CSSA 2007 Chemistry Trial Examination thoughts (3 Viewers)

[Forbidden.]

How was it today?

Happy you'll get over 30%? Crazy ?
Couldn't remember that biopolymer you learnt ages ago in the Production of Materials topic that was 'degrading in your head' ?
Did your knowledge of the BOD practical 'dissolve' quickly ?


I thought so too.

Our teacher gave us his version of the Shipwrecks and Salvage question paper because we didn't finish the whole course.

 

[wrxsti]

okay from a guy who loves chemistry ..... it was challenging.... but really good.... very nice test hard than all CSSA papers before
question 14 MADE NO SENSE WHATSOEVA and was just shocking...... i rote D
because an oxygen free radial and an oxygen ATOM are exactly the same.... finished the test in 1hour and 30 mins ...
now i got till thursday untill the complete opposite happens where i get depressed that i stuffed up in physics

 

[Forbidden.]

okay from a guy who loves chemistry ..... it was challenging.... but really good.... very nice test hard than all CSSA papers before
question 14 MADE NO SENSE WHATSOEVA and was just shocking...... i rote D
because an oxygen free radial and an oxygen ATOM are exactly the same.... finished the test in 1hour and 30 mins ...
now i got till thursday untill the complete opposite happens where i get depressed that i stuffed up in physics

I finished in such a short time too lol.
Throughout the remaining hour I did almost nothing at all.

Spoiler

For Q14) An oxygen radical contains free electrons to pair up with but the diatomic oxygen atom doesn't, I chose A

 

[Bonarius]

yup, i had an hour left too, we didn't have to do 16 marks worth out of the last section cause we hadn't finished. I thought it was a good paper though. the BOD question not so nice

 

[BIGTYMA]

I thought i did well in this paper. i thought the hardness part was the last question of shipwrecks.

 

[beentherdunthat]

I finished in such a short time too lol.
Throughout the remaining hour I did almost nothing at all.

Spoiler

For Q14) An oxygen radical contains free electrons to pair up with but the diatomic oxygen atom doesn't, I chose A

Yes... I chose A too
Hey omg you know that question for working out the percentage of phosporous... you just had to do 0.23 (whatever it was) / 4.1 (whatever it was ahahaha) and multiply by 100... CAN YOU BELIEVE IT... (luckily, in a spontaneous burst of madness, i done this...)

 

[wrxsti]

Yes... I chose A too
Hey omg you know that question for working out the percentage of phosporous... you just had to do 0.23 (whatever it was) / 4.1 (whatever it was ahahaha) and multiply by 100... CAN YOU BELIEVE IT... (luckily, in a spontaneous burst of madness, i done this...)

Nah its not. you need to calculate the phosphorus content... of the 0.2 grams or wuteva you find the number of moles...... blah blah blah.... in the end u get an answer
that answer / 4.1 and i remember answer is approx 1.3%

Also i dont think for 14) its gana be "a" i reckon its "d" it says oxygen free redical and an Oxygen ATOM clearly says atom...... :S so really an oxygen ATOM and free radical oxygen are the same... :S (see the diatomic oxygen would not be a MOLECULE)
GAY QUESTION ANYWAY !

 

[beentherdunthat]

1)Nah its not. you need to calculate the phosphorus content... of the 0.2 grams or wuteva you find the number of moles...... blah blah blah.... in the end u get an answer
that answer / 4.1 and i remember answer is approx 1.3%

2) Also i dont think for 14) its gana be "a" i reckon its "d" it says oxygen free redical and an Oxygen ATOM clearly says atom...... :S so really an oxygen ATOM and free radical oxygen are the same... :S (see the diatomic oxygen would not be a MOLECULE)
GAY QUESTION ANYWAY !

haha... 1) My teacher told me that was the right way to do (like i said just a spark of madness)
But how did you work out the number of moles?

2) The OXYGEN atom is a DIATOMIC MOLECULE... (yes, yes, molecule, not radical otherwise it would SPECIFY and idenitify it as a radical by writing Oxygen radical)... hence it is different...

 

[Forbidden.]

