ALL DEFINITIONS EVER Flashcards
Concentration
The amount of solute in moles dissolved in 1dm3 of solution
Amount of substance
The quantity whose unit is the mole. Chemists use amount of substance as a means of counting atoms
Mole
The number of atoms of Carbon-12 in 12g of Carbon-12
Avogrado Constant
6.02x10(23) - number of atoms per 1 mole of Carbon-12
Molar Mass
The mass per mol of a substance. Unit is g/mol
Empirical formula
The simplest whole number ratio of atoms of each element in a compound
Molecular formula
The actual number of atoms of each element in a molecule
Anhydrous
Crystals that have no water molecules in their crystalline structure
Hydrated
Crystals that have water molecules as part of their crystalline structure
Water of Crystallisation
The water molecules part of a crystalline structure
Solute
A material that is dissolved
Solvent
A material that does the dissolving
Solution
The mixture made from dissolving a solute in a solvent
Standard solution
A solution with a known concentration
Concentrated
A large number of moles of solute per dm3 of solution
Dilute
A small number of moles of solute per dm3 of solution
Ideal gas
A hypothetical gas that obeys the gas laws exactly
Ionic bonding
The electrostatic attraction between positive and negative ions
Covalent bond
The strong electrostatic attraction between a shared pair of electrons and the nuclei of the bonded atoms
Lone pair
A pair of electrons in the outer shell not used in bonding
Dative covalent bond
A shared pair of electrons in which the bonded pair has been provided by one of the bonding atoms only
Average bond enthalpy
The average enthalpy change which takes place when breaking bonds by homolytic fission 1 mol of a given type of bond in the molecules of a gaseous species
Metallic bonding
The electrostatic attraction between positive metal ions and delocalised electrons
Malleable
Easily bent into different shapes
Ductile
Can be drawn into a wire without breaking
Alloys
Mixtures of metals
Electronegativity
The ability of an atom to attract the bonding electrons in a covalent bond
Polar covalent bond
A bond with a permanent dipole, having positive and negative partial charges of the bonded atoms
Polar molecule
A molecule with an overall dipole, having taken into account any dipoles across bonds and the shape of the molecule
Hydrogen bond
A strong dipole-dipole attraction between an electron deficient hydrogen atom of NH, OH or HF on one molecule and a lone pair of electrons on a highly electronegative atom (N, O, F) on a different molecule
Group on the periodic table
Vertical column - same number of electrons on outer shell and similar chemical properties
Period on the periodic table
Horizontal row - elements show trends in properties across the table
Periodicity
The regular repeating pattern in properties of the elements across different periods
First Ionisation energy
The amount of energy required to remove 1 electron from each atom in a mole of gaseous atoms of an element to form 1 mole of gaseous 1+ ions
Reducing agent
Something that donates electrons to something else, enabling reduction to occur. In this process it is oxidised
Oxidising agent
Something that accepts electrons from something else, enabling oxidation to occur. In this process it is reduced
Solubility
A measure of the ability of a solute to dissolve in a solvent
Alkali
A base that releases OH- ions in solution
Alkaline
A term used to describe a solution containing hydroxide ions
Alkalinity
A measure of the concentration of hydroxide ions present in an alkaline solution
pH
A measure of the concentration of hydrogen ions present in a solution
Disproportionation
A reaction where the same element is both oxidised and reduced
Enthalpy
The measure of the heat energy in a chemical system
System (in terms of enthalpy)
The reactants and products
Surroundings (in terms of enthalpy)
The rest of the universe
Exothermic
Energy is transferred from the system to the surroundings
Endothermic
Energy is transferred from the surroundings to the system
Activation energy
The minimum energy required to start a reaction by the breaking of bonds
Standard enthalpy change of combustion
The enthalpy change when 1 mole of substance reacts completely with excess oxygen under standard conditions with all products and reactants in their standard states
Standard enthalpy change of formation
The enthalpy change when 1 mole of a compound is formed from its elements in their standard states under standard conditions
Standard enthalpy change of neutralisation
The enthalpy change when the reaction of an acid and a base reacts to form 1 mole of water under standard conditions with all reactants and products in their standard states
Hess’s Law
If a reaction can take place by more than 1 route and the initial and final conditions are the same, the total enthalpy change is the same for each route
Hydrocarbon
A molecule containing only carbon and hydrogen
Aliphatic
A compound containing carbon and hydrogen joined together in straight chains, branched chains or non-aromatic rings
Alicyclic
An aliphatic compound arranged in non-aromatic rings with or without side chains
Aromatic
A compound containing a benzene ring
Saturated
Single carbon-carbon bonds only
Unsaturated
The presence of multiple carbon-carbon bonds
Homologous series
A series of organic compounds having the same functional group and each successive member differing by CH2
Functional group
A group of atoms responsible for the characteristic reactions of a compound
Skeletal formula
The simplified organic formula, shown by removing H atoms from alkyl chains, leaving just a carbon skeleton and associated functional groups
Displayed formula
The relative positioning of atoms and the bonds between them
General formula
