Chem Defiintions

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Carys

Cards (86)

Relative Atomic Mass 
The weighted mean mass of an atom of an element relative to 1/12 of the mass of one atom of carbon-12
First Ionisation energy 
The energy required to remove an electron from each atom in one mole of gaseous atoms
Bronsted-Lowry acid 
A species that is a proton donor
Activation Energy 
The minimum energy required to start a reaction by the breaking of bonds
Addition Polymerisation 
Formation of a very long molecular chain, by repeated addition reactions of many unsaturated alkene molecules (monomers).
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 solid is held to the surface of a solid, or, more rarely, a liquid
Alicyclic 
Containing carbon atoms joined together in a ring that is not aromatic
Aliphatic 
Containing carbon atoms joined together in straight or branched chains
Alkali 
A type of base that dissolves in water forming hydroxide ions
Alkanes 
The homologous series with the general formula CnH2n+2
Amount of Substance 
The quantity whose unit is the mole
Anhydrous 
A substance containing no water molecules
Alkyl Group 
A side chain formed by removing a hydrogen atom removed from an alkane parent chain, for example, CH3, C2H5; any alkyl group is often shown as R.
Anion 
A negatively charged ion
Atom Economy 
(molecular mass of the desired product/sum of molecular masses of all products) x100
Atomic Orbital 
A region within an atom that can hold up to two electrons, with opposite spins
Atomic Number 
The number of protons in the nucleus of an atom
Mean bond enthalpy 
The enthalpy change when one mole of gaseous molecules each breaks a covalent bond to form two free radicals, averaged over a range of compounds
Avogadro Constant 
The number of atoms per mole of the carbon-12 isotope. (6.02 x 10^23)
Base 
A compound that neutralises an acid to form a salt.
Biodegradable Material 
A substance that is broken down naturally in the environment of a living organism
Carbanion 
An organic ion in which a carbon atom has a negative charge
Carbocation 
An organic ion in which a carbon ion has a positive charge.
Catalyst 
A substance that changes the rate of a chemical reaction without it being used up
Cation 
A positively charged ion
Coordinate Bond 
A shared pair of electrons which has been provided by one of the bonding atoms only; also called a dative covalent bond.
Covalent Bond 
A shared pair of electrons
Cracking 
The breakdown of long-chained saturated hydrocarbons to form a mixture of shorter-chained alkanes and alkenes
Curly Arrow 
A symbol used in reaction mechanisms to show the movement of an electron pair in the breaking or formation of the molecule
Dative Covalent Bond 
A shared pair of electrons which has been provided by one of the bonding atoms only; also called a coordinate bond.
Dehydration 
An elimination reaction in which water is removed from a saturated molecule to make an unsaturated molecule
Delocalised Electrons 
Electrons that are shared between more than two atoms
Displacement Reaction 
A reaction in which a more reactive element displaces a less reactive element from an aqueous solution of the latter's ions
Displayed Formula 
A formula showing the relative positioning of all the atoms in a molecule and the bonds between them
Disproportionation 
A redox reaction in which the same element is both oxidised and reduced
Dynamic Equilibrium 
The equilibrium that exists in a closed system when the rate of the forward reaction is equal to the rate of the reverse reaction and concentrations do not change
E/Z Isomerism 
A type of stereoisomerism in which different groups attached to each carbon of a C=C double bond may be arranged differently in space because of the restricted rotation of the C=C bond
Electron Configuration 
A shorthand representation that shows how electrons occupy sub-shells in an atom
Electronegativity 
A measure of the attraction of a bonded atom for the pair of electrons in a covalent bond