Post by: Mao on June 09, 2010, 05:25:28 pm
Note, this is an unofficial release, to be used as a guide for how you performed, not the actual marking scheme. Released as a VN community resource.
MCQ
Question 1 - C
Question 2 - D
Question 3 - A
Question 4 - C
Question 5 - C
Question 6 - A
Question 7 - A
Question 8 - B
Question 9 - B [Note, this is at the VCE level though, but determining the concentration of red dye at 500nm has a fairly large amount of uncertainty involved. In actual practice, I'd expect the chemist to run the test at 640nm first [red dye neglegible, blue dye near max absorption] to determine the concentration of the blue dye, then make up the standards containing the determined concentration of blue dye and varying concentration of red dye.]
Question 10 - C
Question 11 - A [The only isomer is 1,1,2-trichloroethene]
Question 12 - D
Question 13 - B [Note, congratulations to VCAA for applying some decent chemistry, option D gives the correct isomer]
Question 14 - D
Question 15 - B [Note, imagine as a cyclic chain = 51 peptides, take away two peptides to make two strands yields 49]
Question 16 - C
Question 17 - D
Question 18 - B
Question 19 - C
Question 20 - B
Short Answer
Question 1
a.
b.
c.
d.
e.
Question 2
a. C=O, carbonyl group [NOT carboxyl, ketone or aldehyde]
b. 3
c. 3
d.i. 2
d.ii.
Code: [Select]
H H
| |
-C-C-H
| |
H H
e. ethyl methanoate HCOOCH2CH[/sub]3[/sub]Code: [Select]
H
|
O=C H H
| | |
O-C-C-H
| |
H H
Question 3
a.
b. A. Impossible to have peaks at 45, 31, 29, 27, etc
c. NO+ [Note: the positive charge is essential]
Question 4
a. A, D [Note: quite sure about D, technically the O- will react, and P=O will be of an equivalent state as the O-, so if anything is going to react, it won't be the OH. But I have no idea how much VCAA would simplify organic chemistry, they may be targeting the point that a phosphoester bond is formed, thus you need an OH group.]
b.i. Hydrogen bonding
b.ii. C, F
Question 5
a.i. Different volatile chemicals separate in the chromatograph, and produce distinct peaks. The peak corresponding to ethanol is separate from other volatile chemicals, and the measurement of this peak size will give a relative amount of ethanol.
a.ii. The peak at 0.9 minutes corresponds to ethanol.
b. 0.22% m/v
Question 6
a. An enzyme's function is an effect of its structure. Its structure is usually optimized for binding to a particular substrate in a particular manner, thus only catalysing one particular reaction specific to this structure.
b. 55oC, pH 5
c. Changing the pH can affect the tertiary structure (particularly ionic attractions between acidic and alkaline groups), affecting its structure and thus its activity.
d.
Question 7
a.i. 3
a.ii.
b.i.
b.ii. C22H32O2
Question 8
a. Ether
b.i. Carbohydrates, specifically a hexose monosaccharide.
b.ii. -OH
c.i. Oxidation
c.ii. Acidified Permanganate (H+/MnO4-) or Acidified Dichromate (H+/Cr2O72-)
d. Ethanoic Acid or Acetic Anhydride, both are possible [Note, sulfuric acid is used as catalyst for both mechanisms]
e. The carboxyl group up the top loses H+, becomes COO-, otherwise the structure is the same. [tex]C_6H_4(COO^-)(OOCCH_3)[Note: cbf drawing]
Question 9
a.i. Methanol or Ethanol
a.ii. Since the first fraction is collected at 97.2 degrees, this must be the lightest alkanol. Methanol/Ethanol boil before this temperature, thus if they were present, the first fraction would be collected at 64.5/78.3 degrees.
b. Alkanols are volatile and combustible. Alkanol vapours are in fact explosive. Using a naked flame (bunsen burner) is a serious hazard in dealing with these chemicals.
c. Propan-1-ol is overall polar, and the presence of OH also allows for hydrogen bonding to occur, the intermolecular attractions (dipole-dipole and H-bonding) is strong, thus it will have a high boiling point. Butane is overall non-polar, and the only intermolecular attraction is dispersion forces (weak), thus it will have a low boiling point. The difference between the strength of intermolecular forces is very large, polar forces are much stronger than dispersion forces, thus explaining the very large difference (~240K) between the BP of the two chemicals.
Post by: 10weid on June 09, 2010, 05:27:47 pm
othawise this seems right:)
Post by: tcg93 on June 09, 2010, 05:28:20 pm
Post by: Stroodle on June 09, 2010, 05:28:23 pm
Oh, and can you sticky this thread?
Post by: Ilovemathsmeth on June 09, 2010, 05:33:03 pm
Post by: scocliffe09 on June 09, 2010, 05:33:26 pm
Pretty sure Q4 is C
I agree - 4C
Post by: stonecold on June 09, 2010, 05:34:12 pm
Post by: scocliffe09 on June 09, 2010, 05:36:20 pm
VCE Chemistry 2010 Unit 3 Exam Suggested Solutions
Note, this is an unofficial release, to be used as a guide for how you performed, not the actual marking scheme. Released as a VN community resource.
MCQ
Question 1 - C
Question 2 - D
Question 3 - A
Question 4 - B
Question 5 - C
Question 6 - A
Question 7 - A
Question 8 - B
Question 9 - B [Note, this is at the VCE level though, but determining the concentration of red dye at 500nm has a fairly large amount of uncertainty involved. In actual practice, I'd expect the chemist to run the test at 640nm first [red dye neglegible, blue dye near max absorption] to determine the concentration of the blue dye, then make up the standards containing the determined concentration of blue dye and varying concentration of red dye.]
Question 10 - C
Question 11 - A [The only isomer is 1,1,2-trichloroethene]
Question 12 - D
Question 13 - B [Note, congratulations to VCAA for applying some decent chemistry, option D gives the correct isomer] -
a bit of markovnikov's rule never hurt anyone!
Post by: jimmy999 on June 09, 2010, 05:41:52 pm
I must say the way they asked some questions is unique, however the NMR/IR spec question was kind of too easy. It set everything out easily so it was almost impossible to answer it wrong. In my opinion, those not completely comfortable with chemistry would've struggled to finish it in time
Post by: Mao on June 09, 2010, 05:42:20 pm
And yes, Markovnikov.
Post by: Blakhitman on June 09, 2010, 05:42:40 pm
Post by: Blakhitman on June 09, 2010, 05:43:58 pm
Post by: Mao on June 09, 2010, 05:44:58 pm
Post by: TrueTears on June 09, 2010, 05:45:09 pm
Sticked.
Post by: taiga on June 09, 2010, 05:45:57 pm
22.03 is within 0.05 of another titre which is concordant, hence it too is concordant.
Post by: Blakhitman on June 09, 2010, 05:46:53 pm
Post by: superflya on June 09, 2010, 05:47:03 pm
What I don't get is how 22.03 is concordant with the others?
it was the 2nd titre that wasnt concordant.
but it's 0.06 away from the other. Don't they ALL have to be within 0.05??
Post by: 10weid on June 09, 2010, 05:47:08 pm
% mass at end of Q1 is 3.81%, it is 3.07/80.50=3.8136....
and im fairly certain u didnt have to specify the carbonyl gorup, merely had to say the atoms and the bond type, so had to say C=O results in absorption band at 1750cm-1....
Post by: jimmy999 on June 09, 2010, 05:48:37 pm
And yes, the style of this exam is very different to other past exams. I think this year a few academics at Monash helped out in writing the exam, the style is very similar to Prof. Morrison's exams. [Incidentally, he's an assessor this year, and also incidentally, he made the chemical detectives program. Go him.]
Yes I did have Richard and he did say he was writing this years exam. Hopefully he writes my exam in a way like this
Post by: Blakhitman on June 09, 2010, 05:52:25 pm
What I don't get is how 22.03 is concordant with the others?
it was the 2nd titre that wasnt concordant.but it's 0.06 away from the other. Don't they ALL have to be within 0.05??
serious?? I always thought is was 0.05???
Post by: zzzzzz on June 09, 2010, 05:54:05 pm
Post by: akira88 on June 09, 2010, 05:54:43 pm
but it's 0.06 away from the other. Don't they ALL have to be within 0.05??THATS WHAT I THOUGHT.
Because if they're 0.05 from each other, eg. you could have this as concordant:
22.05, 22.10, 22.15,22.20 etc, but yet 22.05 and 22.20 are .15 off :S
and I thought it was 0.05, not 0.1 off :S
I think different textbooks say different things >.<
Post by: clumsy_culhane on June 09, 2010, 05:55:45 pm
Post by: VeryCrazyEdu. on June 09, 2010, 05:56:21 pm
EDIT: wwoooooooppss i meant .1 overall haha not .01 :P
Post by: andy456 on June 09, 2010, 05:56:41 pm
Post by: superflya on June 09, 2010, 05:56:49 pm
Post by: crayolé on June 09, 2010, 05:57:37 pm
Mao can you explain your reasoning behind your answer of 2 for the question: "The signal at 1.3 ppm is split into a triplet. What is the number of equivalent protons bonded to the adjacent carbon atom?" (Page 13)n+1 rule
3 peaks means it's got two adjacent hydrogens
Post by: clumsy_culhane on June 09, 2010, 06:01:33 pm
Mao can you explain your reasoning behind your answer of 2 for the question: "The signal at 1.3 ppm is split into a triplet. What is the number of equivalent protons bonded to the adjacent carbon atom?" (Page 13)n+1 rule
3 peaks means it's got two adjacent hydrogens
But to form splits in the peaks, the hydrogens have to be in different environments , i.e. in non-equivalent environments. Which means there are zero protons bonded to the adjacent carbon that are equivalent.
