Aqa A Level Chemistry 3.1.8 – Thermodynamics Questions With Accurate Answers.

AQA A LEVEL CHEMISTRY 3.1.8 – THERMODYNAMICS
QUESTIONS WITH ACCURATE ANSWERS.

What,are,standard,conditions?,,,ANS,-298K/25°C

100kPa/1,atm

1,moldm-3



Enthalpy,change,of,formation,,,ANS,-
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,,,ANS,-
The,enthalpy,change,when,1,mole,of,a,substance,is,burned,completely,in,oxygen.



Enthalpy,change,of,atomisation,,,ANS,-
The,enthalpy,change,that,accompanies,the,formation,of,1,mole,of,gaseous,atoms,from,the,element,in,its,s
tandard,state.



First,ionisation,enthalpy,,,ANS,-
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,,,ANS,-
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,,,ANS,-
The,enthalpy,change,when,1,mole,gaseous,atoms,gains,1,electron,per,atom,to,form,1,mole,of,gaseous,1-
,ions.




Second,electron,affinity,,,ANS,-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,,,ANS,-
The,enthalpy,change,when,1,mole,of,gaseous,molecules,each,breaks,a,covalent,bond,to,form,2,gaseous,io
ns,or,free,radicals.



Lattice,enthalpy,of,formation,,,ANS,-
The,enthalpy,change,when,1,mole,of,a,solid,ionic,compound,is,formed,from,its,gaseous,ions.



Lattice,enthalpy,of,dissociation,,,ANS,-
The,enthalpy,change,when,1,mole,of,a,solid,ionic,compound,dissociates,into,its,gaseous,ions.



Enthalpy,of,hydration,,,ANS,-
The,enthalpy,change,when,1,mole,of,gaseous,ions,dissolves,completely,in,water.



Enthalpy,of,solution,,,ANS,-
The,enthalpy,change,when,1,mole,of,an,ionic,solid,dissolves,in,enough,solvent,to,ensure,that,the,dissolve
d,ions,are,well,separated,and,do,not,interact,with,one,another.



Enthalpy,of,vaporisation,,,ANS,-
The,enthalpy,change,when,1,mole,of,a,liquid,evaporates,to,form,1,mole,of,a,gas.



Enthalpy,of,sublimation,,,ANS,-
The,enthalpy,change,when,1,mole,of,a,solid,sublimes,to,form,1,mole,of,a,gas.



Why,are,ionisation,enthalpies,always,positive,(endothermic)?,,,ANS,-
Energy,needs,to,be,put,in,to,pull,an,electron,away,from,the,nucleus,to,overcome,the,electrostatic,attracti
on.



Why,are,first,electron,affinities,always,negative,(exothermic)?,,,ANS,-
Energy,is,given,out,when,an,electron,is,attracted,to,the,positively,charged,nucleus.



Why,are,second,electron,affinities,and,onwards,always,positive,(endothermic)?,,,ANS,-
Energy,needs,to,be,put,in,to,overcome,the,repulsion,between,an,electron,and,a,negatively,charged,ion.