Section I: Short Answers (2 Viewers)

[adnan91]

yeah you would expect so
might lose a mark off your graph though if it isn't accurate??

No the graph was correct. but i read 1.7 not 1.6 thats not a mistake. i knew how to calculate the mass of zinc in it. I doubt theyll take a mark off. They would take a mark of if i read like 1.1

 

[Muchi]

na its just that dans person says that the platinium is the cathode so isnt it reduced?

 

[fishbulb]

No the graph was correct. but i read 1.7 not 1.6 thats not a mistake. i knew how to calculate the mass of zinc in it. I doubt theyll take a mark off. They would take a mark of if i read like 1.1

I got 1.7mg/L too, im pretty sure it is right. I drew the graph perfectly.

 

[adnan91]

I got 1.7mg/L too, im pretty sure it is right. I drew the graph perfectly.

sweeeet

 

[tacogym27101990]

im sure there'd be a +-0.1 leeway anyway

 

[glockenspiel]

The galvanic cell question had Nickel as the anode, Platinum as the cathode. Nickel oxidised, chlorine gas reduced. I forget the voltage, but its easy to work out if you take those two. Also, the green one got greener (Ni2+ increased as Ni oxidised and NO3- moved from the salt bridge so there wasn't a build up of charge) and nothing happened to the other one.

And I don't know with the AAS question, chemistry markers are incredibly picky so there's a good chance they might decide to be harsh and punish you. Of course if the answer by the board is within a range you'll probably be ok.

I thought in general the questions weren't really too bad. It could have been a lot worse. I thought the galvanic cell probably wasn't worth enough marks for its level of difficulty and the catchment question was a bit cruel, but it was ok other than that.

 

[davidlee90]

How about the critical evaluation of the statement based on ethanol as a fuel? what did u guys write about?

 

[Muchi]

umm i think i liked the ethanol question. i wrote about electrical consumption used in processes used to manfacture ethanol and also the fact theres the use of a renewable source. i didnt mention the photosynthesis reaction to prove that co2 produced is used by plants but im not sure if im going to lose marks on that. also i didnt mention anything about it being a petrol extender etc, i didnt think it was relevant but who knows.

 

[Muchi]

ooo just realised, might have flunked that question. someone wrote about combustion & photosynthesis to reflect the cyclic nature. damn, i didnt think of that.

 

[Muchi]

hey did they mention that carbon dioxide is neutral and that plants use up the co2 in photosythesis? if they did that could be a saver for me coz the markers hate it when students repeat whats present in the paragraph and test what you know(my teachers a hsc marker)

 

[Muchi]

and to top off this some other kid mentioned that adding ethanol to petrol increases co2 released!!! Man i wish i had minds like these people

 

[iEdd]

I wrote three balanced equations. One to show that CO₂ and H₂O convert to glucose. Then a glucose to ethanol, releasing some CO₂, then finally the ethanol to H₂O and CO₂. I explained in between equations and then at the end wrote that as the original reactants are CO₂ and H₂O, as are the final products that ethanol is carbon neutal.

Edit: I forgot to mention that it is added to petrol. However, it does say ethanol, and when ethanol alone burns, it IS a carbon neutral fuel. Hmmm

 

[Zephyrio]

I said that essentially, ethanol isn't carbon neutral becuase you have to burn vast amounts of fossil fuels to even produce it in the first place.

 

[Zephyrio]

In regards to the half-cell with the chlorine, wouldn't it have a somewhat greenish tinge? I thought chlorine had that kind of colour, especially with the gas being a green colour. So if you're pumping a greeny gas into the half cell, wouldn't it assume this colour (since the electrolyte and Cl-(aq) would be colourless).

I also said that the other half-cell would take on a silvery colour because the nitrates would migrate to the other side, leaving your Ni2+ ions in solution? LOL.

Anyway, I've calculated that I've lost around 10 marks altogether. I hope I get that 92 (after alignment of course)!!!

 

[iEdd]

That's assuming you use fossil fuels to produce ethanol. I guess most production plants are though - should've mentioned that.

No. Chlorine is reduced. That means chlorine becomes chlorine ions. It's the opposite of making Cl gas.

 

[tommykins]

For the potential voltage did you guys use chlorine gas or aqeuous?

 

[danz90]

For the potential voltage did you guys use chlorine gas or aqeuous?

Gas, because the Chlorine gas is being reduced, not the Chloride ions in the solution.

 

[tommykins]

Gas, because the Chlorine gas is being reduced, not the Chloride ions in the solution.

*raises fist in the air*

hell ye

 

[danz90]

btw, what did everyone get for the [HCl] in the titration one?
I think I screwed that one up with stupid error

 

[tommykins]

i don't remember, i got a really nice roundable number though :0