Keywords 1 Flashcards
Accuracy
Measure of how close values are to the corrected/accepted value.
Activation Energy
Ea, the minimum energy that colliding particles must possess for a reaction to occur.
Actual yield
The actual mass obtained in a reaction.
Addition reaction
Two molecules combine to form one molecule.
Aldehydes
A homologous series of organic compounds formed by the partial oxidation of primary alcohols.
Atom economy
Molar mass of the desired product divided by the sum of the molar masses of all the products, expressed as a percentage.
Atomic Number (z)
The number of protons in the nucleus of an atom of an element.
Avogadro’s constant
The number of atoms of carbon 12 in exactly 12g of carbon 12.
Avogadro’s Law
Equal volumes of gases under the same conditions of temperature and pressure contain the same numbers of molecules.
Base peak
Peak with the greatest abundance.
Basic oxides
Oxides of metals that react with water to form metal hydroxides, and with acids to form salts and water.
Bioalcohols
Fuels made from plant matter, typically using enzymes or bacteria.
Biodegradable polymers
Can be broken down by microbes.
Biodiesel
Fuel made from vegetable oils obtained from plants.
Biofuels
Fuels obtained from living matter that has died recently.
Bond enthalpy
The enthalpy change when one mole of the bond in the gaseous state is broken.
Bond length
The distance between the nuclei of the two atoms that are covalently bonded together.
Carbocation
A positive ion in which the charge is shown on the carbon atom.
Carboxylic acids
A homologous series of organic compounds formed by the complete oxidation of primary alcohols.
Catalyst
Substance that increases the rate of a chemical reaction, but is chemically unchanged at the end of the reaction.
Coefficients
Numbers written in front of species when balancing an equation.
Complete Combustion
All of the atoms in the fuel are fully oxidised.
Concordant titres
Those that are close together, usually within 0.20 cm3 of each other.
Cracking
The breakdown of molecules into shorter ones by heating with a catalyst.
Curly arrows
Represent the movement of electron pairs.
Dehydration reaction
Results in the removal of the hydroxyl group in an alcohol molecule, together with a hydrogen atom from an adjacent carbon atom, forming a C=C double bond.
Delocalised electrons
Electrons not associated with any single atom or any single covalent bond.
Diol
A compound containing two OH groups.
Dipole
Said to exist when two charges of equal magnitude but opposite signs are separated by a small distance.
Discrete simple molecule
An electrically neutral group of two or more atoms held together by covalent bonds.
Displacement reaction
A reaction in which one element replaces another element in a compound.
Displayed formula
Shows every atom and every bond.
Disproportionation
The simultaneous oxidation and reduction of an element in a single reaction.
Distillation with addition
Involves heating a reaction mixture, but adding another liquid and distilling off the product as it forms.
Electronegativity
The ability of an atom to attract a bonding pair of electrons in a covalent bond.
Electronic configuration
Shows the number of electrons in each sublevel in each energy level of an atom.
Electron-releasing
A group that pushes electrons towards the atom to which it is joined.
Electrophile
A species that is attracted to a region of high electron density.
Electrophilic addition
A reaction in which two molecules form one molecule and the attacking molecule is an electrophile.
Elimination
Reaction in which a molecule loses atoms attached to the adjacent carbon atoms forming a C=C double bond.
Empirical formula
Shows the numbers of each atom in the simplest whole-number ratio.
End point
Point at which the indicator just changes colour. Ideally, the end point should coincide with the equivalence point.
Endothermic
Heat energy is transferred from the surroundings to the system.
Equivalence point
Point at which there are exactly the right amounts of substances to complete the reaction.
Error
The difference between an experimental value and the accepted/correct value.
Ethanolic solution
One in which ethanol is the solvent.
Feedstock
Converting polymer waste into feedstock that can be used to make new polymers.
First ionisation energy
The energy required to remove an electron from each atom in one mole of atoms in a gaseous state.
Fractional distillation
Process used to separate a liquid mixture into fractions by heating and condensing.
Fragmentation
Occurs when the molecular ion breaks into smaller pieces.
Functional group
An atom or group of atoms in a molecule that is responsible for its chemical reactions.
Geometric isomers
Compounds containing a C=C bond with atoms or groups attached at different positions.
