How did it go ? CSSA trial (2 Viewers)

[Ragerunner]

personally i found it pretty easy. but the question that i never expected was the barium content question

 

[Huy]

I screwed up

Multiple choice: Question 9.
About the volume of CO2.

Petrol extender/Ethanol.
Solvay process/Environmental effects
Ozone/CFCs
Diaphragm process.
Lowry-Bronsted
Polyethylene/Cellulose

Basically ... ALL OF IT
I hope I get some marks for the BS I wrote

They were the important ones too!
There goes my top5 ranking.

 

[Ragerunner]

haha i remember question 9. my answer was so messed up. i ended up getting C. i guessed it. i thought it was A but then it couldn't be that easy and i never used the HCL in my result.

volume of CO2 was

n=15/44
V = 0.34 x 24.79 = 8.45L

petrol extender i just made up stuff that sounds good. like it contains water and can corrode the engine

CFC question i killed it. wrote right to the bottom of the page

 

[Chand]

i think i went pretty good, except for my option...for that calcium carbonate what did u guys get as an answer?

 

[funkychickie]

easy peesy

omg i found that so so easy.. but i dunno if it was just me!! yeh does anyone do forensic chem?
we had another part to the last question cause we havent finished... it was basically the same as the part e) that was changed!

 

[~TeLEpAtHeTiC~]

i went ok..
i finished 1.5 hours into exam... had to sit there for AGGGEEESSS
oh well..
i rekon i got 60 - 70 though
i guess sum multiple chioce.
long extended responses my writing was good but i forgot alot of equation
cfc was really good
options.. pfft... that i went bad in cause we havn't done much in class but we were meant to do it all.
oh well see how i go
good luck to all of u

 

[Rand]

OMG that was hard!!

what was the deal with that wine question??

was it suppoesed to be a buffer or what?

Heaps of little things to lose marks on

Oh well

 

[underthesun]

Which calcium carbonate question?

btw, What did you guys / girls put in for that isomers multiple choice? It should be (a) right?

Originally posted by Ragerunner
haha i remember question 9. my answer was so messed up. i ended up getting C. i guessed it. i thought it was A but then it couldn't be that easy and i never used the HCL in my result.

volume of CO2 was

n=15/44
V = 0.34 x 24.79 = 8.45L

petrol extender i just made up stuff that sounds good. like it contains water and can corrode the engine

CFC question i killed it. wrote right to the bottom of the page

What was question 9?

You're right with the volume of gas, cuz i got that too .

btw petrol extender is ethanol, so I think it should be working as a solvent that cleans the engine, not corrode it

 

[underthesun]

Originally posted by Rand
OMG that was hard!!

what was the deal with that wine question??

was it suppoesed to be a buffer or what?

Heaps of little things to lose marks on

Oh well

I dont think it's a buffer, because it takes the H30+, so it should reduce the acidity, yeh?

But i also wrote about the K+ remainders that takes away the OH- of the water.. so how would I know

So, maybe it does not really change the pH, all it does is just prevent oxidation or something, as it said.

 

[Ragerunner]

the wine question i put that its an equilibrium reaction and increase in HSO3 results in shift to the right and decrease in H3O+ iions therefore pH goes higher

 

[Chand]

umm..the calcium carbonate was yeah calculating the CO2 but cause there was only 0.05 moles of HCL....and it was a ratio of 2:1..it limited the CO2....i dun remember what i got though...not sure if i even did it rite

 

[Ragerunner]

there was 1.00 mol/L of HCL if i remember correctly.

underthesun can u explain how you got C as your answer ? even though i guesseed it rught

 

[Ragerunner]

and was it me or was there NOT a single titration question in the whole exam ? ??

bizarre

 

[underthesun]

It was :

Na2(CO3)2 + 2HCl -> 2NaCl + H2O + 2CO2

not sure.. confusing

 

[Ragerunner]

???

wasn't it calcium carbonate ?

i mean how did you come up wih the figure 0.62 as an answer ?

 

[underthesun]

I got 8.449 L, so im not talking about that question 9 multiple choice question

for that, I got A, and the above equation doesn't really describe it well, but I can't balance it myself..

Anyways, if one reaction produces one mole, then the answer isn't on the list. I doubled the answer, and it was A, so I just assume that there were 2 moles of product from one reaction, and pick A. And the last, but worst case, is if not all of the products were used to completion etc, and the answer is one of the other 3..

damn*

 

[Chand]

CaCO3+2HCl ---> CO2+H20+CaCl2

and it said i think that there was 0.05 L of HCL with a molarity of 1 mol/L....using that, i calculated the moles which was 0.05, divided it by two bc of teh ratio, ie. 0.025 then times it by 24.79 and got 0.62

 

[underthesun]

Oh yeah, in that case,

Ca(CO3)2 + 2HCl -> CaCl2 + H2O + 2CO2

something like that, i couldn't balance it with all the [ size = 1 ] mess here.. but the only number that was there that was fit was A, and others seems strange..

 

[underthesun]

never mind, i think i got it wrong

 

[Ragerunner]

i think the answer was C