From KBT solutions :"If the hydrogens of a particular environment have n neighbouring, non-equivalent hydrogens,
the peak from that environment will be split into n+1 component peaks.
Keep in mind that the word ‘neighbouring’ as it’s used above means ‘on the adjacent carbon
atom’. ‘Non-equivalent’ means ‘not of the same environment’."
(http://www.kbtlectures.com/wp-content/uploads/2010/04/KBT_unit3chemistry_trialexamsolutions.pdf)
Post by: jimmy999 on June 09, 2010, 06:06:41 pm
okies..MAO:If you bring the exact values through on the calculator, you end up with 3.82% which is the actual correct answer. However if you use sig figs through the question you get 3.81%. Hence I think they will allow both answers
% mass at end of Q1 is 3.81%, it is 3.07/80.50=3.8136....
Post by: VeryCrazyEdu. on June 09, 2010, 06:07:35 pm
okies..MAO:If you bring the exact values through on the calculator, you end up with 3.82% which is the actual correct answer. However if you use sig figs through the question you get 3.81%. Hence I think they will allow both answers
% mass at end of Q1 is 3.81%, it is 3.07/80.50=3.8136....
yeah...they have allowed both answers in previous exams...
Post by: Studyinghard on June 09, 2010, 06:09:22 pm
Post by: 10weid on June 09, 2010, 06:09:46 pm
also, did u hav to specify ethanoic anhyride or was ethanoic acid suffieicent?
coz their is no arguing that additon of ehtanoic acid to the pervious compound woul dresult in the one required :s
???
Post by: taiga on June 09, 2010, 06:10:06 pm
I guess it's up to the assessors.
Post by: Streaker on June 09, 2010, 06:12:29 pm
Post by: 10weid on June 09, 2010, 06:13:10 pm
You're supposed to use as many decimal places as you can during the working out though aren't you?. I wouldn't be surprised if they slashed half a mark for 3.81
I guess it's up to the assessors.
no, because the previous value (3.07 grams) is to the correct number of significant figures..
so any subsequent calculations technically have to use 3,81 as a value, as it the most accurate than can be carried thoguh from previous calculations..
Post by: 10weid on June 09, 2010, 06:13:34 pm
so any subsequent calculations technically have to use 3,81 as a value, as it the most accurate than can be carried thoguh from previous calculations..
Post by: taiga on June 09, 2010, 06:15:45 pm
Post by: Studyinghard on June 09, 2010, 06:17:09 pm
you didnt include the Iodine in it.
Post by: Richiie on June 09, 2010, 06:18:53 pm
Post by: 98.40_for_sure on June 09, 2010, 06:19:51 pm
Post by: 10weid on June 09, 2010, 06:20:06 pm
The answer for 7bii is wrong.
you didnt include the Iodine in it.
ur not meant to.
the iodine was used to work out how many double bonds..however u dont need to include it in the formula of te organic compound..
Post by: Blakhitman on June 09, 2010, 06:20:21 pm
The answer for 7bii is wrong.
you didnt include the Iodine in it.
lolwut, it asked for cervaic acid, which Iodine reacts WITH.
Post by: Studyinghard on June 09, 2010, 06:21:24 pm
Post by: bomb on June 09, 2010, 06:21:46 pm
The answer for 7bii is wrong.
you didnt include the Iodine in it.
Nah, the question asked for the formula of the acid, not of the product.
But, 7bi is wrong, because you didn't count the C=O, it asked for ALL double bonds.
Post by: andy456 on June 09, 2010, 06:21:57 pm
Post by: VeryCrazyEdu. on June 09, 2010, 06:22:06 pm
Post by: 10weid on June 09, 2010, 06:22:09 pm
the temp of maximal enzymic activity is deifinitely 55 degrees.
and 1.5 litres is the answee to the volume of methanol
and i'm 99% sure u didnt need to include states in the mass spec quesiton.. for one mark merely showing the loss of an electron was adequate....
agree? :)
Post by: curious111 on June 09, 2010, 06:22:16 pm
Post by: vexx on June 09, 2010, 06:22:50 pm
and people it's definitely 35 degrees for that question since it has the highest reaction there, annnnnnd i was quite sure states were needed and stated at the start of the exam. it should be known that in mass spec everything is vaporised before ionisation.
Post by: Blakhitman on June 09, 2010, 06:23:41 pm
But, 7bi is wrong, because you didn't count the C=O, it asked for ALL double bonds.
I reckon that's just silly, be retarded if we had to say 7, seriously aren't they just testing our ability to determine saturation?
Post by: stonecold on June 09, 2010, 06:24:14 pm
Post by: Blakhitman on June 09, 2010, 06:25:01 pm
we were taught that concordant titres must lie within 0.02ml of each other, and if there is only two that do, then just use those two and justify "+/- 0.02ml". if this isn't right, then i'll be so upset.. hah
and people it's definitely 35 degrees for that question since it has the highest reaction there, annnnnnd i was quite sure states were needed and stated at the start of the exam. it should be known that in mass spec everything is vaporised before ionisation.
That's what I did!
Post by: Twenty10 on June 09, 2010, 06:25:38 pm
we were taught that concordant titres must lie within 0.02ml of each other, and if there is only two that do, then just use those two and justify "+/- 0.02ml". if this isn't right, then i'll be so upset.. hahsame...
and people it's definitely 35 degrees for that question since it has the highest reaction there, annnnnnd i was quite sure states were needed and stated at the start of the exam. it should be known that in mass spec everything is vaporised before ionisation.
That's what I did!
Post by: Studyinghard on June 09, 2010, 06:25:50 pm
Post by: stonecold on June 09, 2010, 06:26:21 pm
Post by: Studyinghard on June 09, 2010, 06:26:55 pm
Post by: will74 on June 09, 2010, 06:28:30 pm
Post by: stonecold on June 09, 2010, 06:28:51 pm
Post by: vexx on June 09, 2010, 06:29:02 pm
we were taught that concordant titres must lie within 0.02ml of each other, and if there is only two that do, then just use those two and justify "+/- 0.02ml". if this isn't right, then i'll be so upset.. hahsame...
and people it's definitely 35 degrees for that question since it has the highest reaction there, annnnnnd i was quite sure states were needed and stated at the start of the exam. it should be known that in mass spec everything is vaporised before ionisation.
That's what I did!
awesome. i reckon we'll get the mark.
Post by: crayolé on June 09, 2010, 06:29:20 pm
It asked for the ration so it should be right hopefully
And the enzyme, isnt it's optimal temperature 55 degrees ?
Post by: vexx on June 09, 2010, 06:29:56 pm
im pretty sure the invertase question was optimum at 55 degrees. And i've looked up invertase and its optimum temp is around 60 degrees and its optimum pH around 4.5??
this is vce land, we don't require outside knowledge (from our vce course ;] )
the optimum temp according to that graph was 35, look at it againnn.
Post by: will74 on June 09, 2010, 06:30:16 pm
Post by: Studyinghard on June 09, 2010, 06:30:36 pm
im pretty sure the invertase question was optimum at 55 degrees. And i've looked up invertase and its optimum temp is around 60 degrees and its optimum pH around 4.5??
this is vce land, we don't require outside knowledge (from our vce course ;] )
the optimum temp according to that graph was 35, look at it againnn.
dude look at the key of the graph. its a bit tricky. its 55!
Post by: 10weid on June 09, 2010, 06:31:28 pm
Post by: Stroodle on June 09, 2010, 06:31:42 pm
Post by: will74 on June 09, 2010, 06:31:47 pm
Post by: stonecold on June 09, 2010, 06:32:24 pm
triangles = 55 degrees.
Post by: vexx on June 09, 2010, 06:32:29 pm
im pretty sure the invertase question was optimum at 55 degrees. And i've looked up invertase and its optimum temp is around 60 degrees and its optimum pH around 4.5??
this is vce land, we don't require outside knowledge (from our vce course ;] )
the optimum temp according to that graph was 35, look at it againnn.
dude look at the key of the graph. its a bit tricky. its 55!
oh sorry haha yeah it is 55, i just looked at it again, my memory isn't my friend right now >_>
Post by: jake on June 09, 2010, 06:32:39 pm
we were taught that concordant titres must lie within 0.02ml of each other, and if there is only two that do, then just use those two and justify "+/- 0.02ml". if this isn't right, then i'll be so upset.. hahsame...
and people it's definitely 35 degrees for that question since it has the highest reaction there, annnnnnd i was quite sure states were needed and stated at the start of the exam. it should be known that in mass spec everything is vaporised before ionisation.
That's what I did!
99% sure its 55 degrees. look carefully the key for 35 degrees is diamond in shape and the key for 55 degrees is triangular. the graph at the top (most activity) has triangles NOT diamonds and is hence 55 degrees not 35. sorry guys
Post by: will74 on June 09, 2010, 06:33:13 pm
CH3CH2OH + e- >>>> CH3CH2OH+ + 2e-
including the bombarding electron?
Post by: vexx on June 09, 2010, 06:33:38 pm
will: that is correct, it is what the books says.
