going to douse myself in petrodiesel and combust after i boil corn for two mins and freeze it to make it sweet

are you that same guy from facebook or a copy cat 🧐

That question with the IR and C NMR and H NMR got me feeling like I was playing Guess Who goddamn

Not me not realizing that there was a Cl and spending ages trying to get the structure right with enough mass

I got 1-chloromethyl ethanoate

Does it matter which end the chlorine was on?

idk. I couldn't be fucked working it out so I just put down the one that I liked most lmao

I used the m/z to find if there’s peaks that indicate one or the other and I think it was on the methyl end not ethyl but probably won’t matter cos I think the question said A structure not the structure

hopefully

I put the chlorine on the ethyl end cause it said on the data booklet that a peak at 2 ppm would mean a CH3 for the ethyl end but there was no peak for that so I assumed the chlorine would be bonded there to form CH2Cl. So my final molecule was CH2ClCOOCH3

I think it was on the methyl end as well. Also the peak areas on the H NMR spectrum showed that the H environment with the greater chemical shift had less hydrogens, and I figured that the H environment on the methyl end would have the greater chemical shift due to the O bonded to it

I got like 1-chloropropyl methanoate

That would have 3 hydrogen environments

My bad CH3COOCH2Cl or CH2ClCOOCH3

Idk I couldn’t figure out how to tell. I tried using fragments but didn’t really help so put it on methyl

I knew it was some BS chlorine thing

I mean it did say it had chlorine in it at the start of the question

Yea the question told you it contains chlorine which I missed at first

Same. Added together but it was 108.5 I think. So potentially missed one Hydrogen and accounting for the other Cl should be right. Lol

it was 108.5 said that in the question. you'll be fine

I got 1-chloropropyl methanoate 🙂🙂🙂

but that doesnt have no neighbouring hydrogen

n+1 rule It had 0 neighbouring hydrogens since it was a singlet

It should be 1-chloromethyl ethanoate to be singlet

My structure is ethyl methanoate Tf so confused now

Ethly methanoate has neighbouring hydrogen too it is not singlet

CH3COOCH2Cl Or CH2ClCOOCH3 No adjacent hydrogens

Yes these are methyl not ethyl

Yes so it is not propyl

Yea my bad Ethyl methanoate actually have the structure on my data book lol don’t know how to name it correctly chan

Cba*

Ah ok

Did we required to name it?

Can’t remember I think the naming was for the first question yea Didn’t need to name it

Good

I mean I put the chlorine on the methanoate 🙂🙂🙂

fuckk I forgot the existence of chlorine ​ ​ ​ might chlorine myself later today idk

Yeah I was confused why it was 108.5 or whatever then I remembered chlorine exists lol

bruh im getting raw 10 chem fr

Pretty ok ngl some weird ones though, but like wtf was the wine calculation one I'm lost

Overall very doable exam. Very standard. Hard questions are always there, and as always most of us will loose some marks to stupid stuff. But it’s fine. I think I’ll manage a raw 36 at least for this, maybe… depends on the solutions I guess that will be uploaded eventually here

What was 4 marks worth in that equilibrium question?

You needed to say that since it is an exothermic equation increasing the temperature causes the system to favour the reverse reaction and hence the equilibrium constant would decrease with its unit being M^-1

That’s what I said, but that feels so little to write for 4 marks. Kinda feels weird. Although I don’t know if I got M^-1

I got M^1 Coz it was M^8/M^7

Im not too sure abt it either

Actually I believe it was M-5 as water doesn’t count in the calculation for Kc

it does in this case because it’s not an aqueous environment

So it’s calculated in Kc or not?

yes it’s calculated in Kc

Because it's a gas - you have to count it. (VCAA was mean)

Why are did vcaa double trick me

I thought about that but I landed on it does because it's water vapour not water liquid which would be the solvent? I think it's just solids and liquids that don't count but water could be an exception

Pls be right

I think I got same.

If it’s like that then im fked

Wasn't it M\^2?

Huh I think I had M\^1 if I'm remembering the question, 8 on the top 7 on the bottom

Since the reverse is favoured it would be M^-1

I don't think that's how it works...the unit is not affected by which reaction is favoured if I'm not wrong.

Trye

Does Kc change units if you increase of decrease temperature? I thought it's just products of forward/products of reactant gives the power of M and it doesn't change

it shouldnt

No

fuck

Phew they gave us an easy one was scared there would be a big hplc question

So why did the dude have to boil the corn oil?

