Login

Welcome, Guest. Please login or register.

March 29, 2024, 08:12:27 am

Author Topic: VCE Chemistry Question Thread  (Read 2313401 times)  Share 

0 Members and 1 Guest are viewing this topic.

TnGn74

  • Adventurer
  • *
  • Posts: 7
  • Respect: 0
Re: VCE Chemistry Question Thread
« Reply #9270 on: March 14, 2022, 06:20:51 pm »
+1
Hey, for combustion reactions and thermochemical equations I was wondering if you give the state of water as (l) or (g)? The answers seem to be inconsistent (for the combustion of octane one gives it as liquid while the other gives it as solid)

Thanks!

I would give H2O(g) for combustion reactions (because hot) in general. Give H2O(l) if it states a specific temperature <373K or SLC, and that includes when giving a dH from the data book in a thermochemical equation as those values are at SLC.
« Last Edit: March 14, 2022, 07:40:15 pm by TnGn74 »

Arad S

  • Fresh Poster
  • *
  • Posts: 1
  • Respect: 0
Re: VCE Chemistry Question Thread
« Reply #9271 on: March 15, 2022, 10:48:47 am »
0
Hello guys, can anybody help me for writing an aim for an experiment?

This experiment is about the galvanic cell, which there is 6 half cell with 50 ml of their solutions, which we need to determine the voltage produce by each electrochemical cell and determining that which rod is oxidation or reduction.

Thanks!

biology1234

  • Forum Regular
  • **
  • Posts: 84
  • Respect: 0
Re: VCE Chemistry Question Thread
« Reply #9272 on: March 21, 2022, 04:13:22 pm »
0
Why are ionic substances brittle? Thanks

bw304

  • Trailblazer
  • *
  • Posts: 33
  • Respect: +18
Re: VCE Chemistry Question Thread
« Reply #9273 on: April 02, 2022, 01:29:18 pm »
0
hi all, could i have some help with this electrolysis question?

An electrolytic cell was constructed using a sodium chloride solution for the electrolyte, a copper electrode and a zinc electrode. Complete the reduction half-equation, oxidation half-equation and overall equation.

based off the electrochemical series i got:

Reduction half-equation: 2H2O(l) + 2e- --> H2 (g) + 2OH-aq
Oxidation half-equation: Zn(s) --> Zn2+(aq) + 2e-
Overall equation: 2H2O(l) + Zn(s) --> H2 (g) + 2OH-aq + Zn2+(aq)

however the solutions say:

Reduction half-equation: 2H2O(l) + 2e- --> H2 (g) + OH-aq
Oxidation half-equation: Zn(s) --> Zn2+(aq) + 2e-
Overall equation: H2O(l) + Zn(s) --> H2 (g) + Zn2+(aq)

i think there's a balancing error in the solutions for the reduction equation? i'm mainly confused to how they've balanced the final reaction. how come the OH- disappears without any H+ ions being added?
any help would be appreciated!

2021 | psychology |
2022 | english | methods | specialist | biology | chemistry |

user28

  • Fresh Poster
  • *
  • Posts: 3
  • Respect: 0
Re: VCE Chemistry Question Thread
« Reply #9274 on: April 02, 2022, 05:23:16 pm »
0
Do Sac marks really matter?

Hello, I was wondering if getting a 40% on my chemistry SACs will impact my study score. Should I be worried about these marks?

I want to aim higher but the content is quite difficult at the moment. What's the mark that I should be aiming for to get a decent study score?

Thanks !

lm21074

  • MOTM: JAN 19
  • Victorian Moderator
  • Forum Leader
  • *****
  • Posts: 589
  • Respect: +594
Re: VCE Chemistry Question Thread
« Reply #9275 on: April 02, 2022, 09:00:04 pm »
+5
Why are ionic substances brittle? Thanks
When you apply pressure to an ionic substance, the alignment of the ions change and they often move closer together. When ions with like charges move closer together, there is an electrostatic repulsion between them causing the structure to shatter.

hi all, could i have some help with this electrolysis question?

