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August 12, 2022, 12:20:42 am

Author Topic: VCE Chemistry Question Thread  (Read 2005474 times)  Share 

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Chocolatepistachio

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Re: VCE Chemistry Question Thread
« Reply #9285 on: June 15, 2022, 09:43:50 pm »
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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

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Re: VCE Chemistry Question Thread
« Reply #9286 on: June 21, 2022, 04:04:21 pm »
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What are the disadvantages of step wise elution over other elution methods 

beep boop

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Re: VCE Chemistry Question Thread
« Reply #9287 on: June 29, 2022, 09:23:18 pm »
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Hi All,

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

Much appreciated,
beep boop
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Billuminati

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Re: VCE Chemistry Question Thread
« Reply #9288 on: June 29, 2022, 10:34:54 pm »
+2
Hi All,

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

Much appreciated,
beep boop

You should be developing your reasoning of errors since they're asked so frequently by VCAA.
VCE 2016-2018

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

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Chocolatepistachio

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Re: VCE Chemistry Question Thread
« Reply #9289 on: July 02, 2022, 07:20:39 pm »
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Can someone explain capillary electrophoresis and what the disadvantages are

Billuminati

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Re: VCE Chemistry Question Thread
« Reply #9290 on: July 02, 2022, 08:34:19 pm »
+3
Can someone explain capillary electrophoresis and what the disadvantages are

You'd probably have to take 3rd year analytical chem to know this, this wasn't even taught in 2nd year analytical which is the limit of my knowledge. From its name, it sounds like some kind of separation ie chromatographic technique
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

Chocolatepistachio

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Re: VCE Chemistry Question Thread
« Reply #9291 on: July 03, 2022, 09:06:50 pm »
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What are the benefits of solvent trapping when using splitless injection mode

Bri MT

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Re: VCE Chemistry Question Thread
« Reply #9292 on: July 07, 2022, 09:52:06 pm »
+2
What are the benefits of solvent trapping when using splitless injection mode

Heyo, this is well beyond the scope of VCE chemistry. I know it's quieter, but questions like this would be more suited for the university section (and many of us check recently unread rather than checking individual threads anyway).

Chocolatepistachio

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Re: VCE Chemistry Question Thread
« Reply #9293 on: July 19, 2022, 09:06:00 pm »
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For this question why is it less than 5.14
If the stationary phase is more polar then wouldn't it interact more and the retention time increases
polarity of the mobile phase decreases then the polar compound has a lower affinity for the mobile phase so longer retention time

Billuminati

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Re: VCE Chemistry Question Thread
« Reply #9294 on: July 21, 2022, 09:11:10 pm »
+1
For this question why is it less than 5.14
If the stationary phase is more polar then wouldn't it interact more and the retention time increases
polarity of the mobile phase decreases then the polar compound has a lower affinity for the mobile phase so longer retention time

A H2O/acetonitrile mobile phase already indicates a reverse phase chromatographic technique since the mobile phase is polar, implying that the stationary phase and analytes ie ketamine will be relatively non polar. No idea why they said "if the chromatography was reverse phase" as if it wasn't RP-HPLC already.

100% acetonitrile is also polar, but less so than 50% H2O and 50% acetonitrile. Hence ketamine which is implied to be more non polar will elute faster cuz it spends more time in the 100% acetonitrile mobile phase compared to 50% H2O and 50% acetonitrile following the like dissolves like rule. BTW ketamine ain't aliphatic cuz it has a benzene ring, so I don't know what kind of crack the question is on
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