CSSA chemistry (2 Viewers)

[zxreth]

Re: CSSA Chemistry 2011

Im the only one in my school doing chem (i do it via online so when you take the people from the other school in account its probs 15), only have 9 peolpe in year 12...

lol wtf

 

[Midnight_Lotus]

Re: CSSA Chemistry 2011

lol wtf

I was the same when i first went to the school :\

 

[maths94]

Re: CSSA Chemistry 2011

I was the same when i first went to the school :\

school rank? 500 + ?

 

[Midnight_Lotus]

Re: CSSA Chemistry 2011

Yup, the thing is i do bio and chem online and the school which hosts that is ranked about 300, so i have a combo

 

[RANK 1]

Re: CSSA Chemistry 2011

our school is ranked 98 but thats only cos last years yr 12 were godlike

 

[Joy_2575]

CSSA Chem 2011

My school doesn't use CSSA papers for Chem, Maths , Physics and ancient history..

however I am curious to know what was in the paper? obviously bcs it is considered one of the harder papers

any particular questions that were not the normal typical HSC questions? Please do share

Thanks in Advance

 

[imZerroo]

Re: CSSA Chemistry 2011

dropping chem = best decision of my hsc life!

picking chem when i was in yr 10, then persisting with it after i failed yr 11 yearlies,
worst decision i will ever make hopefully.

 

[jamesfirst]

I fucking wrote carbon. Fucking hell if that's actually write I will cry from happiness.

It is actually right, but the syllabus only talks about Sulfur and nitrogen oxides... so Idk


maybe if your teacher was generous, he'll give you a mark.

 

[jamesfirst]

Re: CSSA Chemistry 2011

And.. WOW 3 pages!! on a 5 marker .. I wrote through the whole pages and then half another.

I did a similar thing to Midnight however was not as specific with the various changes in equilibrium.

How can you write 3 pages?? When the space for your answer is allocated ?


I myself filled the whole thing. I just talked about Haber process, him helping the german movement, and the knowledge of equilibrium enhancing ...

 

[Askanison]

Re: CSSA Chemistry 2011

even though im over thinking this... i need a second opinion.
for the Ba(OH)2 and HCl question heres what i did

25mL of 0.75 mol/l HCl
10mL of 0.5 mol/l Ba(OH)2

when added
==> (0.75)(0.025)=(0.035)x ==> x= 0.5357 mol/l of HCl [new concentration] 0.0187 moles of HCl present in total
==> (0.5)(0.01)=(0.035)y ==> y= 0.142857 mol/l of Ba(OH)2 [new concentration] 0.005 moles of Ba(OH)2 present in total

2HCl + Ba(OH)2 ----> BaCl2 + 2H2O
2 : 1 1 : 2

for the neutralization to occur... the double the amount of Moles of Ba(OH)2 is needed for HCl.
2HCl + Ba(OH)2 ----> BaCl2 + 2H2O
0.01 0.005

in total there are 0.0187 moles of HCl, 0.01 of which are used up in the neutralization, leaving 0.0087 moles of unreacted HCl.
being able to fully ionize, the H+ concentration is that of the entire molecule.

THEREFORE pH = -log(0.0087)
= 2.06 ????

no one seems to agree with me
i think that was the D option

if i'm wrong, please explain

 

[Joy_2575]

Re: CSSA Chemistry 2011

even though im over thinking this... i need a second opinion.
for the Ba(OH)2 and HCl question heres what i did

25mL of 0.75 mol/l HCl
10mL of 0.5 mol/l Ba(OH)2

when added
==> (0.75)(0.025)=(0.035)x ==> x= 0.5357 mol/l of HCl [new concentration] 0.0187 moles of HCl present in total
==> (0.5)(0.01)=(0.035)y ==> y= 0.142857 mol/l of Ba(OH)2 [new concentration] 0.005 moles of Ba(OH)2 present in total

2HCl + Ba(OH)2 ----> BaCl2 + 2H2O
2 : 1 1 : 2

for the neutralization to occur... the double the amount of Moles of Ba(OH)2 is needed for HCl.
2HCl + Ba(OH)2 ----> BaCl2 + 2H2O
0.01 0.005

in total there are 0.0187 moles of HCl, 0.01 of which are used up in the neutralization, leaving 0.0087 moles of unreacted HCl.
being able to fully ionize, the H+ concentration is that of the entire molecule.

THEREFORE pH = -log(0.0087)
= 2.06 ????

no one seems to agree with me
i think that was the D option

if i'm wrong, please explain

Could you please re state the question that was in the test?

 

[Solie]

Re: CSSA Chemistry 2011

leaving 0.0087 moles of unreacted HCl.
being able to fully ionize, the H+ concentration is that of the entire molecule.

THEREFORE pH = -log(0.0087)

You used number of moles, rather than concentration. What you should have done is: c=0.0087/0.0035 , then log it. (35 mL is the total amount of liquid used).

 

[Joy_2575]

Re: CSSA Chemistry 2011

leaving 0.0087 moles of unreacted HCl.
being able to fully ionize, the H+ concentration is that of the entire molecule.

THEREFORE pH = -log(0.0087)

You used number of moles, rather than concentration. What you should have done is: c=0.0087/0.0035 , then log it. (35 mL is the total amount of liquid used).

Hey Solie
would you remember the question?

 

[Askanison]

Re: CSSA Chemistry 2011

leaving 0.0087 moles of unreacted HCl.
being able to fully ionize, the H+ concentration is that of the entire molecule.

THEREFORE pH = -log(0.0087)

You used number of moles, rather than concentration. What you should have done is: c=0.0087/0.0035 , then log it. (35 mL is the total amount of liquid used).

FARK
i realised that 3 seconds after posting...
there goes another mark...

thanks either way... stupid mistakes such as these always keep me from full marks. currently sitting on 97... hopefully

 

[Riproot]

my english co-ordinator did the same thing. UR NOT GOOD ENOUGH TO DO ADVANCED UR NOT GOOD ENOUGH etc etc. but 44 percent of kids get band 5 im guaranteed band 4...while in standard 6 percent get band 5 and like 12-18 get band 4, and l unfortunatly moved down standard coming top 20 /136 ...dumb bitch

My teacher just told me I had a bad attitude and that he didn't like me. :/

 

[Joy_2575]

what was the prac that was in the CSSA paper? and also did you guys have a question on dry cells?
We had to explain how a titration was carried out..lol

 

[muzeikchun852]

i dont think the trial was too difficult. im sure i made a few mistakes along the way. but overall fine. hoping i can pull off 85+.

 

[Dylanamali]

what was the prac that was in the CSSA paper? and also did you guys have a question on dry cells?
We had to explain how a titration was carried out..lol

We had a question on dry cell/lead acid cell vs another cell in terms of chemistry and impact on society.

 

[Riproot]

How can you write 3 pages?? When the space for your answer is allocated ?


I myself filled the whole thing. I just talked about Haber process, him helping the german movement, and the knowledge of equilibrium enhancing ...

Yeah I did that too. Btw, my teacher advised me to use an extra booklet as he hates my writing and told me to space and write big. Although I kinda didn't.

 

[Riproot]

We had a question on dry cell/lead acid cell vs another cell in terms of chemistry and impact on society.

Fucking forgot everything!!! Write the wrong equations!
Hopefully I get 2 marks for the impact on society.