An electrolytic cell was constructed using a sodium chloride solution for the electrolyte, a copper electrode and a zinc electrode. Complete the reduction half-equation, oxidation half-equation and overall equation.

based off the electrochemical series i got:

Reduction half-equation: 2H2O(l) + 2e- --> H2 (g) + 2OH-aq
Oxidation half-equation: Zn(s) --> Zn2+(aq) + 2e-
Overall equation: 2H2O(l) + Zn(s) --> H2 (g) + 2OH-aq + Zn2+(aq)

however the solutions say:

Reduction half-equation: 2H2O(l) + 2e- --> H2 (g) + OH-aq
Oxidation half-equation: Zn(s) --> Zn2+(aq) + 2e-
Overall equation: H2O(l) + Zn(s) --> H2 (g) + Zn2+(aq)

i think there's a balancing error in the solutions for the reduction equation? i'm mainly confused to how they've balanced the final reaction. how come the OH- disappears without any H+ ions being added?
any help would be appreciated!


I think the solution would be wrong here. What you've done looks right and I too don't understand why they would remove the hydroxide ion from the final equation. It doesn't seem to be a spectator ion.

Do Sac marks really matter?

Hello, I was wondering if getting a 40% on my chemistry SACs will impact my study score. Should I be worried about these marks?

I want to aim higher but the content is quite difficult at the moment. What's the mark that I should be aiming for to get a decent study score?

Thanks !
I would say yes and no. In short, it's a bit difficult to predict what sort of scores can lead to what study scores. Your SAC marks are moderated so your raw SAC marks don't often end up being your final SAC marks used in the calculation of your study score. A 65 at one school can get scaled up to an A+, and stay the same at another due to factors outside of your control, like how difficult your SACs are. It also depends on what sort of study score you're aiming for. The score that I got in chem was decent to me considering all that happened last year, but for some people, they wouldn't be happy with that study score. If we're looking towards getting the usual prereq score of 25, I reckon you'll be able to based on what you've said. It's one SAC so in essence, it shouldn't impact your study score too much. Keep asking for help and most likely you'll see an improvement in your marks. This is something I wish I did more, especially during the later parts of the year.

HELPPPP!!!!
I DONT GET MOLES/RELATIVE ATOMIC MASS/EVERYTHINGGGGGG

I CANT SEEM TO GRASP THE CONCEPT AT ALL

I don't get N vs n vs m vs M
I need a review over everything
Hi there,


Are you doing Units 1&2 atm? I'm asking just to know in what contexts you would be applying this theory.

Regardless of what year level you're in, I've linked this video on mole calculations (it's a bit long albeit useful) and this video on relative atomic mass which might help you consolidate these concepts. If you have any specific questions, let us know.
Hello guys, can anybody help me for writing an aim for an experiment?

This experiment is about the galvanic cell, which there is 6 half cell with 50 ml of their solutions, which we need to determine the voltage produce by each electrochemical cell and determining that which rod is oxidation or reduction.

Thanks!
The aim should include an action verb like investigate, perform, or explore, your independent variable(s), and dependent variable(s). I would say that the last sentence you've got there in describing the experiment is a pretty decent aim ;).
« Last Edit: April 02, 2022, 09:29:59 pm by lm21074 »
2021: VCE
2022: Science / Arts @ Monash

biology1234

  • Forum Regular
  • **
  • Posts: 84
  • Respect: 0
Re: VCE Chemistry Question Thread
« Reply #9276 on: May 15, 2022, 02:10:23 pm »
0
hey, if covalent bond is polar does that make it automatically dipole-dipole interactions/ bonding. For example, ICI how do we know that it uses dipole-dipole forces. Thanks hope that question makes sense.

biology1234

  • Forum Regular
  • **
  • Posts: 84
  • Respect: 0
Re: VCE Chemistry Question Thread
« Reply #9277 on: June 09, 2022, 12:41:08 pm »
0
hey,
how do you work this question out easily
thank you
ASAP

lm21074

  • MOTM: JAN 19
  • Victorian Moderator
  • Forum Leader
  • *****
  • Posts: 589
  • Respect: +594
Re: VCE Chemistry Question Thread
« Reply #9278 on: June 09, 2022, 08:22:58 pm »
+1
hey,
how do you work this question out easily
thank you
ASAP
Look at the size of the molecule and what it contains.

Longer hydrocarbon chains would be less soluble in water than shorter ones due to the dispersion forces between molecules.

