Edexcel Chemistry Unit 4 (12th June 2013). Revision and Post Exam Discussions.

[NiazK98]

How is everyone's preparation going?

 

[PUSHPAK1321]

Well, Unit 4 is kinda easy. I am currently doing my final revision. The only chapter I am afraid about is the one about acid & bases. The chapter is easy but sometime calculations regarding buffer can be a bit tricky. Checkout the question in June 2012, it was somewhat difficult.

 

[qstar.inc]

Any notes?

 

[georgewest28]

well howd everyone find it?

 

[Choco<3]

well howd everyone find it?

The pattern was easy..but It was just okay fr me.. wbu?

 

[Shah...]

the ppr was horrible..srslyyy..i didnot like it at all..
got some ques..
what was the rate eqn..nd what was the value for the total entropy..also..the graph in the last question..was it a straight line..nd why does the phenolphtalin change color when the conc was 50cm3 and methyl yellow changes color,,when the conc was 25cm3.
if anyone here remembers any of these answers..plz reply..nd also what do u think the grade boundary for A* or A will be?

 

[georgewest28]

the ppr was horrible..srslyyy..i didnot like it at all..
got some ques..
what was the rate eqn..nd what was the value for the total entropy..also..the graph in the last question..was it a straight line..nd why does the phenolphtalin change color when the conc was 50cm3 and methyl yellow changes color,,when the conc was 25cm3.
if anyone here remembers any of these answers..plz reply..nd also what do u think the grade boundary for A* or A will be?

it was a hard paper.
rate quation was both first order
total etropy was likw -167
straighline graph
the ph range was slower, so less needed
what did people get for k?

 

[NiazK98]

the ppr was horrible..srslyyy..i didnot like it at all..
got some ques..
what was the rate eqn..nd what was the value for the total entropy..also..the graph in the last question..was it a straight line..nd why does the phenolphtalin change color when the conc was 50cm3 and methyl yellow changes color,,when the conc was 25cm3.
if anyone here remembers any of these answers..plz reply..nd also what do u think the grade boundary for A* or A will be?

Rate Eqn: Both were first order
Total Entropy: It was around 700 for me. System was -100 something and Surrounding was around 900. I'm not sure about this answer though. But I'm sure that we have to multiply the entropy of hydrogen by 2 ( 2xthe value given in databooklet).
Grapgh: Straight line.
Phenolpthalein Volume Qs: I left it blank. It was a 2 mark question, i just wrote the indicators range. Hopefully i'll get 1 from there.

The paper was easy but compared to the past papers it was a bit difficult. Imo they might give an A* for 78 and A for 68.

 

[Dead soul]

Entropy of system was -163.2 and surrounding was +959..total=795.8..
what was the value of activation energy? sme where like 38220 (in joules)?
n there was a MCQ, relating to indicators methyl orange n phenolphthalein, was the answer methyl orange but not with phenolphthalein?

what was da value of pH?
Is it 2.79?

 

[Dead soul]

it was a hard paper.
rate quation was both first order
total etropy was likw -167
straighline graph
the ph range was slower, so less needed
what did people get for k?

I got k=1.75*10^-3

 

[Choco<3]

I got k=1.75*10^-3

Activation energy was 37500 for me.

 

[Aaron Rodrgp]

it was just the negative gradient value into 8.31 (units J or KJ per mole)

 

[NiazK98]

Entropy of system was -163.2 and surrounding was +959..total=795.8..
what was the value of activation energy? sme where like 38220 (in joules)?
n there was a MCQ, relating to indicators methyl orange n phenolphthalein, was the answer methyl orange but not with phenolphthalein?

what was da value of pH?
Is it 2.79?

YEAH! All of my answers matched with you

 

[Xainab]

The organic section was confusing too. What were steps 1 & 2 in stage 2?

 

[Xainab]

The organic section was confusing too. What were steps 1 & 2 in stage 2?

And the mechanism was SN2, right?

 

[Xainab]

On amd more qs, why is it more correct to measure the ph of sodium ethandiote and not the acid?

 

[UmaKandasamy]

oh i think the rate equation was first order with respect to S2O8 only..not second order..

 

[Dead soul]

And the mechanism was SN2, right?

yeah, I gues it was!

 

[Choco<3]

Can anyone plz remind me of all the questions step by step.. i really need to make an estimate of the marks I'm gonna get...really tensed..plz anyone??

 

[Shah...]

Can anyone plz remind me of all the questions step by step.. i really need to make an estimate of the marks I'm gonna get...really tensed..plz anyone??

all i can do is like ur post..cuz i myself want the same help from ppl here..?