Keywords 2 Flashcards
Addition-elimination reaction
Occurs when two molecules join together, followed by the loss of a small molecule.
Adsorption
Process that occurs when reactants form weak bonds with a solid catalyst.
Amphoteric
A substance that can act as both an acid and a base.
Amphoteric behaviour
The ability of a species to react with both acids and bases.
Analyser
A material that allows plane-polarised light to pass through it.
Aromatic
The bonding in a compound with delocalised electrons forming pi bonding in a hydrocarbon ring.
Asymmetric
A carbon atom in a molecule that is joined to four different atoms or groups.
Autocatalysis
Occurs when the reaction product acts as a catalyst for the reaction.
Basicity
The extent to which a base can donate a lone pair of electrons to a hydrogen atom of a water molecule.
Bidentate ligand
One that forms two dative bonds with a metal ion.
Bimolecular
A mechanism that has two species reacting in a rate-determining step.
Buffer solution
A solution that minimises change in pH when a small amount of acid or base is added.
Chemical environments of carbon atoms in molecules
Related to whether the carbon atoms are identical or differently positioned in a molecule.
Chemical shift of a proton or group of protons
The number (ppm) that indicates its behaviour in a magnetic field relative to tetramethylsilane. Can be used to identify the chemical environment of the carbon atoms or of the hydrogen atoms (protons) attached to it.
Chiral
An atom in a molecule that allows it to exist in non-superimposable forms. Can also refer to the molecule itself.
Complex
Species containing a metal ion joined to ligands.
Condensation polymerisation
The formation of a polymer usually by the reaction of two different monomers and in which a small molecule is also formed.
Conjugate acid of the base
When a base accepts a proton, this species is formed.
Conjugate base of the acid
When an acid donates a proton, this species is formed.
Conjugate acid-base pair
Consists of either a base and its conjugate acid or an acid and it’s conjugate base.
Coordination number
The number of dative bonds in a complex.
Derivatives
Compounds formed from other compounds, especially when the properties of the derivative can be used to identify to original compound.
Desorption
Process that occurs when products leave the surface of a solid catalyst.
Electromagnetic spectrum
Range of all wavelengths and frequencies of all the types of radiation.
Electromotive force (emf)
The standard electrode potential of a half-cell connected to a standard hydrogen electrode. Measured under standard conditions: 298K, 100kPa and 1 mol dm-3.
Enantiomers
Isomers that are related as object and mirror image.
Enthalpy change of hydration
The enthalpy change when one mole of an ion in its gaseous state is completely hydrated by water.
Enthalpy change of solution
The enthalpy change when one mole of an ionic solid dissolves in water to form an infinitely dilute solution.
Entropy
A property of matter that is associated with the degree of disorder, or degree of randomness, of the particles.
Equivalent protons
Hydrogen atoms in the same chemical environment.
Half-life of a reaction.
The time taken for the concentration of a reactant to fall to half its original value.
Halogen carrier
A catalyst that helps introduce a halogen atom into the benzene ring.
Hazard
Property of a substance that could cause harm to the user.
High resolution mass spectrometry
Type of mass spectrometry that can produce Mr values with several decimal places, usually four or more.
Homogeneous catalyst
One that is in the same phase as the reactants.
Hydrolysis
The breaking of a compound by water into two compounds.
Instantaneous reaction rate
The gradient of a tangent drawn to the line of the graph of the concentration against time. The instantaneous rate varies as the reaction proceeds (except for a zero-order reaction).
Integration trace
Shows the relative numbers of equivalent protons (i.e. in the same chemical environment).
Isoelectric point of an amino acid
The pH of an aqueous solution in which it is neutral.
Kw
[H+(aq)][OH-(aq)]
Ligand
Species that uses a lone pair of electrons to form a dative bond with the metal ion.
Mobile phase
The liquid that moves through the stationary phase and transports the components.
Monodentate ligand
One that forms one dative bond with a metal ion.
Multidentate ligand
One that forms several dative bonds with a metal ion.
Multiplets
The different splitting patterns observed (singlets, doublets, triplets or quartets).
Nuclear magnetic resonance spectroscopy
Technique used to find the structures of organic compounds. It depends on the ability of nuclei to resonate in a magnetic field.
Nucleophilic addition
Type of mechanism in which a molecule containing two atoms or groups is added across a polar double bond (usually C=O), and the attacking species in the first step is a nucleophile.
Optical activity
Shown by a substance, if it rotates a plane of plane-polarised light.
Order of a reactant species
The power to which the concentration of the species is raised in the rate equation.
Overall order
The sum of all the individual orders.
Partial pressure of a gas in a mixture of gases
The pressure that a gas would exert, if it alone occupied the volume of the mixture.
Peak in a 1H NMR spectrum
Shows the presence of hydrogen atoms (protons) in a specific chemical environment.
Peptide bond
The bond formed by a condensation reaction between the carbonyl group of one amino acid and the amine group of another amino acid.
pH of an aqueous solution
The reciprocal of the logarithm to the base 10 of the hydrogen ion concentration measured in moles per cubic decimetre. pH = -lg [H+].
pKa =
-lg Ka
Plane-polarised light
Monochromatic light that has oscillations only in one plane.
Polarimeter
The apparatus used to measure the angle of rotation caused by a substance.
Polariser
A material that converts unpolarised light into plane-polarised light.
Base
Proton acceptor
Acid
Proton donor
Racemic mixture
Equimolar mixture of two enantiomers that has no optical activity.
Rate-determining step
The slowest step in the mechanism for a reaction.
Rate equation
An equation expressing the mathematical relationship between the rate of reaction and the concentration of reactants.
Overall rate equation
The change in the concentration of a species divided by the time it takes for the change to occur. All reaction rates are positive.
Risk
Possible effect that a substance may cause to a user, and this depends on factors such as concentration and apparatus. Control measures control the level of risk.
Six-fold coordination
Complexes in which there are six ligands forming coordinate bonds with the transition metal ion.
Splitting pattern
The appearance of a peak as a small number of small sub-peaks very close to each other.
Spontaneous process
Takes place without continuous intervention.
Square planar
A shape that contains a central atom or ion surrounded by 4 atoms or ligands in the same plane with bond angles of 90 degrees.
Standard enthalpy change of atomisation
The enthalpy change measured at a stated temperature, usually 298K, and 100kPa, when one mole of gaseous atoms is formed from an element in its standard state.
Stationary phase in paper chromatography
The liquid or solid that does not move.
Transition metal
An element that forms one or mole stable ions with incompletely filled d-orbitals.
Unimolecular
A mechanism in which one species is reacting in the rate-determine step.
Unpolarised light
Oscillations in all planes at right angles to the direction of travel.
Zwitterion
A molecule containing positive and negative charges, but with no overall charge.
