CSSA chemistry (5 Viewers)

[_deloso]

Re: CSSA Chemistry 2011

so whats the answer????

It should be the same pH and the same H+ concentration right..
-log(0.25x2) = -log(0.5)

Nope. well from riproots explanation.. I think h2so4 would produce less h+ thus less h+ concentration and greater pH than HCl. not entirely 100% on this one.

 

[Riproot]

Oh yeah the UV question. I got that one. I guessed the other calculation one in the MC is what I meant.

 

[Dylanamali]

Re: CSSA Chemistry 2011

relatively str8 forward. for the carbon monoxide one i got it was very dangerous :S but everyone seems to be getting differently. penis.

oh that damn ozone shit. there was one page missing in my notes and it had that specific dot point which was asked (the measuring ozone shit). i sunk into my chair once i saw it.

other than that, expecting above 85

Preety tank to get 85.. I said that it was very dangeroous with an answer of like 340 or soemthing LOL, but that was coz i didnt convert metres cubed properly.. =/

Ozone haha, that was all like TOMS and spectrophotometers and stuff.

 

[UnrealAnchovies]

Re: CSSA Chemistry 2011

i put same ph and concentration

 

[Dylanamali]

Re: CSSA Chemistry 2011

naoh draws in water from its surroundings (hygroscopic)

+1 except I didn't use that nice word =( haha.

 

[Dylanamali]

Re: CSSA Chemistry 2011

i put same ph and concentration

Unreal.. do you remember your answers for the MCs

Geiger counter usage?

adding HCl to BaOH and the resulting pH

Also the pH of lemon juice and the dilution one.

 

[_deloso]

Re: CSSA Chemistry 2011

completely left out the question on equilibrium in industrial chem... I was thinking of doing the co2 (aq) <-> co2 (aq) then talk about h2co3 equilibirum and also though of doing the haber process.. but I didnt cos we havent done the experiment. Just read the experiment in my prac book and it involved copper nitrate and potassium iodide to produce solid copper iodide and iodine (aq).. FAHHHHH!!!

 

[UnrealAnchovies]

Re: CSSA Chemistry 2011

aww man i hope i got the carbon monoxide thing. do they give marks for correct working out?

 

[Dylanamali]

Re: CSSA Chemistry 2011

aww man i hope i got the carbon monoxide thing. do they give marks for correct working out?

you should.. I think i only made the mistake of not converting metres cubed, so I'm hoping my chem teacher is nice and gives me like 3/4

 

[UnrealAnchovies]

Re: CSSA Chemistry 2011

Unreal.. do you remember your answers for the MCs

Geiger counter usage?

adding HCl to BaOH and the resulting pH

Also the pH of lemon juice and the dilution one.

geiger muller: D (cracks in metals)

HCl to Ba(OH)2: A (0.48 or sum shit cos it was limiting reagent question etc)

pH of lemon juice is worrying me :S i got 77mL cos i did the c1v1 = c2v2 thing then subtracted what i got from idk where since the question asked for the water necessary, not total water

 

[UnrealAnchovies]

Re: CSSA Chemistry 2011

you should.. I think i only made the mistake of not converting metres cubed, so I'm hoping my chem teacher is nice and gives me like 3/4

if i dont get it right, it'll be for the very same reason

 

[Dylanamali]

Re: CSSA Chemistry 2011

geiger muller: D (cracks in metals)

HCl to Ba(OH)2: A (0.48 or sum shit cos it was limiting reagent question etc)

pH of lemon juice is worrying me :S i got 77mL cos i did the c1v1 = c2v2 thing then subtracted what i got from idk where since the question asked for the water necessary, not total water

DAMNIT i did total water =(.. 1 more lost mark there. fml!

 

[Riproot]

I think the equation your referring to is
CO2 (g) <--> CO2 (aq)

You mean H2O + CO2 <--> H2CO3 right?

yup I got the logic behind it now... its cos it dissociates to H+ and HSO4- aye? fahh!!! silly mistakes.

yeah and then that dissociates again but only a little because it's a weak amphiprotic substance.


WHAT WAS THE ELEMENT THAT MADE AN ACID OXIDE?

 

[UnrealAnchovies]

Re: CSSA Chemistry 2011

DAMNIT i did total water =(.. 1 more lost mark there. fml!

its not like im definitely right lol.

 

[Dylanamali]

Re: CSSA Chemistry 2011

Did anyone get tricked by finding the average of the AAS conc. in the MC?

It was SOOO similar to a past HSC question, thank goodness =)

remove the outlier, then find the average, however you can only give it to 3 sig figs as it can't be more accurate than the values that were given.

 

[UnrealAnchovies]

Re: CSSA Chemistry 2011

You mean H2O + CO2 <--> H2CO3 right?

yeah and then that dissociates again but only a little because it's a weak amphiprotic substance.


WHAT WAS THE ELEMENT THAT MADE AN ACID OXIDE?

sulfur dioxide? nitrogen dioxide?

 

[Dylanamali]

Re: CSSA Chemistry 2011

its not like im definitely right lol.

I forgot what the question was.. I thought it was total water not water added, still unsure.

 

[UnrealAnchovies]

Re: CSSA Chemistry 2011

did anyone get tricked by finding the average of the aas conc. In the mc?

It was sooo similar to a past hsc question, thank goodness =)

remove the outlier, then find the average, however you can only give it to 3 sig figs as it can't be more accurate than the values that were given.

yay!

 

[Dylanamali]

Re: CSSA Chemistry 2011

sulfur dioxide? nitrogen dioxide?

+1 i did sulfur.

 

[jamesfirst]

Re: CSSA Chemistry 2011

What mark you reckon you got?

What's it out of ?


I reckon I would get above 85%. But hopefully I come top 3 in the grade.