CSSA chemistry (13 Viewers)

[Dylanamali]

Re: CSSA Chemistry 2011

lol no. Because you can't get it straight from crude oil.

+1

 

[Riproot]

umz, how did you go? sounds like you went well...

I found it quite challenging..

What was your answer for the HCl being added to BaOH and the resulting pH of the solution.

Also what was the answer of what is the use of the Geiger counter.

And just a checking thing: in MCs there was a question comparing sulfuric acid and HCl - my answer was they have the same H+ and the same pH. Is that what you got?

sulfuric acid had more h+ and lower pH because it can partially dissociate another h+ ion.

 

[Hermes1]

Re: CSSA Chemistry 2011

umz, how did you go? sounds like you went well...

I found it quite challenging..

What was your answer for the HCl being added to BaOH and the resulting pH of the solution.

Also what was the answer of what is the use of the Geiger counter.

And just a checking thing: in MCs there was a question comparing sulfuric acid and HCl - my answer was they have the same H+ and the same pH. Is that what you got?

no wouldnt sulfuric acid have a lower pH bcuz it is diprotic

 

[Dylanamali]

Re: CSSA Chemistry 2011

sulfuric acid had more h+ and lower pH because it can partially dissociate another h+ ion.

BUT. the concentration of the sulfuric was 0.25 and the conc of the HCl was 0.5

so if you do the calculation pH=-log(0.25x2), they have the same pH and also the same H+conc

 

[Hermes1]

Re: CSSA Chemistry 2011

sulfuric acid had more h+ and lower pH because it can partially dissociate another h+ ion.

lol riproot u were all depressed b4 this exam and now u look like u did quite well judging by ur answers.

 

[Alkanes]

Re: CSSA Chemistry 2011

Umm ethlyene is mainly obtained by cracking alkanes?

 

[umz93]

Re: CSSA Chemistry 2011

sulfuric acid had more h+ and lower pH because it can partially dissociate another h+ ion.

Dude r u srs? thats what i got
But people in my school said it was the same conc...

 

[Hermes1]

Re: CSSA Chemistry 2011

BUT. the concentration of the sulfuric was 0.25 and the conc of the HCl was 0.5

so if you do the calculation pH=-log(0.25x2), they have the same pH and also the same H+conc

oh ok i was going by the fact they had equal concentrations. but now i can see wif new info that u were right.

 

[Dylanamali]

Re: CSSA Chemistry 2011

lol riproot u were all depressed b4 this exam and now u look like u did quite well judging by ur answers.

hermes you do the CSSA chem exam?

 

[Hermes1]

Re: CSSA Chemistry 2011

hermes you do the CSSA chem exam?

no lol. i would hav been fuked if i had.

 

[Dylanamali]

Re: CSSA Chemistry 2011

Dude r u srs? thats what i got
But people in my school said it was the same conc...

yeah my they were both the same, once you did the simple calc.

 

[umz93]

Re: CSSA Chemistry 2011

umz, how did you go? sounds like you went well...

I found it quite challenging..

What was your answer for the HCl being added to BaOH and the resulting pH of the solution.

Also what was the answer of what is the use of the Geiger counter.

And just a checking thing: in MCs there was a question comparing sulfuric acid and HCl - my answer was they have the same H+ and the same pH. Is that what you got?

Yeah i went alrite, hopefully didnt make too many stupid mistakes Wbu?

 

[umz93]

Re: CSSA Chemistry 2011

!@#$% well whats done is done.

 

[Dylanamali]

Re: CSSA Chemistry 2011

Yeah i went alrite, hopefully didnt make too many stupid mistakes Wbu?

Very challenging I must say.. like the calculations were relatively difficult, some MC's were tricky, other than that e.g. the worded questions were quite simple and basic. But still dont think I did that great, minimum of 80% I'm thinking atm.

 

[Riproot]

lol riproot u were all depressed b4 this exam and now u look like u did quite well judging by ur answers.

I failed. I'm not that depressed I just know for a fact that I failed and I will go to rank 8. Because everyone else will get 70-96. :/

 

[umz93]

Re: CSSA Chemistry 2011

Yeah im about the same. Only question i couldnt do was the eqbm experiment cos i didnt study it :/

 

[Dylanamali]

Re: CSSA Chemistry 2011

How did people do the octane question???

This is how I went about doing it..
They provided us with the octane density e.g. 780g/L and they also provided us with the molar mass e.g. 144g/moL
So I said, in 1L of octane there is 780g of octane. No. of mols of octane = m/M = 780/144 = what ever the answer is.

And then the next question was like... how much energy is released from 1L of octane.
I then used my answer from part i) the no of mols of octane in 1L
In the equation it provided us a energy value e.g. 5000kJ/mol
so I just did 5000/no. of mols of octane in 1L

Next part I did a similar thing to ethanol e.g. got the no. of mols in 1L by doing the same method.
Then I did ratios ... e.g. ___no. of mols of octane = ____kJ = 10km
therefore this ____no. of mols of ethanol = _____kJ = how ever long.

 

[Dylanamali]

Re: CSSA Chemistry 2011

Yeah im about the same. Only question i couldnt do was the eqbm experiment cos i didnt study it :/

what was the eqbm experiment?? option?

 

[umz93]

Re: CSSA Chemistry 2011

Perfect!

 

[umz93]

Re: CSSA Chemistry 2011

what was the eqbm experiment?? option?

Yeah stupid industrial