Post by: Blakhitman on June 09, 2010, 06:33:45 pm
we were taught that concordant titres must lie within 0.02ml of each other, and if there is only two that do, then just use those two and justify "+/- 0.02ml". if this isn't right, then i'll be so upset.. hahsame...
and people it's definitely 35 degrees for that question since it has the highest reaction there, annnnnnd i was quite sure states were needed and stated at the start of the exam. it should be known that in mass spec everything is vaporised before ionisation.
That's what I did!
99% sure its 55 degrees. look carefully the key for 35 degrees is diamond in shape and the key for 55 degrees is triangular. the graph at the top (most activity) has triangles NOT diamonds and is hence 55 degrees not 35. sorry guys
I was talking about the concordant titre lol.
Post by: crayolé on June 09, 2010, 06:34:06 pm
Post by: kenhung123 on June 09, 2010, 06:34:21 pm
Post by: will74 on June 09, 2010, 06:34:38 pm
sorry again, i should really have double checked the paper before i assumed that mao had read it right xD
will: that is correct, it is what the books says.
cheers :)
Post by: kenhung123 on June 09, 2010, 06:35:00 pm
hey is this wrong for mass specaccording to heinemann yes that is correct.
CH3CH2OH + e- >>>> CH3CH2OH+ + 2e-
including the bombarding electron?
Post by: 10weid on June 09, 2010, 06:35:07 pm
Post by: stonecold on June 09, 2010, 06:35:15 pm
hey is this wrong for mass spec
CH3CH2OH + e- >>>> CH3CH2OH+ + 2e-
including the bombarding electron?
nahh that's right. not sure if you needed to put (g). I just included it.....
Post by: vexx on June 09, 2010, 06:35:36 pm
You didnt do 35 in the exam did you vexx? :/don't think so..
haha i'm so stressed now ! ai;dawk;dkaw;ldkaw;dlk'wa
what if i did :| im sure i didnt though..
Post by: bomb on June 09, 2010, 06:35:52 pm
But, 7bi is wrong, because you didn't count the C=O, it asked for ALL double bonds.
I reckon that's just silly, be retarded if we had to say 7, seriously aren't they just testing our ability to determine saturation?
Pretty much. I think it's silly too, but I'm just saying.
Post by: Studyinghard on June 09, 2010, 06:36:05 pm
Post by: 10weid on June 09, 2010, 06:36:09 pm
we were taught that concordant titres must lie within 0.02ml of each other, and if there is only two that do, then just use those two and justify "+/- 0.02ml". if this isn't right, then i'll be so upset.. hahsame...
and people it's definitely 35 degrees for that question since it has the highest reaction there, annnnnnd i was quite sure states were needed and stated at the start of the exam. it should be known that in mass spec everything is vaporised before ionisation.
That's what I did!
99% sure its 55 degrees. look carefully the key for 35 degrees is diamond in shape and the key for 55 degrees is triangular. the graph at the top (most activity) has triangles NOT diamonds and is hence 55 degrees not 35. sorry guys
JAKE!
do i know u?
Post by: 10weid on June 09, 2010, 06:36:33 pm
Post by: andy456 on June 09, 2010, 06:36:43 pm
i reckin frorula means molcular formaula as ooppposed to semi-structural formula..It doesnt say that in the exam so both should be accepted
Post by: VeryCrazyEdu. on June 09, 2010, 06:37:56 pm
Post by: crayolé on June 09, 2010, 06:38:29 pm
Post by: kenhung123 on June 09, 2010, 06:39:24 pm
Post by: Blakhitman on June 09, 2010, 06:40:12 pm
Post by: andy456 on June 09, 2010, 06:41:01 pm
Post by: cochra on June 09, 2010, 06:42:19 pm
Post by: curious111 on June 09, 2010, 06:42:28 pm
Post by: jake on June 09, 2010, 06:43:25 pm
we were taught that concordant titres must lie within 0.02ml of each other, and if there is only two that do, then just use those two and justify "+/- 0.02ml". if this isn't right, then i'll be so upset.. hahsame...
and people it's definitely 35 degrees for that question since it has the highest reaction there, annnnnnd i was quite sure states were needed and stated at the start of the exam. it should be known that in mass spec everything is vaporised before ionisation.
That's what I did!
99% sure its 55 degrees. look carefully the key for 35 degrees is diamond in shape and the key for 55 degrees is triangular. the graph at the top (most activity) has triangles NOT diamonds and is hence 55 degrees not 35. sorry guys
JAKE!
do i know u?
DUDE! good job btw 50 already for you mister 99.95
Post by: Mao on June 09, 2010, 06:44:28 pm
I think the solutions are right now. Cheers to bomb for pointing out there is a C=O double bond, though I REALLY doubt VCAA would be that anal.
So big cheers to andrewloppol who made this possible. Hope you all went well. :)
Oh, and I am not predicting a grade range, I'm too out of touch with VCE at the moment to be able to make that kind of predictions. A couple years ago, maybe. But I have to say, the exam wasn't difficult, and it wasn't that tricky either. So yeah, the A+ cut off would be higher than last year.
Post by: will74 on June 09, 2010, 06:44:53 pm
Wasn't question 9.a asking about the alkanols in the mixture collected once it had been distilled?
omg that is what i thought! in the fraction....but i don't know if they will take into consideration how incredibly vague the question was!
Post by: Stroodle on June 09, 2010, 06:45:22 pm
Think I'll still get the mark?
Post by: crayolé on June 09, 2010, 06:45:53 pm
Will probably be like that methods exam a couple years back where the examiners marked fucking hard as since it was so 'easy'.
Judging by the reactions in from my class, there'll be a few <50% scores to bring your averages up c:
Post by: stonecold on June 09, 2010, 06:46:23 pm
And also, was Ethanoic Acid acceptable in Question 8?
Post by: Blakhitman on June 09, 2010, 06:46:52 pm
Yep, that'll teach me for not reading the graph properly. In fact, I'll blame it on andrewloppol for his crap scanning [jks man, great job, my own stupidity for not thinking it through]
I think the solutions are right now. Cheers to bomb for pointing out there is a C=O double bond, though I REALLY doubt VCAA would be that anal.
So big cheers to andrewloppol who made this possible. Hope you all went well. :)
Oh, and I am not predicting a grade range, I'm too out of touch with VCE at the moment to be able to make that kind of predictions. A couple years ago, maybe. But I have to say, the exam wasn't difficult, and it wasn't that tricky either. So yeah, the A+ cut off would be higher than last year.
Legend beyond comprehension.
Post by: andy456 on June 09, 2010, 06:47:07 pm
Post by: Mao on June 09, 2010, 06:47:17 pm
Wait..is Ethanoic Acid an acceptable answer for 8d?
Yes, oops, I was meant to say ethanoic acid instead of ethanol.
As for Q9.a, it is specifically talking about the initial mixture (pure liquids from distillation are called 'fractions').
Post by: will74 on June 09, 2010, 06:48:14 pm
Could you say not to use a bunsen burner as you have no control over the termperature Mao?
And also, was Ethanoic Acid acceptable in Question 8?
i got ethanoic acid...i think that's right....the OH becomes ester+CH3 which needs ethanoic acid and yields water
Post by: VeryCrazyEdu. on June 09, 2010, 06:48:27 pm
Post by: 98.40_for_sure on June 09, 2010, 06:50:32 pm
as the fractionating column gets cooler as it goes up
so doesnt it make sense that if they were in it, they would be collected first? as they condense first
there is no diagram specifying how the equipment is set up like in 2009 exam MC q19(around there?)
Post by: kenhung123 on June 09, 2010, 06:50:55 pm
Post by: Studyinghard on June 09, 2010, 06:50:58 pm
the bunsen burner varies in temperature therefore it is hard to keep a constant temperature and have a good separation of mixtures.
Post by: kenhung123 on June 09, 2010, 06:51:39 pm
Damn. I just wrote MnO4- without the H+ :(
Think I'll still get the mark?
Post by: Blakhitman on June 09, 2010, 06:53:02 pm
hmm for question 9, why cant it be the larger alcohols that isnt possible in it
as the fractionating column gets cooler as it goes up
so doesnt it make sense that if they were in it, they would be collected first? as they condense first
there is no diagram specifying how the equipment is set up like in 2009 exam MC q19(around there?)
They turn to gases last, so they would be collected last, methanol would be collected first and it would be at 60 something, but the first was at 97.2? so hence methanol (or ethanol) cannot be in the mixture.
Post by: vexx on June 09, 2010, 06:54:46 pm
Could you say the one with high boiling point for 9a? Saying its not hot enough to heat vapourise
they are asking what couldn't be in the mixture
and the mixture has it's first componant (out of the two) come out at 97.2, and so if the first of them is that high, the other could be either of the other higher boiling points but it cannot be the lower ones.
Post by: kakar0t on June 09, 2010, 06:56:47 pm
Post by: 98.40_for_sure on June 09, 2010, 06:58:16 pm
and as they go up, the temperature drops
so the highest boiling point would condense and be collected first?
ahh so confused
Post by: vexx on June 09, 2010, 06:59:26 pm
But isn't this lab fractional distillation like the one in heinemann book? So the lighter fractions are collected before the ones in the bottom?
yeah the lighter ones are collected first, so if it was heated to 97.2 then the lighter ones would be out of the mixture due to high temps, therefore since it is asking what can't be in the mixture it has to be the lighter ones, since it says the first component is at 97.2
this question was so stupid, it was merely an interpretation question
Post by: stonecold on June 09, 2010, 07:02:53 pm
Can an answer for 9b have
the bunsen burner varies in temperature therefore it is hard to keep a constant temperature and have a good separation of mixtures.
I'm praying yes...
