• We need YOU to help the next generation of students in the community for the new syllabus!
    Share your notes and trial papers on our Notes & Resources page
  • Like us on facebook here

HSC Chemistry Exam Solutions / Thoughts (1 Viewer)

flowerp

Member
Joined
May 15, 2017
Messages
115
Gender
Undisclosed
HSC
N/A
For the last q. I also said that via a substitution reaction with NaOH we can get ethanol, but I also forgot to include the conditions ugghhhh! Hope we don't lose marks!!! I've already lost 10 marks for sure ... and really want a b6 uugghhh the sheer amount of silly mistakes I make in EVERY EXAM is ridiculous!
 

CarbonMini

New Member
Joined
Aug 29, 2017
Messages
19
Gender
Male
HSC
2019
For the last q. I also said that via a substitution reaction with NaOH we can get ethanol, but I also forgot to include the conditions ugghhhh! Hope we don't lose marks!!! I've already lost 10 marks for sure ... and really want a b6 uugghhh the sheer amount of silly mistakes I make in EVERY EXAM is ridiculous!
I mean as @Arrowshaft has mentioned above u only apparently need NaOH with no other conditions? IDK, im pretty sure you need heat, Ill check my textbook in the morning
 

flowerp

Member
Joined
May 15, 2017
Messages
115
Gender
Undisclosed
HSC
N/A
So I just googled, apparently primary haloalkanes require a catalyst with NaOH due to the slow reaction which occurs, and reflux conditions can be used :( :(
 

CarbonMini

New Member
Joined
Aug 29, 2017
Messages
19
Gender
Male
HSC
2019
So I just googled, apparently primary haloalkanes require a catalyst with NaOH due to the slow reaction which occurs, and reflux conditions can be used :( :(
Oh shoot I mean its a 7 marker so hopefully what u wrote was enough??? Im starting to get worried because I only wrote heat, not reflux...
 

Arrowshaft

Well-Known Member
Joined
Sep 2, 2018
Messages
559
Location
NSW
Gender
Male
HSC
2019
I’m sure it’ll be fine, max we could lose is 1 mark anyway. also if our other info is coherent enough it should be fine and we might mot lose a mark
 

Jendeukie

Member
Joined
Dec 6, 2016
Messages
30
Gender
Female
HSC
N/A
so lol...
that difluoro question in the multiple choice? how many carbons in the molecule? anyone sure of their answer for that? only 2 numbers i remember are 750 and 1500
 

Arrowshaft

Well-Known Member
Joined
Sep 2, 2018
Messages
559
Location
NSW
Gender
Male
HSC
2019
so lol...
that difluoro question in the multiple choice? how many carbons in the molecule? anyone sure of their answer from that? only 2 numbers i remember are 750 and 1500
1500? cant rrally rmber
 

Arrowshaft

Well-Known Member
Joined
Sep 2, 2018
Messages
559
Location
NSW
Gender
Male
HSC
2019
Yeah think it was. I just remember i multiplied some number by 2, i think i got 1500
 

Jendeukie

Member
Joined
Dec 6, 2016
Messages
30
Gender
Female
HSC
N/A
1500? cant rrally rmber
OKAY haha i got that too
can't remember all the other MC i felt were sucky so guess i'll have to live in suspense until december 16th

last thing - i remember in the very first q they were asking for a test to differentiate between the aldehyde and the ketone lol... vaguely remembered tollens' reagent and how aldehyde reduces silver ions to silver, but ultimately had no idea what the actual reaction equation was. hope they don't penalise me.
 

Arrowshaft

Well-Known Member
Joined
Sep 2, 2018
Messages
559
Location
NSW
Gender
Male
HSC
2019
OKAY haha i got that too
can't remember all the other MC i felt were sucky so guess i'll have to live in suspense until december 16th

last thing - i remember in the very first q they were asking for a test to differentiate between the aldehyde and the ketone lol... vaguely remembered tollens' reagent and how aldehyde reduces silver ions to silver, but ultimately had no idea what the actual reaction equation was. hope they don't penalise me.
either oxidation with potassium dichromate, aldehyde shiuld change colour from orange to green when oxidised to an acid. After to confirm solid na2co3 can be dissolved producing bubble and u know the rest
 

Jendeukie

Member
Joined
Dec 6, 2016
Messages
30
Gender
Female
HSC
N/A
either oxidation with potassium dichromate, aldehyde shiuld change colour from orange to green when oxidised to an acid. After to confirm solid na2co3 can be dissolved producing bubble and u know the rest
omg i can't believe it yes that's such an obvious thing! i'm so dumb hahaha i got caught up in the silver mirror whatever. like, aldehyde reduces the ions to silver and ketone remains unreactive. now that i think about it, i wouldn't be writing equations for that either so hope they don't penalise

thanks bro and gl on your future exams!
 

Arrowshaft

Well-Known Member
Joined
Sep 2, 2018
Messages
559
Location
NSW
Gender
Male
HSC
2019
omg i can't believe it yes that's such an obvious thing! i'm so dumb hahaha i got caught up in the silver mirror whatever. like, aldehyde reduces the ions to silver and ketone remains unreactive. now that i think about it, i wouldn't be writing equations for that either so hope they don't penalise

thanks bro and gl on your future exams!
Thanks, you too (if you have any :p)
 

CarbonMini

New Member
Joined
Aug 29, 2017
Messages
19
Gender
Male
HSC
2019
OKAY haha i got that too
can't remember all the other MC i felt were sucky so guess i'll have to live in suspense until december 16th

last thing - i remember in the very first q they were asking for a test to differentiate between the aldehyde and the ketone lol... vaguely remembered tollens' reagent and how aldehyde reduces silver ions to silver, but ultimately had no idea what the actual reaction equation was. hope they don't penalise me.
I lost like 3 marks in MC - the strong acid strong base, radioactive one and q20...
Though I did well in short answer so yeah... Honestly found MC to be the hardest part of the test
 

lalajellyjoy

New Member
Joined
Jan 13, 2019
Messages
13
Gender
Undisclosed
HSC
2019
I remember specifically adjusting my answer to clearly outline each compound as it said something like 'identify the reagents in each reaction'.
But identifying the reagents didny mean the
I remember specifically adjusting my answer to clearly outline each compound as it said something like 'identify the reagents in each reaction'.
I thought identifying reagents was what was needed for the reaction to occur?? Is that not right?
 

Idkwhattoput

Member
Joined
Mar 14, 2018
Messages
93
Gender
Male
HSC
2019
Uni Grad
2024
But identifying the reagents didny mean the

I thought identifying reagents was what was needed for the reaction to occur?? Is that not right?
I'm as surprised as you. I always thought reagents was synonymous with reactants. Also, for that last question (chloroethane to ethanol), is water and sulfuric acid catalyst correct?? I wrote that but I assumed it was wrong because I can't seem to find them anywhere???
 

Users Who Are Viewing This Thread (Users: 0, Guests: 1)

Top