Module 3 - Keywords Flashcards
Periodicity
Repeating trends in physical and chemical properties across periods
s block element
An element with its highest energy electron in an s orbital
p block element
An element with its highest energy electron in a p orbital
d block element
An element with its highest energy electron in a d orbital
First ionisation energy
Energy required to remove 1 mole of electrons from 1 mole of gaseous atoms to form 1 mole of gaseous 1+ ions
Second ionisation energy
Energy required to remove 1 mole of electrons from 1 mole of gaseous 1+ ions to form 1 mole of gaseous ions
Successive ionisation energies
Energy required to remove each subsequent 1 mole of electrons from 1 mole of gaseous ions
Nuclear charge
The positive charge found on the nucleus of every atom
Metallic bonding
Strong electrostatic attraction between cations (positive ions) and delocalised electrons
Giant covalent lattices
Networks of atoms bonded by strong covalent bonds
Diatomic
Molecule containing 2 atoms
Disproportionation
Oxidation and reduction of the same element
Bleach
Formed by the reaction of chlorine with cold, dilute aqueous sodium hydroxide
Precipitate
A solid that forms on reaction of solutions
Halide
A compound containing an element from group 17 (halogens)
Exothermic
Reaction which releases energy. ΔH is negative. Bond making
Endothermic
Reaction which takes in energy. ΔH is positive. Bond breaking
Activation energy
The minimum energy which must be available to a chemical system with potential reactants to result in a chemical reaction
Standard conditions
100kPa, 298K, substances in their standard states
Enthalpy change of reaction, ΔrH
Enthalpy change associated with a stated equation
Enthalpy change of formation, ΔfH
Enthalpy change associated with the formation of 1 mole of a compound from its elements
Enthalpy change of combustion, ΔcH
The enthalpy change associated with the complete combustion of 1 mole of a compound
Enthalpy change of neutralisation, ΔnH
The enthalpy change associated with the formation of 1 mole of water in a neutralisation reaction
Average bond enthalpy
A measurement of covalent bond strength. It’s the energy change associated with breaking 1 mole of bonds in gaseous molecules
Hess’s law
The total energy change for a reaction is the same regardless of the route taken
Concentration
A measure of the number of a type of particle in a certain volume (gdm-3 or moldm-3)
Simple collision theory
In order to react, particles need to collide and have the activation energy needed to react
Rate of reaction
The change in concentration of a reactant or a product with time
Catalyst
A chemical that provides a new route for the reaction with a lower activation energy. It is not used up in a chemical reaction.
Homogeneous
A catalyst in the same phase as the reagents
Heterogeneous catalyst
A catalyst in a different phase to the reagents
Boltzmann distribution
A graph that shows the probability distribution of particles with different energies
Dynamic equilibrium
An equilibrium where the rate of the forward reaction is equal to the rate of the reverse reaction
Closed system
A reaction where nothing can enter or leave the container
Equilibrium constant, Kc
A measure of the position of a dynamic equilibrium which relates the concentrations of the reactants and products
