2009 Chemistry Unit 3 Exam Questions and Suggested Solutions

[avram_grant]

and in theory, couldnt H2 undergo a sub reaction with alkanes; although it wont change the product... still

[Ilovemathsmeth]

I really hope they accept two answers for that q, because hydrogen is flammable so therefore it would not be suitable in GC?

[lacoste]

Mao would have got another 50 in the bag, change the rules VCAA!! And another in 2010 ..etc


It would be cool if you can repeat subjects, but unfair maybe.

[hyperblade01]

Short Answer 3c)

Wouldn't the titre be more as more HCl is required?

[littlecherry25]

what was question 19 in MC?
i don't know what letter i put

but i said that it the percentage increased at you get going higher
shit, now i know its wrong lol

[m.hudson.1990]

for questions 12 in the MC, wouldnt it be 4? 1-chloro-2,2dimethyl butane, 2-chloro-2,2dimethyl butane., 2-chloro-3,3 dimethyl butane and 1-chloro-3,3-dimethyl butane

[avram_grant]

yep, for 3c) short answer, the nHCl will be more so the conc of the other thingy - definitely it the titire is greater

[turley]

to Ilovemathsmeth

lets assume H2 gas is unsuitable since it is flammable.
wouldn't alkanes (more importantly the ones analyise in GC) also be flammable. obviously a conflict

[NE2000]

For Q19 in MC. Just thought I'd add that the Heinemann textbook talks about the lab method for fractional distillation in terms of the concentration of a volatile substance vs. concentration of other substances. According to that book, the ethanol in this case would undergo cycles of evaporation and condensation which would successively increase its concentration. Hence one would imagine that people using this textbook may believe that the concentration of ethanol would not be the same at different heights in the column, rather that the concentration of ethanol just above the mixture is not as high as the concentration in the glass beads, the question now is whether there is significant difference in concentration between the middle of the glass beads and the top of the glass beads?

[NE2000]

for questions 12 in the MC, wouldnt it be 4? 1-chloro-2,2dimethyl butane, 2-chloro-2,2dimethyl butane., 2-chloro-3,3 dimethyl butane and 1-chloro-3,3-dimethyl butane

Just try putting dots next to the carbon where you are adding the chloro. The three left-most carbons are 'equivalent' in a way that adding a chloro to either of these will produce the same compound. So 3 I think is right.

[m.hudson.1990]

yeah, sorry, double checked, three is definitely right.

[kurrymuncher]

Fuck it. Fuck it all

Im ending it tonight

[Ilovemathsmeth]

to Ilovemathsmeth

lets assume H2 gas is unsuitable since it is flammable.
wouldn't alkanes (more importantly the ones analyise in GC) also be flammable. obviously a conflict

damn

what was the concentration effect on sodium hydrogencarbonate - higher as a result of the contaminated HCl?

[avram_grant]

lol, H2 isnt inert! If we cant come to a conclusion through minute of debating, what did they expect us to do in the exam....

[turley]

higher- the concerntration of HCl is less so more is titrated