Post by: kenhung123 on June 09, 2010, 07:03:08 pm
Post by: Studyinghard on June 09, 2010, 07:03:58 pm
Post by: stonecold on June 09, 2010, 07:04:20 pm
Post by: andy456 on June 09, 2010, 07:06:20 pm
Post by: Studyinghard on June 09, 2010, 07:07:18 pm
Maybe heaps of people in the state wrote the higher ones and they will give sympathy marks for misinterpreting the question.....(I hope)
Thats what I hope for the questions I mis-read aswell ;). never happens unfortunately.
Post by: andy456 on June 09, 2010, 07:08:11 pm
Post by: stonecold on June 09, 2010, 07:08:39 pm
They did it on purpose.
Post by: vexx on June 09, 2010, 07:09:19 pm
Maybe heaps of people in the state wrote the higher ones and they will give sympathy marks for misinterpreting the question.....(I hope)
Thats what I hope for the questions I mis-read aswell ;). never happens unfortunately.
yeah never happens, past exams have had
"many students interpretted this question" and it's like 90% 0 getting it.
it happens all the time, it'll be fine since it'll just lower the cutoffs by a mark or whatever (even though im sure more then 10% got it correct haha)
Post by: Studyinghard on June 09, 2010, 07:11:14 pm
Maybe heaps of people in the state wrote the higher ones and they will give sympathy marks for misinterpreting the question.....(I hope)
Thats what I hope for the questions I mis-read aswell ;). never happens unfortunately.
yeah never happens, past exams have had
"many students interpretted this question" and it's like 90% 0 getting it.
it happens all the time, it'll be fine since it'll just lower the cutoffs by a mark or whatever (even though im sure more then 10% got it correct haha)
This for the double bonds question. 7 double bonds im starting to think aswell. But its just stupid tbh. however thats how the cookie crumbles?
Post by: samuch on June 09, 2010, 07:12:49 pm
Post by: Richiie on June 09, 2010, 07:13:04 pm
Post by: Mao on June 09, 2010, 07:14:22 pm
Could you say not to use a bunsen burner as you have no control over the termperature Mao?
No, the temperature can be easily controlled by using adjusting the flame while looking at a thermometer.
Post by: vexx on June 09, 2010, 07:15:06 pm
Post by: Akirus on June 09, 2010, 07:16:33 pm
it appears my motivation to study more this semester has elevated by so much, i am determined to do so much better at the end of year for the exam! so DONT WORRY everyone, we have 50% of our score to go, there's so much room for improvement.
At the moment, my motivation is hanging in the balance depending on the A+ cut-offs. >.>
Post by: 98.40_for_sure on June 09, 2010, 07:19:11 pm
stupid misinterpretations cost me like 10 marks at least
Post by: Blakhitman on June 09, 2010, 07:19:39 pm
Could you say not to use a bunsen burner as you have no control over the termperature Mao?
No, the temperature can be easily controlled by using adjusting the flame while looking at a thermometer.
Never knew you could change the temp...damn!
I saw "mixture is GENTLY heated" and thought, ahh can't do that with bunsen, thought I was clever lol.
Post by: Studyinghard on June 09, 2010, 07:20:15 pm
Could you say not to use a bunsen burner as you have no control over the termperature Mao?
No, the temperature can be easily controlled by using adjusting the flame while looking at a thermometer.
but it changes constantly doesnt it? you cant exactly "control" the flame.
Post by: rubiks on June 09, 2010, 07:22:52 pm
Post by: stonecold on June 09, 2010, 07:23:04 pm
I also pray that a bug crawls into my paper and takes a shit on page 21, right in between the 1 and the 5 so it looks like there is a decimal point and reads 1.5 L haha...
:P
Post by: kenhung123 on June 09, 2010, 07:23:11 pm
Post by: Studyinghard on June 09, 2010, 07:24:46 pm
Post by: rubiks on June 09, 2010, 07:26:03 pm
Is there any chance of getting a decent study score with a B+ in this exam?
Post by: Russ on June 09, 2010, 07:28:15 pm
1 probably
Is there any chance of getting a decent study score with a B+ in this exam?
Depends what you define "decent" as
Post by: chansthename on June 09, 2010, 07:30:26 pm
Meh, atm I concede 2 marks. I'm just praying that I filled out the MC answer sheet right.
I also pray that a bug crawls into my paper and takes a shit on page 21, right in between the 1 and the 5 so it looks like there is a decimal point and reads 1.5 L haha...
:P
Same, 2 marks from multi but there is a short answer that I am sceptical of, just hope I did the right thing, still at worst on that specific question 1 mark.
Post by: Blakhitman on June 09, 2010, 07:30:42 pm
Post by: Russ on June 09, 2010, 07:32:46 pm
Quote
35/36?
Haven't been around the VCE system for a while now, but with a very strong end of year mark you could do it. (that's only my opinion though, someone else more familiar could give a better estimate)
Post by: rubiks on June 09, 2010, 07:34:55 pm
Haven't been around the VCE system for a while now, but with a very strong end of year mark you could do it.
So I'd basically need to get an A+ to get it?
Post by: Studyinghard on June 09, 2010, 07:35:20 pm
Haven't been around the VCE system for a while now, but with a very strong end of year mark you could do it.
44 scaled? so like 41 raw???!?!?!?!?!
Post by: chansthename on June 09, 2010, 07:39:22 pm
thanks
Post by: Russ on June 09, 2010, 07:40:47 pm
44 scaled? so like 41 raw???!?!?!?!?!
Can't remember, sorry. Why does it matter?
Quote
So I'd basically need to get an A+ to get it?
Depends whether you meant raw or scaled actually, scaled will obviously be less. But 35/36 is achievable with a B+ on the midyear (from my experience with one of my subjects :S)
Post by: rubiks on June 09, 2010, 07:44:46 pm
Post by: Russ on June 09, 2010, 07:48:48 pm
I meant raw. What do you think I'd be looking at if I were to get an A on the end of year and A for SACs?
I have no idea, but I ran it through ENTER calculator and based on the 2008 scaling reports an overall B+ is between 32-36. So if you had B+ and an A, it would be skewed towards the upper end of that interval.
Talk to your teacher though, they'll have a more accurate idea :)
Post by: rubiks on June 09, 2010, 07:50:24 pm
I meant raw. What do you think I'd be looking at if I were to get an A on the end of year and A for SACs?
I have no idea, but I ran it through ENTER calculator and based on the 2008 scaling reports an overall B+ is between 32-36. So if you had B+ and an A, it would be skewed towards the upper end of that interval.
Talk to your teacher though, they'll have a more accurate idea :)
Ok, thanks. That makes me feel a little better lol
Post by: s2lindah on June 09, 2010, 07:56:05 pm
Ouch.. I forgot all about sig figs... would that be -1 off for every question?
Post by: stonecold on June 09, 2010, 07:56:47 pm
THANKS MAO!
Ouch.. I forgot all about sig figs... would that be -1 off for every question?
Nah just one mark on the whole paper.
Post by: bubsy on June 09, 2010, 08:00:02 pm
Wasn't question 9.a asking about the alkanols in the mixture collected once it had been distilled?THAT'S WHAT I THOUGHT SJKHDSKHSDHKFSKHSFDHFHSKJ AMBIGUOUS WORDING
"The first fraction is collected at 97.2 degrees."
"Identify one alkanol which could not be present in this mixture."
>________<
I read it as a connected sentence, not realising that the "mixture" referred to the actual mixture of compounds. Hate.
Post by: Mao on June 09, 2010, 08:00:15 pm
You can, by controlling the gas flow rate (there's always a valve there).Could you say not to use a bunsen burner as you have no control over the termperature Mao?
No, the temperature can be easily controlled by using adjusting the flame while looking at a thermometer.
but it changes constantly doesnt it? you cant exactly "control" the flame.
The misconception here is if you want to heat the gas to 90 degrees, the heat source must be 90 degrees. This is not true, the heat source is always a lot higher, even if a hot plate is used. The amount of energy delivered is dependant on both the temperature and the size of the heating source. Using a heat source of 300 degrees will not necessarily heat the mixture to 300 degrees, and if the size of the heat source is controlled, you can either heat it up rapidly (high flame) or slowly (low flame).
Another thing to consider is latent heat of vapourization (the temperature of a mixture stays constant if a component is vapourizing).
Post by: johsephhh_ on June 09, 2010, 08:01:33 pm
Post by: bubsy on June 09, 2010, 08:01:45 pm
Can an answer for 9b haveI said that the alkanols were combustible, but now i think i'm wrong. uh oh.
the bunsen burner varies in temperature therefore it is hard to keep a constant temperature and have a good separation of mixtures.
Post by: coletrain on June 09, 2010, 08:03:24 pm
Any chance of 40 with high A/low A+? what would be required end of year?
I got an A/A+ on the two chem exams (with A+ for coursework). My midyear A was one mark off the A+ cutoff and my end of year A+ was very high, can't remember the exact mark. I got a 44.xx scaled. So I would say, yes, you can still get 40.Quote35/36?
You have given me hope
Haven't been around the VCE system for a while now, but with a very strong end of year mark you could do it. (that's only my opinion though, someone else more familiar could give a better estimate)
Post by: bubsy on June 09, 2010, 08:04:05 pm
Meh, atm I concede 2 marks. I'm just praying that I filled out the MC answer sheet right.I did the same thing - I used the density formula and didn't realise that it was in mL, not L
I also pray that a bug crawls into my paper and takes a shit on page 21, right in between the 1 and the 5 so it looks like there is a decimal point and reads 1.5 L haha...
