key definitions Flashcards
Terms from specification must learn (42 cards)
EL Fusion reaction
lighter nuclei join to heavier nuclei under conditions of high temperature and pressure
EL ionisation enthalpy
the amount of energy required to remove mole of e- from one mole of gaseous atoms
EL charge density
a measure of the concentration of charge on a cation (the smaller the 2+ ion the higher the charge density)
EL acid
the ability to transfer H+ ions to something else (proton donor)
EL base
substance that accepts the H+ (proton acceptor)
EL alkali
soluble base substance.
EL neutralisation
chemical reaction between an acid and a base to form a salt and water. The reaction results in a neutral solution, meaning that the concentration of hydrogen ions (H+) and hydroxide ions (OH-) is equal, leading to a pH of 7.
DF exothermic
bonds formed [MAKING] are stronger than bonds broken
DF endothermic
bonds formed are weaker than bonds broken [BREAKING]
DF enthalpy change of reaction
Enthalpy change of reaction is the heat change accompanying a chemical reaction at constant volume or constant pressure. It represents the amount of heat absorbed or evolved during the reaction and is denoted by ΔH.
DF enthalpy change of formation
one mole of a compound is formed from its constituent elements in their standard state
DF enthalpy change of combustion
for one mole of a substance reacting completely with oxygen under standard conditions ( 1 atm and 298k)
DF enthalpy change of neutralisation
when one mole of hydrogen ions react with one mole of hydroxide ions to form one mole of water under standard conditions
DF average bond enthalpy
the energy required to break a particular COVALENT bond in one mole of a molecule in the GASEOUS state.
DF catalyst
a substance which speeds up the rate of reaction but can be recovered chemically unchanged at the end, by providing an alternative pathway
DF Catalysis
the process of speeding up a chemical reaction by using a catalyst
DF catalyst poison
a substance that stops catalyst functioning properly
DF heterogenous catalyst
catalyst and reactants in different physical states
DF homogenous catalysts
catalysts and reactants are in the same physical state
DF cracking
the breakdown of long chained saturated hydrocarbons to form a mixture of shorter chained alkanes and alkenes
DF radical
atoms of molecules which have an unpaired e-
DF aliphatic
hydrocarbons with a carbon atom joined together by straight/ branched chains WITHOUT containing benzene rings
DF aromatic
compound that contains one or more benzene rings
DF arene
