AQA A level Chemistry 3.1.8 –
Thermodynamics with verified
questions and answers
What are standard conditions? - correct answer.💖💖💖💖✔<<<<<298K/25°C
100kPa/1 atm
1 moldm-3
Enthalpy change of formation - correct answer.💖💖💖💖✔<<<<<The enthalpy change when 1
mole of a compound is formed from its constituent elements under standard conditions, with all
reactants and products in their standard states.
Enthalpy change of combustion - correct answer.💖💖💖💖✔<<<<<The enthalpy change when 1
mole of a substance is burned completely in oxygen.
Enthalpy change of atomisation - correct answer.💖💖💖💖✔<<<<<The enthalpy change that
accompanies the formation of 1 mole of gaseous atoms from the element in its standard state.
First ionisation enthalpy - correct answer.💖💖💖💖✔<<<<<The enthalpy change when 1 mole of
gaseous atoms loses 1 electron per atom to form 1 mole of gaseous 1+ ions.
Second ionisation enthalpy - correct answer.💖💖💖💖✔<<<<<The enthalpy change when 1 mole
of gaseous 1+ ions loses 1 electron per atom to form 1 mole of gaseous 2+ ions.
First electron affinity - correct answer.💖💖💖💖✔<<<<<The enthalpy change when 1 mole
gaseous atoms gains 1 electron per atom to form 1 mole of gaseous 1- ions.
Second electron affinity - correct answer.💖💖💖💖✔<<<<<The enthalpy change when 1 mole of
gaseous 1- ions gains 1 electron per atom to form 1 mole of gaseous 2- ions.
, Mean bond enthalpy - correct answer.💖💖💖💖✔<<<<<The enthalpy change when 1 mole of
gaseous molecules each breaks a covalent bond to form 2 gaseous ions or free radicals.
Lattice enthalpy of formation - correct answer.💖💖💖💖✔<<<<<The enthalpy change when 1 mole
of a solid ionic compound is formed from its gaseous ions.
Lattice enthalpy of dissociation - correct answer.💖💖💖💖✔<<<<<The enthalpy change when 1
mole of a solid ionic compound dissociates into its gaseous ions.
Enthalpy of hydration - correct answer.💖💖💖💖✔<<<<<The enthalpy change when 1 mole of
gaseous ions dissolves completely in water.
Enthalpy of solution - correct answer.💖💖💖💖✔<<<<<The enthalpy change when 1 mole of an
ionic solid dissolves in enough solvent to ensure that the dissolved ions are well separated and do not
interact with one another.
Enthalpy of vaporisation - correct answer.💖💖💖💖✔<<<<<The enthalpy change when 1 mole of a
liquid evaporates to form 1 mole of a gas.
Enthalpy of sublimation - correct answer.💖💖💖💖✔<<<<<The enthalpy change when 1 mole of a
solid sublimes to form 1 mole of a gas.
Why are ionisation enthalpies always positive (endothermic)? - correct
answer.💖💖💖💖✔<<<<<Energy needs to be put in to pull an electron away from the nucleus to
overcome the electrostatic attraction.
Why are first electron affinities always negative (exothermic)? - correct
answer.💖💖💖💖✔<<<<<Energy is given out when an electron is attracted to the positively
charged nucleus.
Thermodynamics with verified
questions and answers
What are standard conditions? - correct answer.💖💖💖💖✔<<<<<298K/25°C
100kPa/1 atm
1 moldm-3
Enthalpy change of formation - correct answer.💖💖💖💖✔<<<<<The enthalpy change when 1
mole of a compound is formed from its constituent elements under standard conditions, with all
reactants and products in their standard states.
Enthalpy change of combustion - correct answer.💖💖💖💖✔<<<<<The enthalpy change when 1
mole of a substance is burned completely in oxygen.
Enthalpy change of atomisation - correct answer.💖💖💖💖✔<<<<<The enthalpy change that
accompanies the formation of 1 mole of gaseous atoms from the element in its standard state.
First ionisation enthalpy - correct answer.💖💖💖💖✔<<<<<The enthalpy change when 1 mole of
gaseous atoms loses 1 electron per atom to form 1 mole of gaseous 1+ ions.
Second ionisation enthalpy - correct answer.💖💖💖💖✔<<<<<The enthalpy change when 1 mole
of gaseous 1+ ions loses 1 electron per atom to form 1 mole of gaseous 2+ ions.
First electron affinity - correct answer.💖💖💖💖✔<<<<<The enthalpy change when 1 mole
gaseous atoms gains 1 electron per atom to form 1 mole of gaseous 1- ions.
Second electron affinity - correct answer.💖💖💖💖✔<<<<<The enthalpy change when 1 mole of
gaseous 1- ions gains 1 electron per atom to form 1 mole of gaseous 2- ions.
, Mean bond enthalpy - correct answer.💖💖💖💖✔<<<<<The enthalpy change when 1 mole of
gaseous molecules each breaks a covalent bond to form 2 gaseous ions or free radicals.
Lattice enthalpy of formation - correct answer.💖💖💖💖✔<<<<<The enthalpy change when 1 mole
of a solid ionic compound is formed from its gaseous ions.
Lattice enthalpy of dissociation - correct answer.💖💖💖💖✔<<<<<The enthalpy change when 1
mole of a solid ionic compound dissociates into its gaseous ions.
Enthalpy of hydration - correct answer.💖💖💖💖✔<<<<<The enthalpy change when 1 mole of
gaseous ions dissolves completely in water.
Enthalpy of solution - correct answer.💖💖💖💖✔<<<<<The enthalpy change when 1 mole of an
ionic solid dissolves in enough solvent to ensure that the dissolved ions are well separated and do not
interact with one another.
Enthalpy of vaporisation - correct answer.💖💖💖💖✔<<<<<The enthalpy change when 1 mole of a
liquid evaporates to form 1 mole of a gas.
Enthalpy of sublimation - correct answer.💖💖💖💖✔<<<<<The enthalpy change when 1 mole of a
solid sublimes to form 1 mole of a gas.
Why are ionisation enthalpies always positive (endothermic)? - correct
answer.💖💖💖💖✔<<<<<Energy needs to be put in to pull an electron away from the nucleus to
overcome the electrostatic attraction.
Why are first electron affinities always negative (exothermic)? - correct
answer.💖💖💖💖✔<<<<<Energy is given out when an electron is attracted to the positively
charged nucleus.