The simplest algebraic formula of a member of a homologous series
Structural formula
The minimal detail that shows the arrangement of atoms in a molecule
Structural isomers
Compounds with the same molecular formula but different structural formula
Homolytic fission
When a covalent bond breaks each bonding atom receives 1 electron, forming 2 radicals
Heterolytic fission
When a covalent bond breaks 1 bonding atom receives both electrons, forming 1 anion and 1 cation
Radical
A species with an unpaired electron
Pi-bond
A bond formed by the sideways overlap of 2 p-orbitals with the electron density above and below the plane of the atom
Electrophile
An electron acceptor
Carbocation
A compound that contains a positively charged carbon atom
Markownikoff’s rule
When a hydrogen halide is added to an unsymmetrical alkene, the most likely product is the one in which the H atom adds to the carbon that already has the most H’s attached to it
Atom economy
A measure of how well the atoms were utilised
% yield
Shows us the percentage of how much product was made compared to how much should’ve been made
Hydrolysis
A chemical reaction involving water or an aqueous solution of a hydroxide that causes the breaking of a bond in a molecule
Reflux
The continuous evaporation and condensation of a reaction solution back into the original container to ensure the reaction takes place without the contents boiling dry
Nucleophile
An electron pair donor
Elimination
The removal of a molecule from a saturated molecule to make an unsaturated molecule
Greenhouse effect
Warming of the atmosphere due to the trapping of IR by absorption by molecular bonds
Lattice enthalpy
The enthalpy change when 1 mole of an ionic compound is formed from its ions in the gaseous state under standard conditions
First ionisation enthalpy
The enthalpy change when 1 electron from each atom in 1 mole of atoms of an element are removed, forming 1 mole of gaseous 1+ ions
Standard enthalpy of atomisation
The enthalpy change when 1 mole of gaseous atoms are formed from the element in its standard state under standard conditions
Standard enthalpy of solution
The enthalpy change when 1 mole of a compound is completely dissolved in water under standard conditions
Entropy
An energy value generally described as disorder. It is related to temperature and quantity
Electron affinity enthalpy
The enthalpy change when 1 electron is added to each atom in 1 mole of gaseous atoms of an element
Acid
Proton donor
Base
Proton acceptor
Weak acid
An acid that is only partially dissociated in solution
Strong acid
Fully dissociated in solution
Salt
Ionic compounds formed when the H+ ions in an acid are replaced by metal or ammonium ions
Spectator ions
Ions that remain unchanged at after a reaction
Redox reaction
A reaction where both oxidation and reduction has happened
Precipitate
The solid formed from a solution during a chemical reaction. Often formed when 2 aqueous solutions are mixed together
Ionic equation
The balanced symbol equation but with any spectator ions removed
Atomic number
The number of protons in the nucleus of the atom of an element
Isotopes
Atoms that have the same number of protons but different number of neutrons
Mass number
The number of protons plus the number of neutrons
Relative isotopic mass
The mass of 1 atom of an isotope compared to 1/12 the mass of 1 atom of Carbon-12
Relative atomic mass
The weighted mean mass of 1 atom of an element compared to 1/12 the mass of 1 atom of Carbon-12
Relative molecular mass
The weighted mean mass of a molecule compared to 1/12 the mass of 1 atom of Carbon-12
Relative formula mass
The weighted mean mass of a formula unit compared to 1/12 the mass of 1 atom of Carbon-12
Reduction
Gain of electrons
Oxidation
Loss of electrons
Addition polymerisation
Formation of a very long molecular chain, by repeated addition reactions of many unsaturated alkene molecules (monomers)
Alkyl group
A side chain formed by removing a hydrogen atom removed from an alkane parent chain
Orbital
A region around the nucleus that can hold up to two electrons, with opposite spins
Fingerprint region
An area of an infrared spectrum below 1500 that gives a characteristic pattern for different compounds
Fragment ions
Ions formed from the breakdown of the molecular ions in a mass spectrometer
Fragmentation
The process in mass spectrometry that causes a positive ion to split into smaller pieces, one of which is a positive fragment ion
Intermolecular force
Attractive force between molecules. Intermolecular forces can be London forces, permanent dipole-dipole interactions or hydrogen bonding
Molecular ion
The positive ion formed in mass spectrometry when a molecule loses an electron
Nucleophilic substitution
A reaction in which a nucleophile is attracted to an electron deficient carbon atom, and replaces an atom or group of atoms on the carbon atom
Sigma bond
A bond formed by the overlap of one orbital from each bonding atom, consisting of two electrons and with the electron density centred around a line directly between the nuclei of the two atoms
Shell
A group of orbitals with the same principal quantum number
Standard enthalpy change of hydration
The enthalpy change when 1 mole of isolated gaseous ions is dissolved in water, forming 1 mole of aqueous ions under standard conditions
Standard enthalpy change of reaction
The enthalpy change that accompanies a reaction in the molar quantities expressed in a chemical equation under standard conditions, all reactants and products in their standard states
Stereoisomers
Compounds with the same structural formula but with different arrangement of the atoms in the space
Sub-shell
A group of the same type of orbitals within a shell
Volatility
The ease at which a liquid turns into a gas. Increases as boiling point decreases