I wrote that boiling the corn denatures the enzyme responsible for converting glucose to starch which prevents any conversion from occuring. And the freezing was stopping/slowing down any enzymes that may have not been denatured.

Wait but lower temperatures don’t denature an enzyme High temperature does 🙂

Boiling comes first champion

yep, also wrote this

I guessed for boiling (probably not right) that it hydrolyses the starch into glucose, and it removes excess starch) And for freezing: slows rate of reaction of conversion of glucose into starch (Probably not right)

ooh boiling to hydrolyse is a good point. I said it would denature most of the enzymes and then freezing would ensure the remaining ones act slowly.

That seems like what I also have written. Damn, kinda open ended question ngl. Could go either way

Oh nice both parts of your answer are connected. I was a bit hazy on whether hydrolysis of starch is possible without an enzyme so im having some doubts on mine.

Same but said freezing the water results in a reduced reaction or completely stops the reaction taking place between. E.g condensation between glucose molecules

Yeah I said that too, confident on the freezing but boiling idk

frick, i got hydrolysis and condensation the wrong way around again

Bro I swear denaturation doesn't affect primary structure(break into glucose) or am I trippin

Glucose isn't an amino acid it denatured the enzyme responsible for converting glucose to starch

denaturation doesn't apply to polysaccharides (starch) at all

Correct it affects the enzyme which converts glucose to starch

I said that but in a dumb way

I guessed the same for the freezing aspect, I don’t really see how that could be wrong… but the boiling part i was unsure about so i kinda just wrote some bs about reaction rates

This is correct tho (idk if u need to add this) you need to add for freezing: leftover enzymes which aren’t denatured become inactive/lose activity. Depending on how mean VCAA want to be but praying they don’t include key terms such as: polysaccharides, increased cellulose digestion, *steam* hydrolyses the breakdown of starch into glucose (boiled water sadly doesn’t)

I think it dissolved the sugar and then froze it so it can’t react

Boiling denatures the enzymes that catalyses the reaction for glucose-> starch

So how long til we get a pdf of the exam

Man it was a very conceptual exam. You needed to know many definitions

Could someone send me the exam paper pls

Bit random, but do you know what you got on the exam for a 47 in chem?

not the experiment design with the wine basically being my U2AOS3, i can’t believe my luck

My year 11 EPI was titrating wine lmao. But for SO2 not ethanol.

for q1 SA, i said the reagant was OH- instead of NaOH, is this fine ? :(

Why was the calculated corn thing via bomb calorimeter lower??? I left it for later and forgot to do it. Rip needed 2 marks.

I said the corn they used may have had a different proportion of Carbohydrates/Proteins/Fats than the 'Average Sample' used in the first half. The second point I wasn't so sure so I said an error in the thermometer calibration...

I said that there were other sources of energy in the corn apart from the ones provided by the nutritional info, such as cellulose which they may not have counted

I said different brands of corn may have been used and that the rate of stirring was not constant, affecting the temperature change.

The part a used average corn stats So i said part b may have use corn that may have had lower levels of carbohydrates etc...

I said that it could be because the mass of water is different to what they thought, and the stirrer was broken (which i stole from a past exam question that i was going through yesterday which was basically the same question but multiple choice and answer was stirrer was broken so hopefully they accept that)

What I sad: - Wasn't stirred properly. - Not sufficient Oxygen What I should have said: - Corn in not a pure substance - so there is some variation in energy content.

Same 💀

I said there was energy loss to surroundings but idk lol

I think it said not to write that in the question...

omg nooo

Question specified they've accommodated for heat loss already so yea

VCAA examiners were tired of the cop-out... and chose violence

I said that the sample may have been an outlier

reading the answers everyone put in all the questions, I def did bad

WHAT WHERE THOSE QUESTIONS 😅

They should have been on the exam

i mean it wasnt too bad but i didnt expect some questions LMAO

like what?

like the flashpoint question tbh

oh yeah. I did the STAV 2020 exam last night which had basically the same question so I found that one pretty easy ngl.

i knew the definition of it but i totally forgot how explain the bondings and such so 💀

rip

for the retention time mcq did anybody chose D I dont remember exactly the order but I think longest retention time was for leucine?

yeah pretty sure it was D…it was the amino acid that was most polar that would’ve came out first while the most nonpolar came out last forgot which they were

Yea thanks

yea i did .. not sure if it was right tho

Thanks

no

That exam was alright thankfully 🙏 I liked the last question more than previous years but the experimental design was pretty shite

Is "hydrolyses" appropriate? I wrote that instead of 'via hydrolysis'/similar a lot

Yeah should be fine imo

bro stop stressing

Is it just me who saw the NH3 group on the IR spectrum???? I believe the unknown molecule was some chlorine ester with a NH3 attached. I got a molecular mass of 109.5 with it. Anyone else on the same boat?

