A2 Chemistry Definitions Flashcards
Acid-base pair
A pair of two species that turn into each other through either losing or gaining a proton
Activation energy
The minimum level of energy needed to start a reaction by breaking bonds
Addition polymer
A very long molecular chain that is formed by repeated addition reactions of many monomers (unsaturated alkene molecules)
Addition reaction
A reaction in which a reactant is added to an unsaturated molecule to make a saturated molecule
Adsorption
The process that occurs when a gas, liquid or solute is held to the surface of a solid or less commonly a liquid
Alicyclic hydrocarbon
A hydrocarbon that has carbon atoms joined together in a ring formation
Aliphatic hydrocarbon
A hydrocarbon that has carbon atoms joined together in either straight or branched chains
Alkali
A type of base that dissolves in water to form hydroxide ions (OH-)
Alkanes
The homologous series with the general formula CnH2n+2
Alkyl group
An alkane with a hydrogen atom removed
Amount of substance
The mole. The amount of substance is the means by which chemists can count atoms
Anhydrous
A substance that contains no water molecules
Anion
A negatively charged ion
Atom economy
The molecular mass of the desired product divided by the sum of the molecular masses of all the products x100%
Atomic number
The number of protons in the nucleus of an atom
Atomic orbital
A region within an atom that can hold up to two electrons with opposite spins
Avogadro’s constant (N A)
6.02 x10 23mol-1
Biodegradable substance
A substance that can be broken down naturally in the environment by other living organisms
Biodegradable polymer
A polymer that breaks down completely into CO2 and H2O
Boltzmann distribution
A diagram that shows the distribution of the energies of the molecules at a particular temperature
Bronsted-Lowry acid
A species that is a proton donor, H+
Bronsted-Lowry base
A species that is a proton acceptor, H+
Buffer solution
A substance that reduces the difference in pH when small volumes of either acid or base are added to a solution
Carbanion
An organic ion in which a carbon atom has a negative charge
Carbocation
An organic ion in which a carbon atom has a positive charge
Catalyst
A substance that speeds up a chemical reaction without being used up itself
Cation
A positively charged ion
Chiral carbon
A carbon atom that is attached to four other different atoms or groups of atoms
Complex ion
A transition metal ion bonded to one or more ligands by coordinate bonds
Ligands
An ion or molecule that binds to a central metal atom to form a complex
Coordinate bonds
A covalent bond in which both electrons come from the same atom. Also known as a dative bond.
Concentration
The amount of solute in moles per 1000cm3 of solution
Condensation reaction
A reaction where two small molecules react together to form a bigger molecule releasing small molecules such as water
Conjugate base
A species formed when a proton is added to a base
Conjugate acid
A species formed when a proton is added to an acid
Coordination number
the total number of coordinate bonds that have formed between the central metal ion and any ligands
Covalent bond
A bond formed by a shared pair of electrons
Cracking
The breaking down of long chain saturated hydrocarbons to form a mixture of short chained alkenes and alkanes
Curly arrow
A symbol used in reaction mechanisms to the movement of an electron pair during the breaking or formation of a covalent bond
Dative covalent
A bond in which the pair of electrons are shared within the one atom only
Degradable polymer
A polymer that breaks down into smaller pieces when exposed to light, heat or moisture
Dehydration
An elimination reaction whereby water is removed from a saturated molecule to form an unsaturated molecule
