Definitions Flashcards
First Ionisation Energy
Energy required to remove one electron from each atom in a mole of gaseous atoms to form one mole of gaseous ions
Relative atomic mass
The weighted mean mass of an atom of an element compared with one-twelfth of the mass of an atom of carbon-12
Relative molecular mass
Relative molecular mass
The weighted mean mass of a molecule compared with one-twelfth of the mass of an atom of carbon-12
Empirical formula
The simplest whole number ratio of atoms of each element present in a compound
Dative covalent bond
A covalent bond where both electrons in the shared pair come from the same atom
Eletcronegativity
The power of an atom to attract negative charge towards itself in a covalent bond
Enthalpy change
Heat energy change measured at constant pressure (ΔH)
Standard Enthalpy of Formation
The change in Enthalpy that accompanies the formation of 1 mole of a compound from its elements with all substances in their standard states
Standard Enthalpy of Combustion
The enthalpy change when one mole of a substance is completely burnt in oxygen under standard conditions
Mean Bond Enthalpy
The average enthalpy change when breaking a certain type of bond, averaged over a range of compounds
Specific Heat Capacity
The energy required to raise the temperature of one gram of a substance by one degree Celsius
Hess’s Law
The enthalpy change of a reaction is independent of the route taken
Activation Energy
The minimum amount of kinetic energy that particles need in order to react
Reaction Rate
The change in concentration of a reactant or product per unit time
Catalyst
A substance that increases the rate of reaction without being used up in the reaction. It does this by offering an alternative path with a lower activation energy
Dynamic Equilibrium
Equlibrium where the froward and backwards reactions occur at the same rate. In a closed system
Le Chatelier’s Principle
If a reaction at equilibrium is subjected to a change in concentration, pressure or temperature, the position of equilibrium will move to counteract the change
Compromised Conditions
Conditions that take into consideration max. yield and rate of reaction
Oxidation
Loss of electrons
Reduction
Gain of electrons
Oxidation State
No. of electrons accepted or donated
Oxidising Agent
Electron acceptor and gets reduced
Reducing Agent
Electron donor and gets oxidised
Lattice energy of dissociation
The enthalpy change when 1 mole of a solid ionic compound is completely dissociated into its gaseous ions under standard conditions
Lattice formation of enthalpy
The enthalpy change when 1 mole of a solid ionic
compound is formed from its constituent gaseous ions under standard conditions
Atomisation enthalpy
The enthalpy change when one mole of gaseous atoms is formed from its constituent element under standard conditions
Enthalpy of electron affinity
The enthalpy change when one mole of electrons is added to a mole of gaseous atoms under standard conditions
Enthalpy of solution
The enthalpy change when one mole of an ionic solid dissolves in an infinite amount of water so that the dissolved ions are separated and do not interact with each other, under standard conditions
Enthalpy of hydration
The enthalpy change when one mole of gaseous ions is dissolved in an infinite amount of water to form to one mole of aqueous ions under standard conditions
Entropy
Measure of disorder
Free Energy Change ΔG?
A measure used to predict wether a reaction is feasible
Overall Order of Reaction
The sum of the powers to which the concentration terms are raised in the rate equation
Standard Electrode Potential
The voltage measured under standard conditions when a half cell is connected to a standard hydrogen electrode
Electrochemical Series
A list of electrode potentials in numerical order
Bronsted Lowry acid
proton donor
Bronsted Lowry base?
proton acceptor
pH
measure of hydrogen ion concentration
Buffer
A solution that resists change in pH when small volumes of acid or base are added
Disproportionation reaction
When something is both reduced and oxidised
Amphoteric
Can act as an acid or a base
Transition metal
Elements in the d block of the periodic table with a partially filled d orbital
Complex
Central metal atom or ion surrounded by co-ordinately bonded ligands
Ligand
atom/ion/molecule that donates a pair of electrons to a central transition metal ion to form a co ordinate bond
Chelate Effect
Positive entropy change is favourable so monodenatate lingands are substituted with bidentate and multidentate ligands (more moles on RHS)
eg [Fe (H2O)6]3+ + EDTA 4- –> [Fe (EDTA)]- +6H2O) more moles formed so favourable
Heterogeneous catalyst
A catalyst that is in a different phase or state to the species in the reaction
Homogenous catalyst
A catalyst that is in the same phase/state as the species in the reaction
Homologou series
Series of organic compounds which contain the same functional group
Stereoisomerism
Same molecular formula but different spatial arrangement
Biofuel
Fuel that’s made from biological material that’s recently died
Esterification
Making esters by reacting carboxylic acids and alcohols
Saponification
Alkaline hydrolisis of fats into glycerol and the salts of the fatty acids present in the fat
Trans-esterification
Reacting an ester with an alcohol to produce a different ester and a different alcohol (eg production of biodiesel)
Acid derivatives
Compounds that are related to carboxylic acids, the OH group has been replaced by something else
Acylation
The process in which an acyl group is added to a molecule
Arene
An aromatic compound - contains a benzene ring as part of its structure
Nitration
When you warm benzene with conc. nitric and sulfuric acid and get nitrobenzene
Inductive effect
An electron pushing effect - alters the electron density distribution in a molecule
Amphoteric
Has both acidic and basic properties
Zwitterion
Dipolar ion that has both positive and negative charge in different parts of the molecule
Isoelectric point
pH where average overall charge is zero
Proteins
Sequences of amino acids joined by peptide bonds
Enzymes
Proteins that act as biological catalysts
Inhibitor
Slows down rate of reaction (bonds to active site ∴ blocking it)
DNA
Polymer of nucleotides
