Login

Welcome, Guest. Please login or register.

March 29, 2024, 05:40:53 am

Author Topic: VCE Chemistry Question Thread  (Read 2313335 times)  Share 

0 Members and 5 Guests are viewing this topic.

EllingtonFeint

  • Trendsetter
  • **
  • Posts: 153
  • Offering private tutoring ✨
  • Respect: +24
Re: VCE Chemistry Question Thread
« Reply #8205 on: October 22, 2019, 03:18:07 pm »
0
Did you read the first part of the question?

Yeah, but I still don't understand it!  :-[
Biology 🌱 [49] |  English [47]

Surviving and Succeeding in Biology:
https://atarnotes.com/forum/index.php?topic=187145.msg1129188

Erutepa

  • VIC MVP - 2019
  • Forum Leader
  • ****
  • Posts: 721
  • evenin'
  • Respect: +775
Re: VCE Chemistry Question Thread
« Reply #8206 on: October 24, 2019, 07:51:05 am »
+4

Yeah, so that's what I was thinking, but the answer is actually C (I probably should have said that at the start)...
This is what the examiner's report said:

Linking the electrochemical series data
O2(g) + 4H+(aq) + 4e– → 2 H2O(l) E0 = +1.23 V
VO2+(aq) + 2H+(aq) + e– → VO2+(aq) + H2O(l) E0 = +1.00 V
VO2+(aq) + 2H+(aq) + e– → V3+(aq) + H2O(l) E0 = +0.34 V
V3+(aq) + e– → V2+(aq) E0 = –0.26 V
The strongest reductant, V2+(aq), is oxidised to V3+(aq), which is both an oxidant and a reductant.
Subsequently as the [V2+(aq)] decreases, the next strongest reductant, V3+(aq), is oxidised to VO2+(aq) by O2.
If the reaction is allowed to continue, since VO2+(aq) is also both an oxidant and a reductant, VO2+(aq) can be oxidised to VO2+(aq) by O2(g).
So V2+(aq) can be oxidised to V3+(aq), VO2+(aq) and VO2+(aq).


I could not make sense of any of that

(I definitely think it's a weird question  :-\)
This answer is a bit odd, but
What this answer is saying is that V2+ is the strongest reductant which means it will be oxidised first. After all the V2+ is oxidised, the next strongest reductant will be oxidised (in this case V3+).
You can determine the strongest reductant by constructing an electrochemical series by listing all the possible half cell reactions from the greatest resultant voltage to the lowest. Species on the right side of the equation are reductants and increase in strength as you move further down the electrochemical series. Species on the left side of the equation are oxidants and increase in strength as you move further up the electrochemical series
I assume there was more information given in a question stem above that applied to the question, hence the 4 half cell equations provided in the answer guide.
Qualifications
 > Have counted to 227
 > Can draw really good spiders
 > 2 Poet points
 > 6.5 insanipi points
 > 1 Bri MT point

colline

  • MOTM: NOV 19
  • Forum Obsessive
  • ***
  • Posts: 341
  • ♡ 2 Timothy 1:7 ♡
  • Respect: +512
Re: VCE Chemistry Question Thread
« Reply #8207 on: October 24, 2019, 10:47:01 pm »
0
Am I right in automatically assuming that there is NO independent variable present when performing a titration? Or should we always assume that the sample of solution is not uniform?
(VCAA 2017 Q9a)

Thanks.

VCE: Literature [50] Methods [50] Further [48] Chemistry [40] Biology [33]
2022: Bachelor of Science (Mathematical Economics) @ ANU

jinaede1342

  • Forum Regular
  • **
  • Posts: 75
  • Respect: +34
Re: VCE Chemistry Question Thread
« Reply #8208 on: October 25, 2019, 01:50:23 pm »
0
Just came across a question in the VCAA 2011 Exam 2 paper

Section B Question 6. its about equilibrium which I know is still relevant to the course. But does anyone know if this is really assumed knowledge? it asks to determine the concentration fo H3O+ ions and subsequently the pH etc. I've only come across this content in year 11 and never with this degree of difficulty.... so long story short, can we expect questions like this in the real exam?

edit: no titration is involved (thats how confused I am at this point)
« Last Edit: October 25, 2019, 01:58:08 pm by jinaede1342 »
VCE: | English [48] | Global Politics [44] | Biology [40] | Chemistry [36] | French [34] | Methods [32]
ATAR: 98.40
2020: Bachelor of Laws (honours)/ Bachelor of Commerce @ Monash

Selling Global Politics responses + English/Global feedback and essay correction: https://atarnotes.com/forum/index.php?topic=189680.0

Global Politics Tuition via Zoom - PM for details

sweetcheeks

  • Forum Obsessive
  • ***
  • Posts: 496
  • Respect: +83
  • School: ---
  • School Grad Year: 2016
Re: VCE Chemistry Question Thread
« Reply #8209 on: October 25, 2019, 02:34:31 pm »
+1
Just came across a question in the VCAA 2011 Exam 2 paper

Section B Question 6. its about equilibrium which I know is still relevant to the course. But does anyone know if this is really assumed knowledge? it asks to determine the concentration fo H3O+ ions and subsequently the pH etc. I've only come across this content in year 11 and never with this degree of difficulty.... so long story short, can we expect questions like this in the real exam?

edit: no titration is involved (thats how confused I am at this point)

Weak acid and bases has been removed from the study design. This question is much more straightforward when you learn the topic (its a really simple pH buffer question, once you know about those systems). You won't see this type of question on the exam.

hums_student

  • MOTM: SEP 18
  • Forum Obsessive
  • ***
  • Posts: 379
  • Respect: +520
Re: VCE Chemistry Question Thread
« Reply #8210 on: October 25, 2019, 03:30:06 pm »
+2
Am I right in automatically assuming that there is NO independent variable present when performing a titration? Or should we always assume that the sample of solution is not uniform?
(VCAA 2017 Q9a)

Thanks.

