GT for Chemistry paper 22 AS.

[TheMan123]

ppl 4 Al and Cl did you'll write AlCl3 or Al2Cl6? I wrote AlCl3

I think its AlCl3 because Al2Cl6 is formed only in very high temperatures, but they may accept both

 

[ishan123]

Q1
i wrote sodium for the colored flame with chlorine.. not sure
2Al(s) + 3Cl2(g)--> AlCl3(s)
when this reaction occurs, the pale yellow color of the gas disappears and a white solid is formed
Argon doesn't react as it is in a stable elemental state because of its full octet.
Sodium dissolves pH 7
Aluminum dissolves pH 6-- ?..
Silicon reacts pH 3
Reaction is redox/disproportionation
Sulfur- 2 lone pairs
Nitrogen- 1 lone pair
Bond A is smaller due to the presence of 2 lone pairs compared to just 1, thus repelling bond pairs more.

Q2
Ch3OH(l)+3/2O2(g) = CO2(g) + 2H2O(l)
enthalpy change is -129 kJ/mol
increase in pressure increases rate of formation due to increased interaction/collisions between reactant molecules
increase in temp. increases rate of formation due to more particles having energy greater than Ea
presence of catalyst increases rate of formation as it lowers Ea
_______The reaction was an irreversible reaction, so the concept of equilibrium shifts cannot be incorporated________

Q3
I don't remember the exact structure of the compound but
to the left, an ester with the tail -CO2H groups were formed
to the right, an ester with the middle -OH group was formed
straight down, an alkene was formed with the elimination of the middle -OH group and a hydrogen from one of the neighboring C's
alkene + cool, dilute KMnO4 gave you a product with the double bond removed and a diol
alkene + hot, conc. KMnO4 gives you something i'm not sure of!
NOTE--- I have just talked about the parts of the compounds that have changed, everything else is meant to be the same
I cannot recall the reaction we had to write the types of...
the optical isomer was easy
My cis-trans isomers looked the same as Pal_1010's..-- Am I right?

For the fourth que,
Na--- -CO2H and -OH
K2Cr2O7 & heat---- -OH and -CHO
NaHCO3--- -CO2H-- (I remember cuz its a test :O)
i got the functional group as -oh -- alcohol
moles of hydrogen atoms as 6.67x10^-3
proved the presence of 2 -OH groups by showing the ration of R-OH
and the presence of a ketone group.
The structure of G was CH2(OH)C=OCH2(OH), drawn of course!
the empirical formula was C6H8O7.... But I wrote C7H9O8.. if I have made a mistake in multiplying the correct base ratio of CHO- C1H1.3O1.17 with a factor, do you think I can get at least 2/3 marks?.. :/



Guys, Do correct me where necessary..

 

[floral123]

Wat do u mean appear in planning paper??
Commercial use was for the ester PERFUMES ,FOOD FLAVOURING

i wrote solvents...??

 

[angelicsuccubus]

spot on

awh damnit.. that means i lost the pressure and temperature marks -_- ... goodjob cie, tricking people!

 

[floral123]

I hadn't notice it was SKELETAL formula that was asked for the cis-trans isomer(silly mistake I know) but I saw it like when 5 mins was left, and I hastily drew these. Do you think I'll get my marks?

guys i drew the same but dint show OOH coz i thought it was cis coz of H and trans coz of H so i dint write -OOH.........?

 

[angelicsuccubus]

what was the emperical formula? Somehow I ended up with C6H8O7

 

[aditya avhad]

Organic sucked big tym:'(
The rest was OK!I expected a question for electrolysis this tym

Same Here..

 

[angelicsuccubus]

Considering Ive already lost 8 marks over silly mistakes.. I don't think the GT would cross 50

 

[Pals_1010]

what was the emperical formula? Somehow I ended up with C6H8O7

Yup I got that too

 

[angelicsuccubus]

Yup I got that too

good, cause I recalculated right now and it has to be C6H8O7 !

 

[JulyMei]

what's the total mark for paper 2?

 

[ishan123]

what's the total mark for paper 2?

60..

 

[WhereAmazingHappens]

They asked which element burns in colored flame in Chlorine. Only Sulfur burns in with a colored flame in Chlorine.

Sulfur burns with a blue flame.

Cheers

 

[WhereAmazingHappens]

ppl wats d element dat burns with a coloured flame . ppr ws a bit tough

They asked which element burns in colored flame in Chlorine. Only Sulfur burns in with a colored flame in Chlorine.

Sulfur burns with a blue flame.

Cheers ​

 

[littlecloud11]

what was the empirical formula in q3??

C6H8O7

 

[littlecloud11]

They asked which element burns in colored flame in Chlorine. Only Sulfur burns in with a colored flame in Chlorine.

Sulfur burns with a blue flame.

Cheers

there was no chlorine mentioned in the question.
only which element burns with a colored flame, and the possible answers were. sodium (yellow), phosphorous (blue), sulfur (yellow)

 

[littlecloud11]

P5...I wrote as a food preservative:S

esters are not used as preservatives. solvents, perfumes, flavorings were some of the possible answers

 

[good man12]

They asked which element burns in colored flame in Chlorine. Only Sulfur burns in with a colored flame in Chlorine.​

​

Sulfur burns with a blue flame.​

​

Cheers ​

in many text books and on wikipedia it says sodium burns in chorine in a yellow flame.....

 

[angelicsuccubus]

Q3
I don't remember the exact structure of the compound but
to the left, an ester with the tail -CO2H groups were formed
to the right, an ester with the middle -OH group was formed
straight down, an alkene was formed with the elimination of the middle -OH group and a hydrogen from one of the neighboring C's
alkene + cool, dilute KMnO4 gave you a product with the double bond removed and a diol
alkene + hot, conc. KMnO4 gives you something i'm not sure of!

Q3 answers:

HO2CCH2CH(OH)CO2H + CH3OH----------->CH3O2CCH2CH(OH)CO2CH3
HO2CCH2CH(OH)CO2H + CH3CO2H-------->HO2CCH2CH(CO2H)O2CCH3
HO2CCH2CH(OH)CO2H + conc. H2SO4----->HO2CCH=CHCO2H

HO2CCH=CHCO2H + hot conc. KMnO4----->HO2CCHO
HO2CCH=CHCO2H + cold dil. KMnO4------->HO2CCH(OH)CH(OH)CO2H
HO2CCH=CHCO2H + steam/H3PO4--------->I did this one wrong =[.. but it should be HO2CCH2CH(OH)CO2H

 

[Pals_1010]

there was no chlorine mentioned in the question.
only which element burns with a colored flame, and the possible answers were. sodium (yellow), phosphorous (blue), sulfur (yellow)

Yeah it was sodium