Nah its not. you need to calculate the phosphorus content... of the 0.2 grams or wuteva you find the number of moles...... blah blah blah.... in the end u get an answer
that answer / 4.1 and i remember answer is approx 1.3%

Also i dont think for 14) its gana be "a" i reckon its "d" it says oxygen free redical and an Oxygen ATOM clearly says atom...... :S so really an oxygen ATOM and free radical oxygen are the same... :S (see the diatomic oxygen would not be a MOLECULE)
GAY QUESTION ANYWAY !

i treated it like a fertiliser question

 

[beentherdunthat]

i treated it like a fertiliser question

:wave: How'd you do it???
Enlighten me, coz even though my teacher says I got it right, I don't see the logic behind it.

 

[Forbidden.]

:wave: How'd you do it???
Enlighten me, coz even though my teacher says I got it right, I don't see the logic behind it.

mass of phosphorous = (mass of precipitate x molecular weight of phosphorous) / molecular weight of that CaPO thingy

% mass of phosphorous = mass of phosphorous/mass of precipitate x 100

thats how i did

 

[beentherdunthat]

mass of phosphorous = (mass of precipitate x molecular weight of phosphorous) / molecular weight of that CaPO thingy

% mass of phosphorous = mass of phosphorous/mass of precipitate x 100

thats how i did

nonononononono. Mass of precipitate x mw = MOLES...

Moles / Molecular weight??? Does not sound right...

 

[wrxsti]

ok the thing was Ca2P207
ok? the whole fertiliser thing was 4.2g
the mass of Ca2P2O7 was somefing like 1.2g
now Molecular mass of Ca2P2O7 is roughly (40+40+31+31+16(times 7) )
which u get like 254
now moles = mass / MM
so 1.2 / 254
Moles = 0.00472 now moles of P2
Moles = mass/MM
so
0.00472 = mass/62 mass = 0.29264
now 0.29264 / 4.2 times 100 which is 6%..... but mmhmmm.... i got 1.3% in the test and i checked it like a billion times.,,,,, i mustve done some calculation error here....... I HOPE !

 

[2opinion8d]

it was indeed really challenging... not just those copy paste syllabus questions that we're all used to...

after the exam (in the car on the way home) i was like damn why didn't i talk about how australia has plently of sunshine and land for growing crops for ethanol production/ queesland/ sugarcane etc.... in the exam i just went on and on about hows its renewable etc... completely ignored "Australia"

for that calcium phosphate question i got something like 0.64% phosphorus???

For the K question i got 7. something

For that titration i got an abnormally low concentration... i was a bit sleepy during the exam and i got something like 0.09.... I think..

and yeah i put D for that MC 14... it clearly said oxygen atom. The oxygen atom and free radical are the same thing.

 

[wrxsti]

For phosphate content I found the percentage in the CaP thingy, then times that by the percentage of precipitate in 4. whatever grams of washing powder used.

I think I got 0.0127 something..know why? I forgot to times my final friggin' answer by 100 didn't I!!
Out of 2 marks, considering, I did all the working for the parts before, do you reckon I'll lose many? I hate making stupid mistakes!

i got 0.0127 in the est........ times by 100 you get 1.27% which is approx 1.3%
your teacher will give you 1 mark....... though you should get 1.5 ..... stupid HSC markers dont give half marks......

 

[Martyno1]

I got 1.3% for that gravimetric analysis question...

and for question 14 I put D. As the oxygen atom = oxygen free radical.

 

[Chinmoku03]

How was it today?

Happy you'll get over 30%? Crazy ?
Couldn't remember that biopolymer you learnt ages ago in the Production of Materials topic that was 'degrading in your head' ?
Did your knowledge of the BOD practical 'dissolve' quickly ?


I thought so too.

Our teacher gave us his version of the Shipwrecks and Salvage question paper because we didn't finish the whole course.

The way you put the biopolymer question holds true for me lol XD Tho I'm glad it's only worth 4 marks ^.^;

I'm sooo fucking pissed that not a single extended response question was devoted to CFC's. God, to think I got up early today to review the Cl radical cycle equations... >.<;

 

[markymark1990]

Hey does anyone have the actual chemistry exam paper from today?...or at least remember any of the questions? If u do could u please message me or email me at marky_mark1990@hotmail.com

I would much appreciate it! Thanks everyone.

 

[Martyno1]

Hey does anyone have the actual chemistry exam paper from today?...or at least remember any of the questions? If u do could u please message me or email me at marky_mark1990@hotmail.com

I would much appreciate it! Thanks everyone.

... :|

 

[wrxsti]

... :|

lol......