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December 09, 2019, 06:00:12 pm

Author Topic: VCE Chemistry Exam - 12/11/19 - Discussion/Questions/Solutions  (Read 4874 times)

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Ali Ali

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Re: VCE Chemistry Exam - 12/11/19 - Discussion/Questions/Solutions
« Reply #30 on: November 12, 2019, 05:16:42 pm »
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exam was most definitely longer than previous years though.I could usually finish most exams with 20-30 mins left but this one i had about 20-25 marks completely unanswered before time ran out

Kyokushinkai

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Re: VCE Chemistry Exam - 12/11/19 - Discussion/Questions/Solutions
« Reply #31 on: November 12, 2019, 05:18:24 pm »
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Could anyone tell me if Iím right:

For the concentration time graph we had to draw, I drew all species as decreasing in concentration. My reasoning was that since AgNO3 was added, it would dissociate into Ag+ and NO3- and the NO3- ions would react with the CoCl4+ (or whatever it was) and Co2+, while the Ag+ ions would react with the Cl-, thus drecreasing the concentration of all species.

Sai Ramishetty

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Re: VCE Chemistry Exam - 12/11/19 - Discussion/Questions/Solutions
« Reply #32 on: November 12, 2019, 05:38:56 pm »
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Could anyone tell me if Iím right:

For the concentration time graph we had to draw, I drew all species as decreasing in concentration. My reasoning was that since AgNO3 was added, it would dissociate into Ag+ and NO3- and the NO3- ions would react with the CoCl4+ (or whatever it was) and Co2+, while the Ag+ ions would react with the Cl-, thus drecreasing the concentration of all species.
There was a similar question like this on the NHT 2019 exam question 7. According to the examination report, only the concentration of Cl^-1 is reduced when AgNO3 is added to the equilibrium system. The NO3- does not make any difference as they do not say it reacts with the other positive ion. Please refer the NHT examination report for complete details.

tubbc

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Re: VCE Chemistry Exam - 12/11/19 - Discussion/Questions/Solutions
« Reply #33 on: November 12, 2019, 05:40:14 pm »
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Anyone have solutions to multiple choice?

3086

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Re: VCE Chemistry Exam - 12/11/19 - Discussion/Questions/Solutions
« Reply #34 on: November 12, 2019, 05:56:57 pm »
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Cl- concentration sharply decreased, and as it reached equilibrium Co2+ went up by 1x Cl- went up by 4x, [CoCl4]2- went down by 1x

That's what I did, however, shouldn't all decrease as you are adding a compound that sort of acts like an inert compound so should all go down and then increase.
2019 (Goals) ATAR: 93.00
Physics [44] Chemistry [40] Biology [40] English [35] Methods [25]

3086

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Re: VCE Chemistry Exam - 12/11/19 - Discussion/Questions/Solutions
« Reply #35 on: November 12, 2019, 06:00:37 pm »
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There was a similar question like this on the NHT 2019 exam question 7. According to the examination report, only the concentration of Cl^-1 is reduced when AgNO3 is added to the equilibrium system. The NO3- does not make any difference as they do not say it reacts with the other positive ion. Please refer the NHT examination report for complete details.

But if it reacts with Cl then should its concentration decrease and then increase as the system establishes equilibrium?
2019 (Goals) ATAR: 93.00
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Sai Ramishetty

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Re: VCE Chemistry Exam - 12/11/19 - Discussion/Questions/Solutions
« Reply #36 on: November 12, 2019, 06:01:13 pm »
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That's what I did, however, shouldn't all decrease as you are adding a compound that sort of acts like an inert compound so should all go down and then increase.
No only concentration of Cl- reduces. This was similar to the question in 2019 NHT. Itís question 7. Please do refer examination report. In both questions, there is a positive ion. I am pretty sure both donít react.

Sai Ramishetty

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Re: VCE Chemistry Exam - 12/11/19 - Discussion/Questions/Solutions
« Reply #37 on: November 12, 2019, 06:01:51 pm »
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But if it reacts with Cl then should its concentration decrease and then increase as the system establishes equilibrium?
Yes

Kyokushinkai

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Re: VCE Chemistry Exam - 12/11/19 - Discussion/Questions/Solutions
« Reply #38 on: November 12, 2019, 06:32:55 pm »
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No only concentration of Cl- reduces. This was similar to the question in 2019 NHT. Itís question 7. Please do refer examination report. In both questions, there is a positive ion. I am pretty sure both donít react.

Yeah but if [Cl-] reduces, then also the [[CoCl4]2+] would decrease since the reaction would move forward due to the reduced product concentration.

Matthew_Whelan

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Re: VCE Chemistry Exam - 12/11/19 - Discussion/Questions/Solutions
« Reply #39 on: November 12, 2019, 06:35:46 pm »
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Not that it really matters now but I thought adding an inert molecule would increase the pressure of the system which would favour the reaction that produces less moles.
2018: Psychology
2019: English, Methods, Chemistry, Biology, Physics

tx inspire

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Re: VCE Chemistry Exam - 12/11/19 - Discussion/Questions/Solutions
« Reply #40 on: November 13, 2019, 06:31:15 am »
+1
What was the answer to the fuel blend question? It asked how much energy was released

sk2000

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Re: VCE Chemistry Exam - 12/11/19 - Discussion/Questions/Solutions
« Reply #41 on: November 13, 2019, 07:20:22 am »
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What was the answer to the fuel blend question? It asked how much energy was released

I got something like 3400kj. Not sure if its right but I think I did the calculations correctly.

Anyone know what they got for the grams of sucrose in the soda can?

sk2000

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Re: VCE Chemistry Exam - 12/11/19 - Discussion/Questions/Solutions
« Reply #42 on: November 13, 2019, 07:31:51 am »
+2
Not that it really matters now but I thought adding an inert molecule would increase the pressure of the system which would favour the reaction that produces less moles.

Inert molecule never does anything, it does increase the pressure of the system so there are more collisions but it doesn't react so the collisions aren't successful.

c-l-a-u-d-i-a-a-a

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Re: VCE Chemistry Exam - 12/11/19 - Discussion/Questions/Solutions
« Reply #43 on: November 13, 2019, 08:50:52 am »
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Has anyone got solutions yet??

flozza00

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Re: VCE Chemistry Exam - 12/11/19 - Discussion/Questions/Solutions
« Reply #44 on: November 13, 2019, 09:01:02 am »
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I got : D A D.  D B.  B C B   B C A   D A A C(?) D B D. C D  D A B  A. A C  B B C B
Happy to debate