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VCE Stuff => VCE Science => VCE Mathematics/Science/Technology => VCE Subjects + Help => VCE Chemistry => Topic started by: vce01 on November 10, 2008, 05:08:26 pm

Title: what should i study?
Post by: vce01 on November 10, 2008, 05:08:26 pm: for the first time in about 4 months im going to be spending some time on chem, the day before the exam

what do you guys reckon i should go through? so that i can somehow pull a D ;P obviously the questions that are most likely to be asked

1. equlibrium
2. ..?

thanks
Title: Re: what should i study?
Post by: Pandemonium on November 10, 2008, 05:16:34 pm: 2. calorimetry
3. galvanic/electrolytic
4. acid/base equilibria
5. AWRHAOWIRHeiowhf3092qu 3r921dnh0pwafaw waeA
Title: Re: what should i study?
Post by: lanvins on November 10, 2008, 05:18:20 pm: yea i'm kind of in the same situation, but i'm not as bad, it's been like a month since i've done any chem.
Title: Re: what should i study?
Post by: Collin Li on November 10, 2008, 05:18:43 pm: Quote from: Pandemonium on November 10, 2008, 05:16:34 pm
5. AWRHAOWIRHeiowhf3092qu 3r921dnh0pwafaw waeA

Agreed
Title: Re: what should i study?
Post by: Survivor on November 10, 2008, 05:20:19 pm: 2 months for me.

LOL 25, here I come.
Title: Re: what should i study?
Post by: bucket on November 10, 2008, 11:40:27 pm: I haven't done chem in like a month =_=...I think I'll be alright though as I have done all my homework and it's just a matter of revising. But yeah, one thing I don't understand, how do you determine which chemicals in an electrolysis cell are going to react? :S I always get fucked up with that, is there a trick to it? :S Or better yet, a proper way to work it out other than guessing? :P
Title: Re: what should i study?
Post by: bec on November 11, 2008, 08:03:15 am: Quote from: bucket on November 10, 2008, 11:40:27 pm
one thing I don't understand, how do you determine which chemicals in an electrolysis cell are going to react? :S I always get fucked up with that, is there a trick to it? :S Or better yet, a proper way to work it out other than guessing? :P

Highlight/circle everything that's there. So if you've got $CaCl_2(aq)$ and $MgBr_2(aq)$ you need to circle Ca2+, Cl-, Br-, Mg2+ and H2O then you need to just choose the top one on the left side (= best oxidant) and the bottom one on the right side (best reductant).

In this case:
- Best oxidant is water ( $2H_2O + 2e^- \rightarrow H_2 + 2 OH^-$ )
- Best reductant is calcium ( $Ca \rightarrow Ca^{2+} + 2e^-$ )

...so yes, there is way to work it out other than guessing...
Title: Re: what should i study?
Post by: bucket on November 11, 2008, 08:31:31 am: But isn't the chemical on the left side supposed to be positioned LOWER than the one it is reacting with on the right side, like in a / direction on the electrochemical series? Furthermore, I do all that but the problem I face is WHICH pair of chemicals to use; there is often a number of chemicals that seem to be ideal to react. I used to assume that calculating which chemicals have a smaller E^o difference would help but it doesn't always seem to work. :S
If it's still not clear what my problem is I'll post an example up later on today when I finally force myself to hit the books :S.
Title: Re: what should i study?
Post by: gabrielle__ on November 11, 2008, 08:36:17 am: Quote from: bucket on November 11, 2008, 08:31:31 am
But isn't the chemical on the left side supposed to be positioned LOWER than the one it is reacting with on the right side, like in a / direction on the electrochemical series? Furthermore, I do all that but the problem I face is WHICH pair of chemicals to use; there is often a number of chemicals that seem to be ideal to react. I used to assume that calculating which chemicals have a smaller E^o difference would help but it doesn't always seem to work. :S
If it's still not clear what my problem is I'll post an example up later on today when I finally force myself to hit the books :S.

bucket im pretty sure that it goes in a \ direction.
right hand lower than left, but good luck for thursday :P
Title: Re: what should i study?
Post by: bucket on November 11, 2008, 08:38:01 am: Nooooo! They go that way (\) in galvanic cells!
I'm asking about electrolytic reactions which go in the / direction.
Silly ;)
Title: Re: what should i study?
Post by: gabrielle__ on November 11, 2008, 08:41:12 am: oh whoops
should probably read the whole thread before talking then hay!
fuccking wankwit i am ! :P
Title: Re: what should i study?
Post by: Collin Li on November 11, 2008, 10:48:09 am: Haha, you two have black and white avatars I feel like I'm in the 50s.