:P
Post by: johsephhh_ on June 09, 2010, 08:06:37 pm
Post by: Blakhitman on June 09, 2010, 08:07:22 pm
Post by: 98.40_for_sure on June 09, 2010, 08:09:23 pm
didnt pick up that the 22 carbons included the C from COOH fml
Post by: 98.40_for_sure on June 09, 2010, 08:12:20 pm
Post by: brendanbob on June 09, 2010, 08:16:37 pm
Post by: joocoobpootooloo on June 09, 2010, 08:17:14 pm
if i forgot to mention hydrogen bonding in regards to propan-1-ol but mentioned its polarity and dipole dipole bonds and that butane is non polar and has dispersion forces i might get the 3 marks? :S
Post by: Streaker on June 09, 2010, 08:28:49 pm
Post by: physics on June 09, 2010, 08:32:09 pm
and i think i wrote butane was polar by accident but i metioned the foorces and stuff so i should still get like 2 or 1 malrks out of 3 D: right right?
Post by: Sunny10 on June 09, 2010, 09:16:07 pm
Post by: crayolé on June 09, 2010, 09:17:59 pm
Post by: Studyinghard on June 09, 2010, 09:24:18 pm
Post by: Blakhitman on June 09, 2010, 09:24:38 pm
would you get the mark?
Post by: darkphoenix on June 09, 2010, 09:26:17 pm
Post by: Blakhitman on June 09, 2010, 09:26:54 pm
What is wrong with 3:1 . that is the answer isnt it? it asked for ratio. so you cant just write 3. infact 3 would almost be wrong.
It gave the calcuation you had to carry out,
and that gave an answer of 3.
Post by: chansthename on June 09, 2010, 09:28:15 pm
What is wrong with 3:1 . that is the answer isnt it? it asked for ratio. so you cant just write 3. infact 3 would almost be wrong.
it asked for:
number of moles of methanol/number of moles of POP
so I believe 3 is acceptable.
Should they have asked number of moles of methanol:number of moles of POP
Then you would be required to write 3:1
My understanding anyway
Post by: kakar0t on June 09, 2010, 09:29:49 pm
Post by: akira88 on June 09, 2010, 09:31:33 pm
BYE BYE A+ :(Same here :( :(
stupid misinterpretations cost me like 10 marks at least
omfg... i put C23H34O2I did the same ****ing thing. I put in C22H33COOH AND DIDNT TAKE AWAY THE C FROM COOH.
didnt pick up that the 22 carbons included the C from COOH fml
so depressing. Turns out this exam wasn't so easy.....(not that I thought it was, well it was definitely easier than last year's for sure...)
Post by: andy456 on June 09, 2010, 09:36:14 pm
Post by: Studyinghard on June 09, 2010, 09:37:46 pm
What is wrong with 3:1 . that is the answer isnt it? it asked for ratio. so you cant just write 3. infact 3 would almost be wrong.
it asked for:
number of moles of methanol/number of moles of POP
so I believe 3 is acceptable.
Should they have asked number of moles of methanol:number of moles of POP
Then you would be required to write 3:1
My understanding anyway
Nope i disagree because ratio always is X:Y. not just X.
however I think 3 will be acceptable.
and so will 3:1. but I think 3:1 is a better answer. (obviously cause I wrote it)
Post by: stonecold on June 09, 2010, 09:38:23 pm
what about 3 DIVIDED BY 1 methods style?
I did this. If they take a mark off for this, they can go fuck themselves. There is nothing wrong with it.
Tbh, I am pissed that that question was even on there. That, plus the bolded triglyceride gave away the hint that the ratio wasn't 1:1. Therefore more people get it right, which stinks.
Post by: vietp123 on June 09, 2010, 09:39:48 pm
Post by: crayolé on June 09, 2010, 09:40:15 pm
Doesnt value mean just one number?
Post by: appianway on June 09, 2010, 09:41:04 pm
Post by: stonecold on June 09, 2010, 09:41:40 pm
Post by: Studyinghard on June 09, 2010, 09:43:11 pm
Damn, just reread the question, it asked for the value of the stoichiometric ratio
Doesnt value mean just one number?
how can you have a value of the ratio? that doesnt even make sense ! or does it? SIGH
Post by: matt123 on June 09, 2010, 09:44:21 pm
just looked at the exam
made simple mistakes .. forgot to put in states for reactions
forgot to put the H+ with cr2072-
forgot to draw 0- on the structure
forgot it was 7 bonds instead 6 and also i messed up the formula
stuffed up the units of one of the questions
messed up bunsen burner question
i calculated .. about 65% .... thats a C .... im so anoy
Post by: Stormer on June 09, 2010, 09:45:17 pm
Post by: hyperblade01 on June 09, 2010, 09:45:25 pm
MC 13 - First thing that popped into my mind was electrophilic and nucleophilic attack :P So tempted to write out the mechanisms as well ;)
Post by: stonecold on June 09, 2010, 09:46:08 pm
Damn, just reread the question, it asked for the value of the stoichiometric ratio
Doesnt value mean just one number?
how can you have a value of the ratio? that doesnt even make sense ! or does it? SIGH
I know. Absolute shit question. As long as you recognised it was 3:1, why should you not be eligible for the mark. You interpreted everything correct.
Post by: matt123 on June 09, 2010, 09:46:26 pm
then i stuffed up the EASIEST exam today
so angry
Post by: appianway on June 09, 2010, 09:47:49 pm
Post by: taiga on June 09, 2010, 09:49:34 pm
Don't worry, I was getting about 100% on most of my trials, but alas, on the one that actually counted... I think most people here did a lot worse than expected.
True. I didn't make any major mistakes, but I think i lost one mark for about 3 or 4 seperate questions :(
Post by: matt123 on June 09, 2010, 09:50:32 pm
misread the question and accidently said there is 137 double bonds
lmfao fml
Post by: Studyinghard on June 09, 2010, 09:50:37 pm
Damn, just reread the question, it asked for the value of the stoichiometric ratio
Doesnt value mean just one number?
how can you have a value of the ratio? that doesnt even make sense ! or does it? SIGH
I know. Absolute shit question. As long as you recognised it was 3:1, why should you not be eligible for the mark. You interpreted everything correct.
if they dont give me a mark for that ima personally go to the examiners house and ..................SCREAM AT HIM.
Post by: Akirus on June 09, 2010, 09:50:52 pm
Damn, just reread the question, it asked for the value of the stoichiometric ratio
Doesnt value mean just one number?
how can you have a value of the ratio? that doesnt even make sense ! or does it? SIGH
I know. Absolute shit question. As long as you recognised it was 3:1, why should you not be eligible for the mark. You interpreted everything correct.
I doubt they'll penalize that as long as you got the ratio correct, I don't see why they would be that anal about it.
Post by: stonecold on June 09, 2010, 09:51:31 pm
Next exam will be the one that counts anyway...
Post by: kenhung123 on June 09, 2010, 09:52:24 pm
made a huge major mistakehehe...sorry thats a bit funny :P
misread the question and accidently said there is 137 double bonds
lmfao fml
Post by: appianway on June 09, 2010, 09:52:56 pm
Post by: darkphoenix on June 09, 2010, 09:53:07 pm
made a huge major mistake
misread the question and accidently said there is 137 double bonds
lmfao fml
LMAO i got 5, but i worked it out to be 6, too bad it was just my own random working out, so ill prob get 0 for that FML
Post by: matt123 on June 09, 2010, 09:53:14 pm
65%
see ya later any chance at 97 enter .... means i got a C at best a B+ . .meas ill end up with a study score of 30-35
means .... im farked
Post by: Studyinghard on June 09, 2010, 09:53:29 pm
made a huge major mistakehehe...sorry thats a bit funny :P
misread the question and accidently said there is 137 double bonds
lmfao fml
lol i though that too. just didnt wanna say anything. 137 double bonds would have had to strike that somethign was wrong :P
Post by: stonecold on June 09, 2010, 09:55:21 pm
Draw the acid. rofl, that would have been torture...
Post by: Davoo! on June 09, 2010, 09:56:20 pm
Stupid errors bloody hell. This is worse than the physics exam where they had a question wedged in between two useless pieces of info and so many people missed it.
Post by: Blakhitman on June 09, 2010, 09:56:45 pm
Post by: matt123 on June 09, 2010, 09:56:51 pm
Post by: Studyinghard on June 09, 2010, 09:57:39 pm
imagine if the next question was:
Draw the acid. rofl, that would have been torture...
LOLOLOL.
sigh you know you wanna kill yourself when you do 33 mmol x 180 into your calculator
when the line before you wrote 30mmol x 180 and gett the wrong grams. 1 mark. just like that.
Post by: samuch on June 09, 2010, 09:58:01 pm
do u think i have any chance of a B or a B+ with 65% ?maybe a B
Post by: matt123 on June 09, 2010, 09:58:59 pm
kus that lowers my enter to like .. maybe 88-90
Post by: stonecold on June 09, 2010, 09:59:37 pm
imagine if the next question was:
Draw the acid. rofl, that would have been torture...
LOLOLOL.
sigh you know you wanna kill yourself when you do 33 mmol x 180 into your calculator
when the line before you wrote 30mmol x 180 and gett the wrong grams. 1 mark. just like that.
don't worry, I somehow managed to turn 1458mL into 15 L like a douchebag! :(
Post by: Blakhitman on June 09, 2010, 10:00:58 pm
64/75 i rckon.. probs lower :/ fuck vce lol i wanted A+ soo bad
After revising the exam thoroughly, looks like I'm in the same boat as you >.<.
ahh not exactly happy.