Unless the question gives more specific info about the experiment, both would be considered equally correct by VCAA.
2019-21: Bachelor of Arts (Politics & Int'l Relations / Economics)

-_-zzz

  • Trailblazer
  • *
  • Posts: 26
  • Respect: 0
Re: VCE Chemistry Question Thread
« Reply #8211 on: October 28, 2019, 07:00:45 pm »
+1
Am I right in automatically assuming that there is NO independent variable present when performing a titration? Or should we always assume that the sample of solution is not uniform?
(VCAA 2017 Q9a)

Thanks.

Quite frankly I don't think there is an independent variable at all and hence I disagree with the examiner's report. This is because while the chemical composition of each tartaric acid sample may indeed be different, it isn't a factor that you are deliberately altering in order to test its effect on a dependent variable. Hope this makes sense.

KiNSKi01

  • Forum Obsessive
  • ***
  • Posts: 267
  • Respect: +9
Re: VCE Chemistry Question Thread
« Reply #8212 on: October 28, 2019, 07:22:35 pm »
+1
Quite frankly I don't think there is an independent variable at all and hence I disagree with the examiner's report. This is because while the chemical composition of each tartaric acid sample may indeed be different, it isn't a factor that you are deliberately altering in order to test its effect on a dependent variable. Hope this makes sense.

According to my teacher, students who said there was no independent variable still received marks for that question for the reasons mentioned

Not sure why that wasn't included in examiners report but hopefully that alleviates any concerns
ATAR: 98.20

'18:
Physics - 42
Psychology - 40

'19:
English Language -42
Chemistry - 40
Further Maths - 45
Maths Methods - 40

AnonymooseUser

  • Trailblazer
  • *
  • Posts: 30
  • Respect: 0
Re: VCE Chemistry Question Thread
« Reply #8213 on: October 31, 2019, 02:58:30 pm »
0
Is it true that if we are given a volume of water in a heat energy question, we have to multiply it by its density before doing any calculations rather than just a 1:1 conversion to grams?

sweetcheeks

  • Forum Obsessive
  • ***
  • Posts: 496
  • Respect: +83
  • School: ---
  • School Grad Year: 2016
Re: VCE Chemistry Question Thread
« Reply #8214 on: October 31, 2019, 03:22:16 pm »
+1
Is it true that if we are given a volume of water in a heat energy question, we have to multiply it by its density before doing any calculations rather than just a 1:1 conversion to grams?

Yes, you will be expected to do the density conversion. You are given the density of water at 25˚C in the data booklet.

AnonymooseUser

  • Trailblazer
  • *
  • Posts: 30
  • Respect: 0
Re: VCE Chemistry Question Thread
« Reply #8215 on: October 31, 2019, 03:59:21 pm »
0
Yes, you will be expected to do the density conversion. You are given the density of water at 25˚C in the data booklet.

Yep, just wanted to make sure. Thank you!

3086

  • Forum Regular
  • **
  • Posts: 64
  • Respect: +35
Re: VCE Chemistry Question Thread
« Reply #8216 on: October 31, 2019, 09:14:14 pm »
0
Does anyone have any practice exams?
2019 (Goals) ATAR: 93.00
Physics [44] Chemistry [40] Biology [40] English [35] Methods [25]

Bri MT

  • VIC MVP - 2018
  • Administrator
  • ATAR Notes Legend
  • *****
  • Posts: 4719
  • invest in wellbeing so it can invest in you
  • Respect: +3677
Re: VCE Chemistry Question Thread
« Reply #8217 on: October 31, 2019, 09:18:44 pm »
+1
Does anyone have any practice exams?

Hey, sharing or requesting copyrighted material isn't allowed on atarnotes. There is a free atarnotes practice exam for chem and I'd recommend you do and redo the relevant VCAA practice exams

rani_b

  • Trendsetter
  • **
  • Posts: 168
  • Respect: +67
Re: VCE Chemistry Question Thread
« Reply #8218 on: November 02, 2019, 09:34:16 am »
0
Hey guys,

when turning ethene into ethane, what is the catalyst used in what state?
Also, to what extent do we need to know about monomers and polymers?

Thanks!
2019 ATAR: 99.85

Selling: English [50] & Lit [48] essays! PM for details.

sweetiepi

  • National Moderator
  • ATAR Notes Legend
  • *****
  • Posts: 4767
  • "A Bit of Chaos" (she/they)
  • Respect: +3589
Re: VCE Chemistry Question Thread
« Reply #8219 on: November 02, 2019, 11:13:31 am »
+1
Hey guys,

when turning ethene into ethane, what is the catalyst used in what state?
The catalyst that is commonly used is solid Nickel! ^-^

I'm not entirely sure what is covered explicitly for monomers and polymers, however, best to look at the VCAA study design for guidance! :)
2017-2019: Bachelor of Pharmaceutical Science (Formulation Science)
2020: Bachelor of Pharmaceutical Science (Honours) Read my uni journey here!