE
A species that can donate a pair of electrons to form a covelant bond
Average bond enthalpy
Energy required to break 1 mol of a specific type of bond in a gaseous molecules
Hess’s law
States that if a reaction can take place by 2 routes (and starting and finishing conditions are the same) the total enthalpy change is the same.
Enthalpy change of reaction
The enthalpy change that accompanies a reaction, in the molar quantities shown in a chemical equation, under stated conditions (with all products and reactants in standard states).
Enthalpy change of formation
The enthalpy change when one mole of a compound is formed from it’s elements (under stated conditions, with all reactants and products in their standard state).
Enthalpy of combustion
The enthalpy change that takes place when one mole of substance reacts completely with oxygen under stated conditions (with all reactants and products in their standard state).
Enthalpy change in neutralisation
The energy change that accompanies the reaction of an acid by a base to form one mole of water under stated conditions (with all reactants and products in their standard state).
FIRST IONISATION ENERGY
The energy required to remove an electron from each atom in a mole of gaseous atoms (to form 1 mole of gaseous 1+ ions).
Sterioisomers
Molecules with the same structural formulae but a different arrangement of atoms in space/ different 3D arrangement of atoms.
hygroscopic
absorbs moisture from air.
Enthalpy of atomisation
the enthalpy change that accompanies the formation if 1 mole of gaseous atoms from its elements in standard form.
lattice enthalpy of formation
the energy that accompanies the formation of 1 mole of an ionic compound from its gaseous ions under standard conditions.
First Electron Affinity
the enthalpy change when 1 electron is added to each atom in 1 mol of gaseous atoms to form 1 mole of gaseous 1- atoms.
second electron affinity
the enthalpy change when 1 electron is added from 1 mole of gaseous 1- ions to form 1 mole of gaseous 2- ions.
Hydration Enthalpy
the energy change when 1 mol of gaseous ions dissolve in water to make 1 mole of aqueous ions under standard conditions.
Enthalpy Of Solution
The enthalpy change when 1 mol of solute is dissolved in water under standard conditions.
reagent
a compound or mixture added to a chemical reaction to start or test a chemical reaction. can be used to determine the presence or absence of a specific chemical substance.
partial pressure
the contribution each gas in a mixture makes towards the total pressure of the container.
orders of reaction
the number /exponent that describes the effect that the concentration has on the initial rate of reaction.
Arrhenius Equation shows…
the exponential relationship between the rate constant K and temperature
ACID BASE CONJUGATE PAIRS
two species that can be interconverted by the transfer of a proton.
MONOBASIC, DIBASIC, TRIBASIC
number of hydrogen atoms in an acid that are replaced (per mol) in an acid - base reaction
Transition metals
an element whose atom has a partially filled d sub-shell, or which can give rise to cations with an incomplete d sub-shell. Have more than 1 oxidation state