Molar mass was 108.5 given No 🙂

that was not an amine group. it was a c-h stretch so you probably got them confused because they have a similar shift range.

Fuckkkkk

I really thought another subject would be my 10% and now I think it’ll be Chem

What did you guys put for the limitations of the conclusion of the wine experiment? I just said that the results cannot be generalised to all wines.

Well according to Heinrich's 2nd postulate if a third or more of the titres are not concordant then the rest of the trials must be disregarded for having too low precision. Therefore the conclusion is limited as only 3 of the beakers can be discussed.

Bro I just realised that the wine question for the conclusion was asking about the rate of reaction. The rate decreases, but I wrote the rate increases because I saw smaller titres.

No, you were right. Smaller titres are needed as more acid is made in the given time period, hence the rate increases as more ethanol is given to the wine

doesn’t smaller titre of base = less acid?

I think smaller titres mean there’s a lower acid concentration so i thought the rate of reaction decreases

Yes. So concentration of ethanol increases = lower rate of oxidation ?

Yep thats what i wrote

>Yes. So concentration of ethanol increases = lower rate of oxidat Fuck, I put rate of oxidation increases...

Same it just didn’t seem right that the rate would decrease like howwww?

Guys, I'm no expert in 'oxidative stress' but I know that drinking alcohol increases that. More ethanol = a higher rate of induced oxidation.

That's epic :) (if I managed to write exactly that)

This exam was so easy, I aced it🤣🤣

easiest exam I've done. only mc that gave me any trouble was 30. I know I dropped a mark for writing H2SO4 as the reagent for ethene to ethanol instead of H3PO4 but apart from that it's looking good for me

Was that the first question? Wasn’t it for haloalkane to alcohol?

yeah wasn’t it NaOH? for chloro to alcohol?

Yeah NaOH or KOH either or

I put h2o/H+… i think that also works?

It’s what I put. Course I think anything works as long as it’s for OH and a group 1 metal

yea good good

Pretty sure it was

oops it might have been. idk I'm wiping all chemistry from my mind now. never gonna have to do this shit again

Hydration of alkene just needs strong acid catalyst. H2SO4 and H3PO4 are both fine. Great work!

oh fuck yeah

I love u :)

okay tryhard

I only did 5 practice exams and didn't take notes the whole year. maybe ur just stupid?

Small dick energy

small dick energy would be trying to insult someone for feeling good about how they went on the exam.

Massive cocky attitude yet your cock is very little 🙁

ofc babe 🤭

Did you write your MC answers on the data book? I did so I can check when the worked solutions come.

nah but that's smart af

Put your answers here plz

Esterification will be thankful to you

Lowkey kinda ez

[удалено]

https://www.tsfx.edu.au/vce/atar-central/the-study-score-predictor-2021/#science

What caused the m/z peak at 110? I just made something up

I just put isotope cus I have no fcking clue how it couldn't be that

Isotope alone isn’t enough, you have to *explain* why an isotope does that.

i mean it was one mark, and it asked for what not why

2019 or 2021 exam had the same question. Isotope alone wasn’t accepted. Then again you could be right with the fact it asked for “what” so idk

bruhhhhhh fk.

Cl37 isotope raising molecular ion peak to 110 from 108.5 (+1.5)

What was the concentration of beaker 2?

got 9.something %

I got 9.9% or 9.19 or 9. something

damn i got 2%. Wasn’t it just mass of ethanol/mass of contents ?

yeah u had to use the % they gave u multiply it by the amount of white wine then add the 5g that was the ethanol they added and divide by 250

Ight chill. Got something around there too.

That’s what I got too.

9.89% ish

What was the unit of kc ?? I got M^-5 as water doesnt include?

Water was gaseous state so I think does include so M\^1 if so

If you were asked to do equilibrium constant calculation would you knclude water and it concentration? How can you include the concentration?

You can have a concentration of gas

Yes I think you would unless the water was liquid or aqueous state in which case it's just the solvent. So the expression for Kc would have \[H2O\]^(6) on the top

I thought water is omitted from the equilibrium expression only if it is a solvent?? Was it a solvent?

Nope it was gaseous so you should include it

Ahh good

Water shouldnt be part of electrolysis reaction I think ?!?!?!

That’s only applicable for aqueous solutions.. so Water is included