General Thoughts (1 Viewer)

[Makematics]

yeah me too... didn't even see it as oxidation/reduction, i just said they both needed one electron for full shell therefore not sponaneous...

Lel better than me, i used the cell potentials table and somehow incorrectly found it to be spontaneous

 

[superSAIyan2]

only 2. you could also explain it by saying bromine has a greater tendency to oxidise in the presence of chlorine and hence will not reduce.

 

[RealiseNothing]

In the reaction chloride ions are oxidised to chlorine gas and bromine liquids is reduced to bromide ions.
Anode: 2Cl(-) ----> Cl2 + 2e- E(oxidation) = -1.36V
Cathode: Br2 + 2e- ----> Br- E(reduction) = 1.08V
cell potential is -0.28V <0 therefore nonspontanteous

I had exactly this yay.

 

[hayabusaboston]

NOO FUCK I FOUND 3 MORE MARKS I LOST

90/100 maximum raw

State rank gone for sure -_-

 

[KoshX87]

For the 2nd short answer page did you guys get:
a) Lead Sulphate (I wasn't too sure)
b) Ba2+ + 2Cl- --> BaCl2 (with states as aqueous)
c) I wrote that you would use a platinum rod and dip it into the solution. A green flame test would indicate copper. Anyone?

 

[superSAIyan2]

i got
a) Barium Shulfate
b) Pb2+ + 2Cl- = PbCl2
c) Add sodium hydroxide. Formation of blue precipitate suggests copper ions are present. To confirm dissolve precipitate in excess ammonia; a deep blue complex forms if copper is present.

KoshX87 How did u get a precipitate in aqueous state?

 

[hayabusaboston]

OK Im trying to recall all the mistakes I remember i did in the test, ive got so far:
-2 for MC
-1 or -2 for lead and silver nitrate q
-1 for spontaneous reaction q
-1 for equilibrium constant q
Possibly -2 for industrial 7 marker
-1 for one of the validity q's
-1 for another q I forgot


Can someone plz just list the harder q's, I forgot some of them, trying to remember my errors.

 

[KoshX87]

i got
a) Barium Shulfate
b) Pb2+ + 2Cl- = PbCl2
c) Add sodium hydroxide. Formation of blue precipitate suggests copper ions are present. To confirm dissolve precipitate in excess ammonia; a deep blue complex forms if copper is present.

KoshX87 How did u get a precipitate in aqueous state?

I went to the toilet and realised that, but i need to study for physics so i did a bit and didn't bother changing lol

 

[KoshX87]

And yes i realise i screwed that question. I might still get marks for the Copper part though

 

[leesh95]

How much would 67-68 raw align to?

 

[superSAIyan2]

Can someone plz just list the harder q's, I forgot some of them, trying to remember my errors.

Ozone question, microscopic membrane filters

 

[hayabusaboston]

Ozone question, microscopic membrane filters

Definitely got 6/6 and 4/4 for those, I was expecting an ozone question specifically and membrane filters I just felt I should know about them lol, those two things I was very well prepared for.

 

[leesh95]

How much would 67-68 raw align to?

bump

 

[integral95]

NOO FUCK I FOUND 3 MORE MARKS I LOST

90/100 maximum raw

State rank gone for sure -_-

lol I what I've heard of students getting raw marks of high 80s last year and that's still a state rank

 

[wannabesurgeon]

I thought the exam was hard. 50% of people left early in my school.

It wasn't impossible but not exactly that easy either.

Glad I'm not the only one..

 

[Queenroot]

i got
a) Barium Shulfate
b) Pb2+ + 2Cl- = PbCl2
c) Add sodium hydroxide. Formation of blue precipitate suggests copper ions are present. To confirm dissolve precipitate in excess ammonia; a deep blue complex forms if copper is present.
KoshX87 How did u get a precipitate in aqueous state?

I said sodium carbonate and a light blue precipitate would form and left it at that... Lol

 

[hayabusaboston]

lol I what I've heard of students getting raw marks of high 80s last year and that's still a state rank

U joking arent u? lol I will probs as the days go by find more errors I did anyway...

Fuck it, cant change what happened, focus on getting a band 6 in physics now.

 

[bangladesh]

I said sodium carbonate and a light blue precipitate would form and left it at that... Lol

It's sodium hydroxide. But yeah i said blue ppt. I think that should be enough for 2 marks.

So far I've lost like 5 marks.

 

[hayabusaboston]

It's sodium hydroxide. But yeah i said blue ppt. I think that should be enough for 2 marks.

So far I've lost like 5 marks.

In whole paper? Good job haha. inb4 state no 1 eh! haha

 

[technique]

was it lead sulfate or barium sulfate for precipitate 1?