Halogenation
Involves the addition of a halogen.
Heating under reflux
Heating a reaction mixture with a condenser fitted vertically.
Hess’s Law
The enthalpy change of a reaction is independent of the path taken in converting reactants into products, provided the initial and final conditions are the same in each case.
Heterogeneous catalyst
One in a different phase to that of the reactants.
Heterogeneous system
Where at least two different systems are present.
Heterolytic fission
The breaking of a covalent bond, so that both bonding electrons are taken by one atom.
Homogeneous system
System in which all components are in the same phase.
Homologous series
A family of compounds with the same functional group, which differ in formula by CH2 from the next member.
Homolytic fission
The breaking of a covalent bond where each of the bonding electrons leaves with one species, forming radicals.
Hund’s Rule
Electrons will occupy orbitals singly before pairing takes place.
Hydrates
Compounds containing water of crystallisation, indicated in the formulae by .H2O .
Hydration
Involves the addition of water or steam.
Hydrocarbon
A compound that contains ONLY carbon and hydrogen atoms.
Hydrogen bond
Intermolecular interaction between a hydrogen atom of a molecule (or molecular fragment) bonded to another atom which is more electronegative than hydrogen and another atom in the same or a different molecule.
Hydrogenation
Involves that addition of hydrogen.
Hydrolysis
Reaction in which water or hydroxide ions replace an atom in a molecule with an —OH group.
Incinerator
Converts polymer waste into energy.
Incomplete combustion
Some of the atoms in the fuel are not fully oxidised.
Infrared radiation
Part of the EM spectrum with frequencies below that of red light.
Initiation step
Involves the formation of free radicals, usually as a result of bond breaking caused by UV radiation.
Intensity of an infrared absorption
The amount of infrared radiation absorbed.
Isotopes
Atoms of the same element with different masses.
Ketones
A homologous series of organic compounds formed by the oxidation of secondary alcohols.
Locant
Number used to indicate which carbon atom in the chain an atom or group is attached to.
Mass concentration of a solution
Mass in grams of the solute divided by the volume of the solution.
Mass number
The sum of the number of protons and the number of neutrons in the nucleus of an atom.
Mean bond enthalpy
Enthalpy change when one mole of a bond, averaged out over many different molecules, is broken.
Measurement uncertainty
The potential error involved when using a piece of apparatus to take a measurement.
Mechanism
The sequence of steps in an overall reaction. Each step shows what happens to the electrons involved in bond breaking or bond formation.
Meniscus
The curving of the upper surface in a liquid in a container. The lowest, horizontal part of the meniscus should be read.
Metallic bonding
Electrostatic force of attraction between the nuclei of metal cations and the delocalised electrons.
Molar concentration of a solution
The amount in moles of a solute divided by the volume of the solution.
Molar mass
The mass per mole of a substance. Symbol: M. Units: gmol -1.
Molar volume
Volume occupied by 1 mole of any gas.
Mole
The amount of a substance that contains the same number of particles as the number of carbon atoms in exactly 12g of the carbon-12 isotope.
Molecular formula
Shows the actual number of atoms of each element in a molecule.
Molecular ion peak
Peak with the highest m/z ratio in the mass spectrum, the M peak.
Monomers
Small molecules that combine together to form a polymer.
Multiple bond
Two or more covalent bonds between two atoms.
Nitriles
Organic compounds containing the C—CN group.
Non-renewables
Energy sources not being replenished, except over geological timescales.
Nucleophile
Species that donates a lone pair of electrons to form a covalent bond with an electron-deficient atom.
Nucleophilic substitution
Reaction wherein an attacking nucleophile replaces an existing atom or group in a molecule.
Orbital
Region within an atom that can hold up to 2 electrons with opposite spins.
Oxidation
Loss of electrons.
Oxidation number
Charge that an ion has or that a species would have, if it were ionic.
Oxidised
An element is oxidised when its oxidation number increases.
Oxidising agent
Species that oxidises another species by removing one or more electrons. When an oxidising agent reacts, it gains electrons, so is reduced.
Pauli Exclusion Principle
Two electrons cannot occupy the same orbital unless they have opposite spins. Spin is shown by up and down arrows.
% uncertainty
The actual measurement uncertainty x 100 and divided by the value recorded.