Post by: Studyinghard on June 09, 2010, 10:04:28 pm
Post by: Blakhitman on June 09, 2010, 10:05:18 pm
hopefully coz of all these mistakes the A+ goes down :P....
who else went nuts and was thinking they got it all right after haha?... bugger :P
haha I was on the verge of running around the school yelling "A+! A+!".
Post by: stonecold on June 09, 2010, 10:09:39 pm
As soon as I walked out they said it was 49 peptide bonds when I was confident I got it all right. and i was like wow 1 minute after the exam and 1 mark gone. lets hope this isnt a straight line equation XD
lol, i like your anology. yeah, I was supremely confident after the exam, but not really anymore...
Post by: kenhung123 on June 09, 2010, 10:10:20 pm
Post by: crayolé on June 09, 2010, 10:13:34 pm
Post by: kenhung123 on June 09, 2010, 10:15:13 pm
Post by: stonecold on June 09, 2010, 10:17:54 pm
:p
Post by: matt123 on June 09, 2010, 10:18:48 pm
do any of u actauly know eachother in real life
Post by: Blakhitman on June 09, 2010, 10:19:20 pm
Post by: linahh123 on June 09, 2010, 10:20:39 pm
Post by: Blakhitman on June 09, 2010, 10:22:01 pm
Post by: crayolé on June 09, 2010, 10:25:07 pm
And matt, I don't think there are many social friends around here but many of us have definitely met each other a few times at lectures/XLL/interschool activities etc.
I've met a couple from buying books, been face to face with stonecold and we didnt know it till afterwards. Sat one seat away from
Post by: linahh123 on June 09, 2010, 10:26:30 pm
well 80 would definitely get you an A, so high 70s, definitely B+ but possibly an A
I really hope so. Hmmm...I'm beginning to feel like the cut off for A+ won't be as high as every1 initially expected. GOOD LUCK EVERYONE!
Post by: matt123 on June 09, 2010, 10:26:57 pm
do you people talk about stuff here throughout the year
or just during exams?/
i was playing a game and one guy told me this blog and im so thankful for it
people really nice and good feedback and ideas
Post by: Blakhitman on June 09, 2010, 10:27:27 pm
LMAO stonecold, nerves had got me so bad it was nowhere near legible. You know I wrote especially neat just for you guys anyway :P <3 :smitten:
And matt, I don't think there are many social friends around here but many of us have definitely met each other a few times at lectures/XLL/interschool activities etc.
I've met a couple from buying books, been face to face with stonecold and we didnt know it till afterwards. Sat one seat away from Blak in a huge ass lecture room when it was like the only seat left in the room LOL
By Blak you don't mean me do you?
Post by: stonecold on June 09, 2010, 10:28:38 pm
Post by: appianway on June 09, 2010, 10:28:51 pm
Post by: linahh123 on June 09, 2010, 10:29:05 pm
LMAO stonecold, nerves had got me so bad it was nowhere near legible. You know I wrote especially neat just for you guys anyway :P <3 :smitten:
And matt, I don't think there are many social friends around here but many of us have definitely met each other a few times at lectures/XLL/interschool activities etc.
I've met a couple from buying books, been face to face with stonecold and we didnt know it till afterwards. Sat one seat away from Blak in a huge ass lecture room when it was like the only seat left in the room LOL
AHAHAHA next thing you know, vn is going to turn into a dating site xD
Post by: matt123 on June 09, 2010, 10:29:28 pm
Post by: crayolé on June 09, 2010, 10:30:59 pm
Was it you I sat next to at free bio lectures?
Matt, we're here all year round so feel free to stay ;L
Post by: Blakhitman on June 09, 2010, 10:32:04 pm
Yeah, I'm ex-Tezza LOL
Was it you I sat next to at free bio lectures?
Matt, we're here all year round so feel free to stay ;L
haha nope, IIRC it was kingpomba?
Post by: matt123 on June 09, 2010, 10:33:02 pm
yeaah
i mean honestly i effffed my exams up so hard after a constant 4-5 hours study a night for 5 months
so im very very dissapointed
i guess if i want any chance in getting over 90+ im gonna have to work harder ( somehow) this semester
thanks guys :) i appreciate everyones help
Post by: crayolé on June 09, 2010, 10:33:56 pm
Thats right, how did you know it was him? LOL
Post by: linahh123 on June 09, 2010, 10:34:40 pm
You're off to such a great start you got 44 for P.E!! You'll definitely do well ;)
Post by: akira88 on June 09, 2010, 10:35:06 pm
I thought I did well before I went on VN lolDitto.
It sucks how one stupid little mistake can cost you a mark- if you think about it, its just basically the same as not knowing the answer in the first place- 0 marks if you dont know the answer, 0 marks if you screw it up.
Exams suck :P
Post by: matt123 on June 09, 2010, 10:36:53 pm
sooo dissapointed
hmmmmmmmmmmmmmm
umm yeah i got 44 for pe .. but im crap at english and i dont know if ill pass methods .. ill be lucky to get a SS of 20 rofl
righto .. just hope i get in the 90;s now ...
Post by: stonecold on June 09, 2010, 10:37:54 pm
Cost of fine for not having a ticket = Cost of fine for travelling on a concession ticket without a 'valid' concession.
You get screwed either way!
Post by: Blakhitman on June 09, 2010, 10:39:43 pm
OMG how embarassing LOL
Thats right, how did you know it was him? LOL
I don't know, I retain useless information which I read.
Isn't really that helpful when it comes to exams LOL.
Post by: matt123 on June 09, 2010, 10:40:16 pm
chem exam
i said 1:3 so pissed off
also .. i forgot to put the 3 concordant results
also i forgot thats it H+/Cr2072- .. not just cr2072-
and also stuffed the " wahts missing question" said h20 instead 0h-
also stuffe 6 multiple choice questions
lol dude i got suggested answers from 2 examiners
and i calculated my score to be 65%, C+
fml so anoyed
Post by: matt123 on June 09, 2010, 10:40:43 pm
have a good night
goodluck with the marks :)
talk soon
Post by: Blakhitman on June 09, 2010, 10:42:42 pm
Post by: stonecold on June 09, 2010, 10:43:09 pm
Post by: Studyinghard on June 09, 2010, 10:46:23 pm
Post by: mroberts on June 09, 2010, 10:47:13 pm
Post by: brendanbob on June 09, 2010, 10:53:56 pm
yeah made so many mistakes 65% chem ... 85% psych .. 80% bio . like .. C+ , A , A
sooo dissapointed
hmmmmmmmmmmmmmm
umm yeah i got 44 for pe .. but im crap at english and i dont know if ill pass methods .. ill be lucky to get a SS of 20 rofl
righto .. just hope i get in the 90;s now ...
i think im on the same level as you matt :) i think i might have gotten 62% for chem, 85% for bio, but 60% for physics, *crossing my fingers for 90+ as an enter score though*
Post by: kenhung123 on June 09, 2010, 10:56:27 pm
Do you really need the H+? Because it says a reagent. not reagent-SPeople here are saying you do but this is quite a typical question in trials and I seem to always seem K2Cr2O7, Cr2O7^2-, KMno$, MOn4- with or without acidification
Post by: doubl3cho on June 09, 2010, 10:57:20 pm
I lost a total of 19 marks, and seeing as I thought I did really well, once again I bombed out on the exam and failed massively. Pretty disappointed at myself. GL TO EVERYBODY ELSE :D
Post by: kenhung123 on June 09, 2010, 10:57:32 pm
this is great, however in Q9 if it is the first fraction why should methanol/ethanol not be present as 97.2 is above their boiling point, i thought they would just rise through the fractionating column and be collected in the receiving flask therefore being present in the first fractionYea that is so tricky! The referred mixture as the thing that is still in the flask! not collected! Yep, hard feelings..
Post by: vexx on June 09, 2010, 10:57:39 pm
you have suggested solutions from examiners????
so many teachers are examiners, maybe two at his school is? i know my teacher is an assessor this year, and also the other chem teacher might too. i'm going to speak to mine on friday about things, maybe they have already got the assessor's suggested answers....
Post by: Blakhitman on June 09, 2010, 10:59:24 pm
But even then, examiners can't teach, assessors yes but not examiners :P.
Post by: stonecold on June 09, 2010, 11:00:27 pm
Yeah I believed him, I was just surprised he didn't share! lol.
But even then, examiners can't teach, assessors yes but not examiners :P.
Other way around I believe.
Post by: vexx on June 09, 2010, 11:00:45 pm
Yeah I believed him, I was just surprised he didn't share! lol.
But even then, examiners can't teach, assessors yes but not examiners :P.
oh i assumed examiner as someone who marks an exam xD (=assessor)
Post by: Blakhitman on June 09, 2010, 11:01:16 pm
Post by: Studyinghard on June 09, 2010, 11:01:32 pm
Post by: vexx on June 09, 2010, 11:02:01 pm
Don't examiners write the exam?
exam writers write the exams, examiners mark the exam :o?
errr...
