CSSA chemistry (4 Viewers)

[Dylanamali]

Re: CSSA Chemistry 2011

cos we did this experiment where we got 2 measuring cylinders and filled 1 with water. We then got a pipette to transfer the water into the second cylinder. Then we transfered the water from the 2nd cylinder back into the first one. We repeated this until there was no change in volume.

yeah that was an experiment to model equilibrium - I'm not sure what the eqn is... my school took out the option and replaced it with their own made one, coz we hadn't completed it.

 

[Riproot]

R U SRS! NOOOOOOOO! i could have done that easily FML

Me too!!! I fucking did something we didn't do in class and got it fucking wrong and my friend did it too and got it right so I'm fucked!!!

 

[umz93]

Re: CSSA Chemistry 2011

Lucky! Not only do we have the whole course in our trials we have 2 sets of trials...
What school do you go to?

 

[Dylanamali]

Re: CSSA Chemistry 2011

The only question I'm worried about is the ethanol and octane question. I think I fked up the radioisotope in medicine. I did Tc-99m and said that the problem was the short half life. Hence, it is produced in hospitals. Is this correct ??? lol

The question didn't ask for a specific radioisotope but a problems within a specific industry.. I chose hospitals, and talked about them in general and gave some examples, e.g. technetium and cobalt 60. I talked about the problem being increased exposure to radiation which is a mutagen and thus can lead to cancers and other health problems. I said that this problem could be minimised through the use of new technology. E.g. the short half life of Technetium 99-m to minimise exposure, also the use of cobalt 60 being delievered very accurately using a machine, to minimise its exposure to healthy cells. etc. etc.

 

[Dylanamali]

Re: CSSA Chemistry 2011

Lucky! Not only do we have the whole course in our trials we have 2 sets of trials...
What school do you go to?

rank 300th school

 

[jamesfirst]

Re: CSSA Chemistry 2011

yeah that was an experiment to model equilibrium - I'm not sure what the eqn is... my school took out the option and replaced it with their own made one, coz we hadn't completed it.

our school took about chemical monitoring and replaced it with some more core work question... I finished 30 minutes early. But I got fked with the ethanol + octane question.

How the hell do you even calculate the distance that it'll travel... that was so math and I was braindead.

 

[jamesfirst]

Re: CSSA Chemistry 2011

The question didn't ask for a specific radioisotope but a problems within a specific industry.. I chose hospitals, and talked about them in general and gave some examples, e.g. technetium and cobalt 60. I talked about the problem being increased exposure to radiation which is a mutagen and thus can lead to cancers and other health problems. I said that this problem could be minimised through the use of new technology. E.g. the short half life of Technetium 99-m to minimise exposure, also the use of cobalt 60 being delievered very accurately using a machine, to minimise its exposure to healthy cells. etc. etc.

TBH, I was more prepared to talk about industrial use, but I couldn't spot any significant problems so I just went with medicine. I wanted to challenge myself.

 

[umz93]

Re: CSSA Chemistry 2011

If you give an example from an industry + talk about problems i think you should be fine

 

[Dylanamali]

Re: CSSA Chemistry 2011

our school took about chemical monitoring and replaced it with some more core work question... I finished 30 minutes early. But I got fked with the ethanol + octane question.

How the hell do you even calculate the distance that it'll travel... that was so math and I was braindead.

It was all ratios.. we knew how many kJ's were produced by 1L of octane and that this amount of kJ's corresponded with 10km of driving.

Similarly, we could work out how many mols of ethanol were in 1L of ethanol and then work out how many kJ's were produced. We then used ratios to determine how far that amount of kJ's could drive the car using the values from octane.

 

[Dylanamali]

Re: CSSA Chemistry 2011

TBH, I was more prepared to talk about industrial use, but I couldn't spot any significant problems so I just went with medicine. I wanted to challenge myself.

In my opinion, medicine is easier/safer in terms of identifying problems

 

[jamesfirst]

Re: CSSA Chemistry 2011

It was all ratios.. we knew how many kJ's were produced by 1L of octane and that this amount of kJ's corresponded with 10km of driving.

Similarly, we could work out how many mols of ethanol were in 1L of ethanol and then work out how many kJ's were produced. We then used ratios to determine how far that amount of kJ's could drive the car using the values from octane.

Just couldn't think shit in that question.l oooooooooool

 

[Dylanamali]

Re: CSSA Chemistry 2011

Just couldn't think shit in that question.l oooooooooool

I honestly think the calculations were very tricky and needed a decent knowledge of mathematics.. I think its a bit unfair to those who do general maths or like no maths at all..

 

[jamesfirst]

Re: CSSA Chemistry 2011

I honestly think the calculations were very tricky and needed a decent knowledge of mathematics.. I think its a bit unfair to those who do general maths or like no maths at all..

Oh well. That's good since my rank would be pushed up

 

[Dylanamali]

Re: CSSA Chemistry 2011

Oh well. That's good since my rank would be pushed up

What mark you reckon you got?

 

[Midnight_Lotus]

Re: CSSA Chemistry 2011

Apparently you could talk about decarbonating soft drinks. But I did this weird experiment in school.


Does this equation make sense:


H2O <-> H2O ?

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

 

[_deloso]

Re: CSSA Chemistry 2011

l

that's wrong. Sulphuric acid only partially dissociates the second h+ ion.

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

 

[Dylanamali]

Re: CSSA Chemistry 2011

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

so whats the answer????

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

 

[umz93]

Re: CSSA Chemistry 2011

What was the answer to the last part of titration question, why did he use solid? i didnt know that at all!

 

[UnrealAnchovies]

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

 

[UnrealAnchovies]

Re: CSSA Chemistry 2011

What was the answer to the last part of titration question, why did he use solid? i didnt know that at all!

naoh draws in water from its surroundings (hygroscopic)