Chemistry 9701/P22

[obsessedgenius]

@m2rulz143- you are thinking that the ethanoic acid will first react with NaOH and the remaining would react with the alcohol. The NaOH was added in the end, so whatever moles of Ethanoic acid it reacted with was the one that REMAINED after reaching equilibrium...

 

[zahraahmed]

hey a tip i have abt ur practical 34 it may sound weird but here it is and it really helped me
just go to your book rack and dig out your O levels ATP book it really helps!!!! first of all you begin to think its all easy so u are confident with ur experiment for example u get practice frm titration calculations and salt analysis as well as some information on other experiments like energetics etc....
it helps give u a strong base so u can easily get above 30 in practical

 

[AizaAnjum]

thanks =P

 

[histephenson007]

hey a tip i have abt ur practical 34 it may sound weird but here it is and it really helped me
just go to your book rack and dig out your O levels ATP book it really helps!!!! first of all you begin to think its all easy so u are confident with ur experiment for example u get practice frm titration calculations and salt analysis as well as some information on other experiments like energetics etc....
it helps give u a strong base so u can easily get above 30 in practical

Y didn't u say this last week??
before I messed up my practical??

 

[m2rulz143]

@m2rulz143- you are thinking that the ethanoic acid will first react with NaOH and the remaining would react with the alcohol. The NaOH was added in the end, so whatever moles of Ethanoic acid it reacted with was the one that REMAINED after reaching equilibrium...

Was it written there that they are adding it after reaching equillibrium and y would they than want us to find moles of naoh before and not after it have reached equillibrium if this is the case than grade threshhold will sure fall coz i've done almost every past paper and never came across such question..i am afraid now my p3 didnt went well and nw u guys are scaring me..

 

[zahraahmed]

hey ive been telling this to everyone besides last week was a fight with filza so everyone thought i was such a jerk..................and ppl told me u cant compare o levels with a levels but guys experiments are experiments...........its not theory we are comparing besides remember one thing in o levels u give titre as 29.5 but in a levels it HAS to be 29.50 to 2.d.p. only this is diff the rest is same same calculations..................same salt analysis......

 

[hassam]

:Yahoo!: :Yahoo!: :Yahoo!: :Yahoo!: :Yahoo!: :Yahoo!: :Yahoo!:

 

[zahraahmed]

hey wht happened y this yahoo smiley wen ppl are getting sad at their p22 knowing the silly mistakes done?

 

[power27]

what was the Full equation in the question
b/w
Ba02 + H2SO4

 

[Anonymousx3]

what was the Full equation in the question
b/w
Ba02 + H2SO4

BaO2 + H2SO4 ---> BaSO4 + H2O2

 

[boy2011]

i wrote carbonyl group in the last part of last questn whch asks fr function group?wil it b ryt?there was C=O group?

 

[ahmedrik1501]

hey what was that gaseous reagent in that barium wala question?

Co2

as Ba(OH)2+CO2(aq) >>>>> BaCO3+ H2O

 

[filza94]

hmm @ zahra watz rong y u telling evryone we had a fite i told u to forget it ufff...........!!!!

 

[hassam]

well wat was that empirical formula......18.9/16 : 81.1/56......ne we get the simplest ratio abt 1.22 which is approximately 1...so formula was BaO

 

[hassam]

well wat was that empirical formula......18.9/16 : 81.1/56......ne we get the simplest ratio abt 1.22 which is approximately 1...so formula was BaO

 

[histephenson007]

No...... the ratio was 0.6:1.2
So, it was 1:2
So, it was BaO2

 

[ahmedrik1501]

I think the paper was quite easy just messed up BaO2 wala part and the did addition instead of subtraction in bond enthalpy hence lost one marks of answer. Rest the paper was easy and MgSO4 is highly soluble in water hence we could have said it. Kc part was cake.... and got 2.25 as the answer.. Overall paper was good and yeah can we have written Carboxaylic acid in last part and chiral was 1 thats for sure......and GT i wished could be somewhere around 50........ :Yahoo!: :Yahoo!: :Yahoo!: :Yahoo!: :Yahoo!: :Yahoo!: :Yahoo!: :Yahoo!: :Yahoo!: :Yahoo!: :O: :O: :O: :O: :evil: :evil:
:O: :O: :O: :O: :O: :O: :O: :O: :wink: :wink:

 

[hassam]

it contained 18.9 percent oxygen......so y used 32.....did u ever use 32 in emp. formula detrmination from ur o levels till A level so y 2day

 

[ahmedrik1501]

No...... the ratio was 0.6:1.2
So, it was 1:2
So, it was BaO2

yeah it was 0.6:1.2
hence 1:2

it was for sure barium superoxide or rather bariumperoxide

 

[hassam]

GUYX.....justify ur ansers......tell me y u used 32 as mass for oxygen...thats wat m askin.....just tell me.....