Post by: Blakhitman on June 09, 2010, 11:04:54 pm
Post by: stonecold on June 09, 2010, 11:05:26 pm
examiners just mark the exam according to a set of marking criteria they are given after the exam, so they can teach.
and examiners don't have to be good teachers or anything. both of my awful english teachers mark exams, as well as my chemistry one who didn't know the rules for sig figs... *sighs*
Post by: vexx on June 09, 2010, 11:08:03 pm
I thought assessors write the study design/exam and therefore can't teach.
examiners just mark the exam according to a set of marking criteria they are given after the exam, so they can teach.
and examiners don't have to be good teachers or anything. both of my awful english teachers mark exams, as well as my chemistry one who didn't know the rules for sig figs... *sighs*
haha yeah they just follow rules, to be one you just send an email to vcaa with number of exams you want and thats it..:P
Post by: darkphoenix on June 09, 2010, 11:10:25 pm
One is the best, the other is the worst.
Post by: vexx on June 09, 2010, 11:13:49 pm
Our school has 2 examiners for Accounting.
One is the best, the other is the worst.
it's funny when teachers think they are top because they mark exams
"well i know because im an exam marker."
"everyone! calm down! i'm an exam marker! dont worry!"
><
Post by: kenhung123 on June 09, 2010, 11:15:29 pm
I thought assessors write the study design/exam and therefore can't teach.awesome i hope she marks mine lol!
examiners just mark the exam according to a set of marking criteria they are given after the exam, so they can teach.
and examiners don't have to be good teachers or anything. both of my awful english teachers mark exams, as well as my chemistry one who didn't know the rules for sig figs... *sighs*
Post by: stonecold on June 09, 2010, 11:16:47 pm
Post by: vexx on June 09, 2010, 11:19:24 pm
Hmm, I wonder if a send an email saying I wan't to mark exams from [email protected] if they will let me lol. I'll get everyone from VN's papers and give 100% to all of you. :)
woohoooo physics 09!!!
Post by: crayolé on June 09, 2010, 11:20:43 pm
That is so true :LOur school has 2 examiners for Accounting.
One is the best, the other is the worst.
it's funny when teachers think they are top because they mark exams
"well i know because im an exam marker."
"everyone! calm down! i'm an exam marker! dont worry!"
><
My methods teachers boasts about being an exam marker for many years
I havent learnt anything or done anything since we got her
Post by: darkphoenix on June 09, 2010, 11:21:39 pm
That is so true :LOur school has 2 examiners for Accounting.
One is the best, the other is the worst.
it's funny when teachers think they are top because they mark exams
"well i know because im an exam marker."
"everyone! calm down! i'm an exam marker! dont worry!"
><
My methods teachers boasts about being an exam marker for many years
I havent learnt anything or done anything since we got her
Haha yeah i reckon, when i first found out i was wtf seriously? how can she be an examiner?
Post by: kenhung123 on June 09, 2010, 11:22:46 pm
Post by: humadeee on June 09, 2010, 11:22:59 pm
tbh this exam was probably worse than last year. not because I think I did bad but more so because it didn't test about your level of chemistry but more about how many tricks they tried to fit into the exam. Feels like their main intention wasn't to test our chemistry knowledge but more to pick the ones who make the silly mistakes.
I agree... last year's methods CAS exam 1 was like this too.
Sucks.
Post by: vexx on June 09, 2010, 11:23:10 pm
That is so true :LOur school has 2 examiners for Accounting.
One is the best, the other is the worst.
it's funny when teachers think they are top because they mark exams
"well i know because im an exam marker."
"everyone! calm down! i'm an exam marker! dont worry!"
><
My methods teachers boasts about being an exam marker for many years
I havent learnt anything or done anything since we got her
Haha yeah i reckon, when i first found out i was wtf seriously? how can she be an examiner?
haha. yeah it's such a shock at some who can just become exam markers... the prereq is just being a teacher though, my englang teacher marks english papers and she only teaches yr11 english :P
Post by: stonecold on June 09, 2010, 11:24:32 pm
Post by: phoebeshiu on June 09, 2010, 11:38:50 pm
Post by: Blakhitman on June 09, 2010, 11:39:44 pm
Post by: phoebeshiu on June 09, 2010, 11:41:22 pm
Post by: Blakhitman on June 09, 2010, 11:42:25 pm
But 20.03 had a 0.06 difference with the other titres.
concordant is with 0.1
so 20.03 counts
I have never heard this, always been plus or minus 0.05!
Post by: kyzoo on June 09, 2010, 11:44:42 pm
tbh this exam was probably worse than last year. not because I think I did bad but more so because it didn't test about your level of chemistry but more about how many tricks they tried to fit into the exam. Feels like their main intention wasn't to test our chemistry knowledge but more to pick the ones who make the silly mistakes.
That's the truth about VCE Maths + Sciences. Everything is about avoiding the tricks rather than knowing everything. There are some exceptions though, the 2.0m/s^2 vs 2.5m/s^2 pulley question in Physics was more about concepts than tricks.
Post by: phoebeshiu on June 09, 2010, 11:46:09 pm
Post by: Akirus on June 09, 2010, 11:46:31 pm
tbh this exam was probably worse than last year. not because I think I did bad but more so because it didn't test about your level of chemistry but more about how many tricks they tried to fit into the exam. Feels like their main intention wasn't to test our chemistry knowledge but more to pick the ones who make the silly mistakes.
That's the truth about VCE Maths + Sciences. Everything is about avoiding the tricks rather than knowing everything. There are some exceptions though, the 2.0m/s^2 vs 2.5m/s^2 pulley question in Physics was more about concepts than tricks.
That + energy question.
Post by: Blakhitman on June 09, 2010, 11:46:45 pm
bah I really don't care anymore.
Post by: kenhung123 on June 09, 2010, 11:51:27 pm
Does it really matter, you should really just pick the 3 closest ones lol..But 20.03 had a 0.06 difference with the other titres.
concordant is with 0.1
so 20.03 counts
I have never heard this, always been plus or minus 0.05!
Post by: Blakhitman on June 09, 2010, 11:53:13 pm
Post by: akira88 on June 09, 2010, 11:56:50 pm
It said concordant, and according to the way I was taught, they weren't concordant.I did what you did, and I was also taught that it was plus/minus 0.05.
VCAA seriously cannot take marks for us identifying a wrong concordant titre. *Whines like baby*
Post by: crayolé on June 10, 2010, 12:00:30 am
I'm pretty sure you'll get the mark since textbooks state the .05 rule
Post by: akira88 on June 10, 2010, 12:04:12 am
Yeah i thought it was +-.05mL too but i was so nervous i just thought they looked close enough so i just went ahead and used the threePhew I hope so. At least that's one mark salvaged :)
I'm pretty sure you'll get the mark since textbooks state the .05 rule
I was really really worried today, but now I'm starting to forget about it... very slowly.... haha :P
Post by: Blakhitman on June 10, 2010, 12:06:53 am
Post by: vexx on June 10, 2010, 12:09:42 am
Post by: Blakhitman on June 10, 2010, 12:11:58 am
Post by: akira88 on June 10, 2010, 12:14:37 am
Yeah I cbf caring anymore, I'm going to bed.Night. Me too. Realised I've lost >10 marks. Beyond caring now.
Sleep well for the GAT everyone :D
Post by: kayjay on June 10, 2010, 12:20:38 am
Post by: Mao on June 10, 2010, 12:22:46 am
Post by: cama23 on June 10, 2010, 01:05:59 am
lets hope vcaa assessors arent tightarses.
taking marks off for writing 3/1 or 3:1 or 3 is pointless and isnt testing what you know about stochiometry...
Post by: darkphoenix on June 10, 2010, 03:42:03 pm
The assessors (people who mark exams) will probably meet this weekend or next weekend to discuss answers. I will leak that there is at least one assessor that i know of who lurks vn. This person will probably read this threads and acknowledge the disputes over some ambiguous things, inc the concordant titre and ratio thing, and your concerns may be raised in this meeting. So not all is lost. :)
Any chance of pity marks? LOL
Post by: phoebeshiu on June 10, 2010, 03:52:39 pm
Time to start Unit 4 and work harder for that exam.
Post by: darkphoenix on June 10, 2010, 04:23:56 pm
Post by: Twenty10 on June 10, 2010, 04:28:29 pm
tbh this exam was probably worse than last year. not because I think I did bad but more so because it didn't test about your level of chemistry but more about how many tricks they tried to fit into the exam. Feels like their main intention wasn't to test our chemistry knowledge but more to pick the ones who make the silly mistakes.
Yep.. and the worst part is teachers tell you about how the exam is designed to test your knowledge and not to trick you. Turns out they where wrong. X|
Post by: crayolé on June 10, 2010, 04:33:46 pm
Post by: samiira on June 10, 2010, 04:36:04 pm
Post by: vexx on June 10, 2010, 04:36:31 pm
Post by: Blakhitman on June 10, 2010, 04:39:12 pm
when do our results come..??
August 2nd!
Post by: Studyinghard on June 10, 2010, 04:42:02 pm
True, something like last year was perfect, why did they have go down that path
i think they just got annoyed because everyone complained that last year was too hard so now they just wanted to have some fun. =[
Post by: darkphoenix on June 10, 2010, 05:02:09 pm
last year wasnt even that hard? i just reckon no one was ready coz they had a simple 08..
Some of the 'interpreting' ones were kinda tricky, but yeah they didn't have much to practice on, so yeah made it harder.
Post by: Studyinghard on June 10, 2010, 05:13:19 pm
last year wasnt even that hard? i just reckon no one was ready coz they had a simple 08..
Yeah but people still complained about it. Im not saying it was hard. heck I would have preferred last year's exam compared to this year.
