Flashcards in Defintions Deck (61):
The amount of any substance containing as many particles as there are carbon atoms in exactly 12 grams of the carbon 12 isotope.
Positively charged nucleus containing most of the mass, surrounded by atomic shells with orbiting electrons of negative charge and negligible mass.
An atom of the same element with the same number of protons (electrons) but a different number of neutrons.
Proton donors. When they’re in water they release H+ ions into the solution.
A soluble base which releases OH- ions in solution.
Proton acceptors, they take H+ ions and neutralise acids
A product of when an H+ ion is replaced by a metal ion.
A substance containing no water molecules.
A crystalline compound containing water molecules.
Define first ionisation energy
The energy required to remove one electron from the outer shell from one mole of gaseous atoms to form one mole of gaseous 1+ ions.
Define second ionisation energy
The energy required to remove one electron from the outer shell from one mole of gaseous 1+ ions to form one mole of gaseous 2+ ions.
Define nuclear charge
The attraction from the protons in the nucleus with electrons.
A region that can hold up to two electrons of opposite spins (Up and down).
Define covalent bonding
A bond formed when atoms share pairs of electrons.
Define dative covalent bonding
A bond formed when one of the bonding atoms gives both of a pair of electrons.
The ability of an atom to attract the bonding electrons in a covalent bond.
Define relative atomic mass
Average weighted mass of an atom compared with 1/12th of the mass of an atom of Carbon-12.
Define relative isotopic mass
Mass of an atom of an isotope compared with 1/12th of the mass of an atom of Carbon-12.
Define standard enthalpy of formation
The standard enthalpy change of formation of a compound is the enthalpy change which occurs when one mole of the compound is formed from its elements under standard conditions, and with everything in its standard state.
Define standard enthalpy of combustion
The standard enthalpy change of combustion of a compound is the enthalpy change which occurs when one mole of the compound is burned completely in oxygen under standard conditions, and with everything in its standard state.
Define standard enthalpy of neutralisation
The standard enthalpy change of neutralisation is the enthalpy change when solutions of an acid and an alkali react together under standard conditions to produce 1 mole of water.
Define standard enthalpy of reaction
The standard enthalpy change is the enthalpy change that occurs in a reaction in molar quantities shown in a chemical equation under standard conditions.
Define average bond enthalpy
The energy required to break one mole of a specified type of bond in a gaseous molecule.
Define Hess' law
If a reaction can take place by two routes and the starting and finishing conditions are the same, the total enthalpy change is the same for each route.
Define activation energy
The minimum energy required for a reaction to occur.
Define specific heat capacity
The energy required to raise the temperature of 1 gram of a substance by 1 Kelvin.
It is an electron pair acceptor.
It is an electron pair donor.
Define ionic bond
Oppositely charged ions held together in a crystal lattice by electrostatic attraction.
Define lattice enthalpy
The enthalpy change that occurs when 1 mole of a solid ionic compound is formed from its gaseous ions under standard conditions.
Define standard enthalpy of solution
The enthalpy change that occurs when 1 mole of solute is completely dissolved in the solvent under standard conditions.
Define standard enthalpy of hydration
The enthalpy change that occurs when 1 mole of isolated gaseous ions are dissolved in water forming 1 mole of aqueous ions under standard conditions.
Define transition element
A metal atom with partially filled d orbitals as it forms an ion.
An atom/molecule/ion that can donate a pair of electrons to a metal ion to form a dative covalent bond.
Define buffer solution
A system, containing a weak acid and its conjugate base, that minimises pH change when a small amount of acid/alkali is added.
Small molecules that are part of a long chain of monomers.
Long chain molecules with monomers joined together.
Define addition polymerisation
The formation of a large chain of monomers through the rearrangement of bonds of smaller monomers.
Define condensation polymerisation
The formation of one large polymer from many small monomer molecules joining together, with water, or some other small molecule formed at the same time.
Same structural formula but different arrangement in space.
The optical isomer of the same molecule.
A substance that increases the rate of a chemical reaction by providing alternate routes without itself undergoing any permanent chemical change.
Define homogeneous equilibrium
The reactants and products at equilibrium are all in the same state.
Define heterogeneous equilibrium
The reactants and products are in different states.
Define the equivalence point of titration
The volume of one substance that exactly reacts with another.
Define the end point of a titration
Concentrations of HA and A are equal.
Define standard electrode potential
The potential difference of a half cell compared with a standard hydrogen half cell, measured at 298K with solution concentrations of 1 mol dm^-3 and a gas pressure of 100kPa
A molecule/ion that has separate groups of negative and positive charge.
Define isoelectric point
The pH at which zwitterion exists.
Define optical isomerism
Non-superimposable mirror images of the same molecule.
Define molecular ion
An unfragmented ion with positive charge.
A molecule that contains at least one unpaired electron.
Define spin-spin coupling
When the hydrogen peak is split from the influence of hydrogen atoms attached to the neighbouring carbons.
Define complex ion
A metal ion at the centre with a number of other molecules or ions surrounding it attached to the central ion by co-ordinate (dative covalent) bonds.
Define functional group
A part of an organic molecule that is largely responsible for the molecule's chemical properties.
Define empirical formula
The simplest whole number ratio of atoms of each element present in a compound
Define molecular formula
The number and type of atoms of each element in a molecule
Define general formula
The simplest algebraic formula for any member of the homologous series
Define homologous series
A series of compounds with the same functional group and similar chemical properties.
Define homolytic fission
A chemical reaction in which the breaking of bonds yields molecular fragments each having one unpaired electron.