AQA A-LEVEL CHEMISTRY – PRACTICALS
QUESTIONS WITH ANSWERS UPDATED 2025 -
2026
(1),Outline,how,to,prepare,a,Standard,Solution,in,a,Volumetric,Flask,(for,an,acid-base,titration).,,,ANS,-
1.,All,apparatus,rinsed,with,distilled,water.
2.,Solute,weighed,out,accurately,,on,a,weighing,boat,,using,a,balance,accurate,to,2,dp.
3.,Solid,placed,in,beaker,and,dissolved,in,about,100cm3,of,water.
4.,Weighing,boat,rinsed,with,a,small,quantity,of,water,and,washings,added,to,beaker,-
,or,,weighing,boat,should,be,reweighed,and,the,difference,calculated.
5.,Solution,transferred,to,a,250cm3,volumetric,flask.
6.,Beaker,rinsed,with,distilled,water,and,washings,added,to,volumetric,flask.
7.,Distilled,water,added,to,volumetric,flask,until,made,up,to,graduation,mark,-
,bottom,of,meniscus,should,rest,on,the,mark.,
-,If,mark,overshot,,solution,is,more,dilute,than,expected,=>,start,again.
8.,Volumetric,flask,then,inverted,20,times,to,ensure,thorough,mixing.
(1),Outline,how,to,carry,out,an,acid-base,titration.,,,ANS,-
1.,All,apparatus,rinsed,with,distilled,water,and,then,with,the,relevant,solution.
2.,Using,a,pipette,and,pipette,filler,,pipette,25cm3,of,NaOH,into,a,conical,flask.,Touch,surface,of,solution,
with,tip,of,pipette,to,ensure,correct,quantity,is,transferred.
,3.,Using,a,funnel,,fill,burette,with,acid,and,then,remove,funnel,
-
,otherwise,,some,drops,may,fall,through,the,titration,after,the,initial,reading,has,been,taken,=>,lower,volu
me,recorded,than,used.
4.,Allow,a,small,quantity,of,the,acid,to,flow,through,the,burette,to,ensure,jet,space,is,filled.,Note,initial,rea
ding,on,burette.
-,If,jet,space,not,filled,,titre,value,higher,than,volume,actually,added.
5.,Add,2-
3,drops,of,phenolphthalein,(or,another,suitable,indicator),to,the,conical,flask,and,place,it,on,a,white,tile,-
,can,see,colour,change,better.
6.,Add,acid,from,burette,into,conical,flask,,swirling,mixture,during,addition,,until,indicator,changes,colour,
(pink,--->,colourless).,
7.,During,titration,,rinse,sides,of,conical,flask,with,water,--->,ensures,all,acid,is,in,solution.
8.,Note,the,burette,reading.
9.,Repeat,experiment,but,add,acid,dropwise,(drop,by,drop),towards,the,end,point.
10.,Continue,repeating,until,at,least,two,concordant,results,obtained,(within,0.10cm3).
(1),Why,do,we,use,a,white,tile?,,,ANS,-To,see,indicator,colour,change,better.
(1),Why,is,a,conical,flask,used?,,,ANS,-Can,be,swirled,without,losing,any,solution.
, (1),Why,is,swirling,necessary?,,,ANS,-To,ensure,that,solutions,mix,and,so,react,completely.
(1),Why,does,rinsing,the,flask,with,water,not,affect,the,end,point?,,,ANS,-Water,does,not,react,---
>,doesn't,affect,number,of,moles,present.
(Other,1),Outline,how,to,carry,out,a,mass,change,experiment.,,,ANS,-
1.,Crucible,weighed,on,a,balance,and,its,mass,is,recorded,(mass,1).
2.,Some,sample,placed,in,the,crucible.
3.,Crucible,and,contents,reweighed,on,a,balance,and,its,mass,recorded,(mass,2).
4.,Sample,heated,strongly,in,Bunsen.
5.,Crucible,and,contents,reweighed,on,a,balance,and,its,mass,recorded.
6.,The,sample,heated,and,reweighed,until,mass,no,longer,changed,--->,ensures,reaction,completed.
(Other,1),Outline,apparatus,-,diagram.,,,ANS,-Include:
-,Bunsen.
-,Tripod.
-,Pipe-clay,triangle.
-,Crucible.
-,Lid.
-,HEAT.
(Other,1),What,things,would,we,use,mass,change,experiments,for?,,,ANS,-1.,Formulae,determination.