Post by: will74 on June 10, 2010, 05:50:52 pm
Post by: kenhung123 on June 10, 2010, 05:55:04 pm
do you think that vcaa could ever give consequential marks for a misinterpreted question? like quite a few people got the last question wrong as they thought it meant something else - could they get a mark for the explanation but a mark off for the actual answer? or definitely get both wrong?The explanation for the last question works both ways assuming the misinterpretation meant your didn't know which mixture.
Post by: Studyinghard on June 10, 2010, 06:33:04 pm
shitt did we have to write OH- for Question 8bii....i wrote OH, no minus
Nope I dont think we had to write -OH. it doesnt even make sense for it to be negatively charged in the molecule.
Post by: kenhung123 on June 10, 2010, 07:10:30 pm
Post by: 8039 on June 10, 2010, 07:25:58 pm
The original electron AND the one knocked off?
Post by: kenhung123 on June 10, 2010, 07:30:47 pm
Post by: year12 on June 10, 2010, 09:22:05 pm
Mao can you explain your reasoning behind your answer of 2 for the question: "The signal at 1.3 ppm is split into a triplet. What is the number of equivalent protons bonded to the adjacent carbon atom?" (Page 13)n+1 rule
3 peaks means it's got two adjacent hydrogens
But to form splits in the peaks, the hydrogens have to be in different environments , i.e. in non-equivalent environments. Which means there are zero protons bonded to the adjacent carbon that are equivalent.
From KBT solutions :"If the hydrogens of a particular environment have n neighbouring, non-equivalent hydrogens,
the peak from that environment will be split into n+1 component peaks.
Keep in mind that the word ‘neighbouring’ as it’s used above means ‘on the adjacent carbon
atom’. ‘Non-equivalent’ means ‘not of the same environment’."
(http://www.kbtlectures.com/wp-content/uploads/2010/04/KBT_unit3chemistry_trialexamsolutions.pdf)
Yes, I agree! I wrote '0 (none)' yesterday as well because of the question didn't say 'NON-equivalnet'.
Post by: kenhung123 on June 10, 2010, 09:29:31 pm
Post by: year12 on June 10, 2010, 09:30:48 pm
Can an answer for 9b have
the bunsen burner varies in temperature therefore it is hard to keep a constant temperature and have a good separation of mixtures.
I'm praying yes...
That's what I wrote as well! Hope the asseors accept it!
Post by: ashwin on June 10, 2010, 09:35:50 pm
Post by: year12 on June 10, 2010, 09:48:29 pm
Post by: kenhung123 on June 10, 2010, 09:52:43 pm
Post by: stonecold on June 10, 2010, 10:30:00 pm
"The temperature of the fractioning column can not be controlled if a bunsen burner is used."
?
It's only because we are in classrooms, and our sucky bunsen burners can't really be controlled, and the flow of the gas can't be either...
Post by: kakar0t on June 10, 2010, 10:32:08 pm
Post by: 8039 on June 10, 2010, 10:33:49 pm
What about "the glassware may become too hot and break"? hahahaha
hahaha that's what I was thinking. But then was like, we used that in an experiment so can't be. I just wrote it's too hard to get the right temperature -_-
Post by: Mao on June 10, 2010, 10:40:33 pm
As for the safety question, it was definitely testing you about naked flame/light combustibles.
Post by: stonecold on June 10, 2010, 10:46:38 pm
Don't you hate it when your torn between two answers. That was my second answer. I should have put down both...
Post by: vexx on June 10, 2010, 11:33:03 pm
No! I wrote e- on the left hand side, instead of the right (the product side) for the first MS question!! NOOOOOO
although i'm not an assessor, perhaps this could be correct since your showing the bombardment of electrons? i'm not completely sure with the strictness of chemistry in vce yet, so i can't say!
i know someone who also did CH3CH2OH(g) +e- --> CH2CH2OH+(g), and i'm thinking that it may be correct. unless they think the leaving of electrons is very important..
Post by: crayolé on June 10, 2010, 11:45:30 pm
Okay, thanks Mao. :)Yeah same :/ I was going to use both in my answer but i ran out of room and just ceebs altogether
Don't you hate it when your torn between two answers. That was my second answer. I should have put down both...
Post by: kenhung123 on June 10, 2010, 11:52:57 pm
So there is no chance of the bunsen burner question having the answer:I reckon there isn't 1 set answer for that question....but of course they won't accept everything :P
"The temperature of the fractioning column can not be controlled if a bunsen burner is used."
?
It's only because we are in classrooms, and our sucky bunsen burners can't really be controlled, and the flow of the gas can't be either...
Post by: mayingjie_123 on June 11, 2010, 12:53:43 am
Post by: year12 on June 11, 2010, 02:03:20 pm
No! I wrote e- on the left hand side, instead of the right (the product side) for the first MS question!! NOOOOOO
although i'm not an assessor, perhaps this could be correct since your showing the bombardment of electrons? i'm not completely sure with the strictness of chemistry in vce yet, so i can't say!
i know someone who also did CH3CH2OH(g) +e- --> CH2CH2OH+(g), and i'm thinking that it may be correct. unless they think the leaving of electrons is very important..
Thanks for that! I guess there's no point is worrying any more (although I can't get over the fact that I only got 1.47ml for methanol volume - out by a factor of 1000) but I am definitely glad to hear that there might be some validity to what I wrote.
@may, what was Q13?
Post by: crayolé on June 11, 2010, 04:04:48 pm
Post by: Akirus on June 11, 2010, 04:15:05 pm
Oh my god, I have the worst teacher i swear. Went over the test the other day and he fucking says the ethyl methanoate was a ketone
My friends were telling me it was an aldehyde right after the exam.
Post by: stonecold on June 11, 2010, 04:16:36 pm
Oh my god, I have the worst teacher i swear. Went over the test the other day and he fucking says the ethyl methanoate was a ketone
How some people are allowed to teach has got me stuffed!
Post by: crayolé on June 11, 2010, 04:19:30 pm
Mhm, whole year has pretty much been self taught :zOh my god, I have the worst teacher i swear. Went over the test the other day and he fucking says the ethyl methanoate was a ketone
How some people are allowed to teach has got me stuffed!
Post by: Blakhitman on June 12, 2010, 01:56:06 pm
Post by: lisafaustina on June 12, 2010, 11:37:08 pm
and same goes with acidified dichromate. i didnt name it, i only just wrote Cr207/H+
Post by: vexx on June 12, 2010, 11:42:14 pm
did you have to write carbonyl along with C=O? Cos i just wrote C=O and didnt write carbonyl :(
and same goes with acidified dichromate. i didnt name it, i only just wrote Cr207/H+
Cr207^2-/H+ is correct, and for the C=O they only said name the atoms and bond between them, so perhaps saying C double bond O was correct? XD since they didn't specify what type of bond..hehe
Post by: kenhung123 on June 13, 2010, 07:46:25 am
Post by: kenhung123 on June 13, 2010, 07:47:24 am
Post by: chansthename on June 16, 2010, 05:45:03 pm
Do you think that was like the lead up to the double bond question trick? Trying to remind us that C=O is in fact a double bond...?
lol, that would help legitimise taking marks off fror not having 7.
Post by: stonecold on July 15, 2010, 11:31:21 pm
-6 double bonds will be accepted. If you said 7, you had to explain why.
-3/1 is being accepted for the value of the stoichiometric equation question.
-Bunsen burner questions has a range of answers, and when I said 'temperature control' to her, she didn't say it was wrong so I am pretty sure this is being accepted.
Hopefully everyone will pick up some extra marks now. :)
A+ is also looking high, it may be in the 90's, but don't speculate too much.
Edit: Just to make it clear, she is an exam marker.
Post by: m@tty on July 15, 2010, 11:37:01 pm
My chem teacher today told me that:
-6 double bonds will be accepted. If you said 7, you had to explain why.
-3/1 is being accepted for the value of the stoichiometric equation question.
-Bunsen burner questions has a range of answers, and when I said 'temperature control' to her, she didn't say it was wrong so I am pretty sure this is being accepted.
Hopefully everyone will pick up some extra marks now. :)
A+ is also looking high, it may be in the 90's, but don't speculate too much.
That is soo good =)
And about the double-bond question: that is exactly what I thought initially! haha
Post by: vexx on July 15, 2010, 11:47:24 pm
zzzz i hope its not in the 90s :/
i think we are all hoping that too ><
Post by: andy456 on July 16, 2010, 08:48:00 am
My chem teacher today told me that:Did she give any indication as to whether the cut-offs are higher or lower than 2008's??
-6 double bonds will be accepted. If you said 7, you had to explain why.
-3/1 is being accepted for the value of the stoichiometric equation question.
-Bunsen burner questions has a range of answers, and when I said 'temperature control' to her, she didn't say it was wrong so I am pretty sure this is being accepted.
Hopefully everyone will pick up some extra marks now. :)
A+ is also looking high, it may be in the 90's, but don't speculate too much.
Edit: Just to make it clear, she is an exam marker.
Post by: Studyinghard on July 18, 2010, 09:05:59 pm
Post by: lisafaustina on July 18, 2010, 11:14:59 pm
Post by: 8039 on September 30, 2010, 05:22:33 pm
1. How do I solve question 3 and 4 and 5? and I keep getting D for question 18?
2. How do we calculate the amount of double bonds in general (wasn't in the book)? and the formula for Cervaic acid?
3. 6.d this question confused the heck outta me. Can anyone explain what I had to do?
3. For 7.a.i. Is POP just a basic triglyceride structure that happens to come from coconut oil?
4. Do we need to know about intermolecular forces for unit 4?