Molecules with hydroxyl groups tend to be more soluble in water too due to the formation of intermolecular hydrogen bonds.
hey, if covalent bond is polar does that make it automatically dipole-dipole interactions/ bonding. For example, ICI how do we know that it uses dipole-dipole forces. Thanks hope that question makes sense.
Yep, polar covalent bonds would have a dipole because there is unequal sharing of electrons.
« Last Edit: June 09, 2022, 08:30:56 pm by lm21074 »
2021: VCE
2022: Science / Arts @ Monash

Chocolatepistachio

  • Science Games: Silver
  • Forum Obsessive
  • ***
  • Posts: 470
  • Respect: +51
Re: VCE Chemistry Question Thread
« Reply #9279 on: June 14, 2022, 07:43:25 pm »
0
Can someone explain the process of atomic absorption spectroscopy and
explain why separation of the ions is not required when analysing by AAS

Billuminati

  • Science Games: Gold
  • Forum Obsessive
  • ***
  • Posts: 300
  • Respect: +127
Re: VCE Chemistry Question Thread
« Reply #9280 on: June 14, 2022, 07:52:14 pm »
+2
Can someone explain the process of atomic absorption spectroscopy and
explain why separation of the ions is not required when analysing by AAS

AAS involves a lamp containing the element you want to quantify emitting light of the same wavelength of absorption as your sample, this light source is shined onto a high temperature burner which converts the element of interest in your sample into gaseous, ground state atoms which can absorb this electromagnetic radiation. This absorbance is detected by computers, but not before being wavelength-restricted to the intended wavelength by a monochromator to increase signal:noise ratio. You don't need to separate the species since each ion absorbs a specific wavelength of electromagnetic radiation so there's rarely any interference between 2 different analytes which may cause overestimation of concentration. It's thanks to the fact that all e- transitions are quantised so each transition in different species is represented by a very specific spectral line. Remember that ions are NOT appropriate for AAS since ions have different spectral lines to ground state atoms. You can still analyse ion concentrations in a solution with AAS but they have to be converted to ground state atoms by the burner
« Last Edit: June 14, 2022, 07:59:31 pm by Billuminati »
VCE 2016-2018

2017: Biology [38], Further Maths [44]

2018: Methods [37], French [38], Chem [40], English [44]

UMAT: 56/43/80, 57th percentile (LLLLOOOOOOOOOLLLLLLLL)

ATAR: 98.1

2019-2021: Bachelor of Biomedical Science at Monash (Scholars), minoring in Chemistry

GAMSAT September 2021: 65/67/86, 76 overall (98th percentile)

2022: Chilling

2023+: Transfer to teaching degree

ThomasK12

  • Fresh Poster
  • *
  • Posts: 1
  • Respect: 0
Re: VCE Chemistry Question Thread
« Reply #9281 on: June 15, 2022, 12:38:29 pm »
0
Heyy,
If someone has the 2015 TSSM organic chemistry (polymers) key topic test can u plss send??
Thankss

Chocolatepistachio

  • Science Games: Silver
  • Forum Obsessive
  • ***
  • Posts: 470
  • Respect: +51
Re: VCE Chemistry Question Thread
« Reply #9282 on: June 15, 2022, 09:43:50 pm »
0
Can someone explain the standard addition method and the difference between the standard addition method and use of a calibration curve and calibration standards 

Chocolatepistachio

  • Science Games: Silver
  • Forum Obsessive
  • ***
  • Posts: 470
  • Respect: +51
Re: VCE Chemistry Question Thread
« Reply #9283 on: June 21, 2022, 04:04:21 pm »
0
What are the disadvantages of step wise elution over other elution methods 

beep boop

  • Trendsetter
  • **
  • Posts: 114
  • studying, what is that?
  • Respect: +45
Re: VCE Chemistry Question Thread
« Reply #9284 on: June 29, 2022, 09:23:18 pm »
0
Hi All,

Can someone please help me w/ q13 c and q15d?

Much appreciated,
beep boop
class of '22
'21: viet sl [36], bio
'22: psych, methods, spesh, chem, eng lang
"Distance makes the heart grow fonder and proximity makes the heart want to barf."-Mr K, Never have I Ever
yr 12 stuff :)