% yield
100 x the actual yield divided by the theoretical yield.
Periodicity
Regularly repeating pattern of chemical, physical and atomic properties with increasing atomic number.
Pi bonds
Covalent bonds formed when electron orbitals overlap sideways.
Polar covalent bond
Type of covalent bond between two atoms where the bonding electrons are unequally distributed. One atom carries a partial positive charge and the other a partial negative charge.
Precipitation reaction
An insoluble solid is one of the products.
Precision
A measure of how close values are to each other.
Primary amines
Compounds containing the C—NH2 group.
Primary standards
Substances used to make a standard solution by weighing.
Propagation
Two steps that, when repeated many times, convert the starting materials into the products of the reaction.
Quantum shell
The energy level of an electron.
Radical
Species that contains an unpaired electron.
Random errors
Errors caused by unpredictable variations in conditions.
Recycling
Converting polymer waste into other materials.
Redox reaction
A reaction; that involves both reduction and oxidation.
When an element is reduced…
Its oxidation number decreases.
Reducing agent
Species that reduces another species by adding one or more electrons. When a reducing agent reacts, it loses electrons, so is oxidised.
Reduction
Gain of electrons.
Reforming
The conversion of straight-chain hydrocarbons into branched-chain and cyclic hydrocarbons.
Relative atomic mass (Ar)
The weighted mean of a mass of an atom of an element compared to 1/12 the mass of an atom of carbon 12.
Relative isotopic mass
The mass of an individual atom of a particular isotope relative to 1/12 the mass of an atom of carbon-12.
Renewable
Energy sources that can be continuously replaced.
Repeat unit
The set of atoms that are joined together in large numbers to produce the polymer structure.
Restricted rotation…
Around a C=C double bond fixes the position of the atom or groups of atoms attached to the C=C atoms.
Saturated
A compound containing only single bonds.
Second ionisation energy
The energy required to remove an electron from each singly-charged, positive ion in one mole of positive ions in the gaseous state.
Sigma bonds
Covalent bonds formed when electron orbital overlap axially/end on.
Simple distillation
Used to separate liquids with very different boiling temperatures.
Skeletal formula
Shows all the bonds between carbon atoms.
Solute
A substance that is dissolved.
Solution
Solute dissolved in a solvent.
Solvent
Substance that dissolves a solute.
Solvent extraction
Used to separate a liquid from a mixture by causing it to move from the mixture to the solvent.
Spectator ions
Ions in an ionic compound that do not take part in a reaction.
Standard enthalpy change of combustion
The enthalpy change measured at 100kPa and a stated temperature, usually 298K, when one mole of a substance is completely burnt in oxygen.
Standard enthalpy of formation
The enthalpy change measured at 100kPa and a specified temperature, usually 298K, when one mole of a substance is formed from its elements in their standard states.
Standard enthalpy change of neutralisation
The enthalpy change measured at 100kPa and a stated temperature, usually 298K, when one mole of water is produced by the neutralisation of an acid with an alkali.
Standard enthalpy change of a reaction
The enthalpy change measured at 100kPa and a stated temperature, usually 298K, when the number of moles of substances in the equation as written react.
Standard solution
A solution whose concentration is accurately known.
Stereoisomers
Compounds with the same structural formula, but with atoms or groups arranged differently in 3D.
Stretching
Occurs when a bond absorbs infrared radiation and uses it to alter the length of the bond.
Structural formula
Shows how the atoms are joined together.
Structural isomers
Compounds with the same molecular formula, but with different structural formulae.
Substitution reaction
One in which an atom or group is replaced by another atom or group.
Systematic errors
Errors that are constant or predictable, usually because of the apparatus used.
Termination step
Involves the formation of a molecule from two radicals.
Theoretical yield
The maximum possible mass of a product, assuming complete reaction and no losses.
Thermal stability
A measure of the extent to which a compound decomposes when heated.
Titre
The volume added from a burette during a titration.
Transmittance
Value in an infrared spectrum that represents the amount of radiation absorbed at a particular wavelength.
Unsaturated
A compound containing one or more multiple bonds.
Wave number of an infrared absorption
Represents the frequency of infrared radiation absorbed by a particular bond in a molecule.