QUESTIONS WITH ANSWERS UPDATED 2025 -
2026
(1),Outline,how,to,prepare,a,Standard,Solution,in,a,Volumetric,Flask,(for,an,acid-base,titration).,,,ANS,-
1.,All,apparatus,rinsed,with,distilled,water.
2.,Solute,weighed,out,accurately,,on,a,weighing,boat,,using,a,balance,accurate,to,2,dp.
3.,Solid,placed,in,beaker,and,dissolved,in,about,100cm3,of,water.
4.,Weighing,boat,rinsed,with,a,small,quantity,of,water,and,washings,added,to,beaker,-
,or,,weighing,boat,should,be,reweighed,and,the,difference,calculated.
5.,Solution,transferred,to,a,250cm3,volumetric,flask.
6.,Beaker,rinsed,with,distilled,water,and,washings,added,to,volumetric,flask.
7.,Distilled,water,added,to,volumetric,flask,until,made,up,to,graduation,mark,-
,bottom,of,meniscus,should,rest,on,the,mark.,
-,If,mark,overshot,,solution,is,more,dilute,than,expected,=>,start,again.
8.,Volumetric,flask,then,inverted,20,times,to,ensure,thorough,mixing.
(1),Outline,how,to,carry,out,an,acid-base,titration.,,,ANS,-
1.,All,apparatus,rinsed,with,distilled,water,and,then,with,the,relevant,solution.
2.,Using,a,pipette,and,pipette,filler,,pipette,25cm3,of,NaOH,into,a,conical,flask.,Touch,surface,of,solution,
with,tip,of,pipette,to,ensure,correct,quantity,is,transferred.
,3.,Using,a,funnel,,fill,burette,with,acid,and,then,remove,funnel,
-
,otherwise,,some,drops,may,fall,through,the,titration,after,the,initial,reading,has,been,taken,=>,lower,volu
me,recorded,than,used.
4.,Allow,a,small,quantity,of,the,acid,to,flow,through,the,burette,to,ensure,jet,space,is,filled.,Note,initial,rea
ding,on,burette.
-,If,jet,space,not,filled,,titre,value,higher,than,volume,actually,added.
5.,Add,2-
3,drops,of,phenolphthalein,(or,another,suitable,indicator),to,the,conical,flask,and,place,it,on,a,white,tile,-
,can,see,colour,change,better.
6.,Add,acid,from,burette,into,conical,flask,,swirling,mixture,during,addition,,until,indicator,changes,colour,
(pink,--->,colourless).,
7.,During,titration,,rinse,sides,of,conical,flask,with,water,--->,ensures,all,acid,is,in,solution.
8.,Note,the,burette,reading.
9.,Repeat,experiment,but,add,acid,dropwise,(drop,by,drop),towards,the,end,point.
10.,Continue,repeating,until,at,least,two,concordant,results,obtained,(within,0.10cm3).
(1),Why,do,we,use,a,white,tile?,,,ANS,-To,see,indicator,colour,change,better.
(1),Why,is,a,conical,flask,used?,,,ANS,-Can,be,swirled,without,losing,any,solution.
, (1),Why,is,swirling,necessary?,,,ANS,-To,ensure,that,solutions,mix,and,so,react,completely.
(1),Why,does,rinsing,the,flask,with,water,not,affect,the,end,point?,,,ANS,-Water,does,not,react,---
>,doesn't,affect,number,of,moles,present.
(Other,1),Outline,how,to,carry,out,a,mass,change,experiment.,,,ANS,-
1.,Crucible,weighed,on,a,balance,and,its,mass,is,recorded,(mass,1).
2.,Some,sample,placed,in,the,crucible.
3.,Crucible,and,contents,reweighed,on,a,balance,and,its,mass,recorded,(mass,2).
4.,Sample,heated,strongly,in,Bunsen.
5.,Crucible,and,contents,reweighed,on,a,balance,and,its,mass,recorded.
6.,The,sample,heated,and,reweighed,until,mass,no,longer,changed,--->,ensures,reaction,completed.
(Other,1),Outline,apparatus,-,diagram.,,,ANS,-Include:
-,Bunsen.
-,Tripod.
-,Pipe-clay,triangle.
-,Crucible.
-,Lid.
-,HEAT.
(Other,1),What,things,would,we,use,mass,change,experiments,for?,,,ANS,-1.,Formulae,determination.
