Predictions for Chemistry 2014 HSC? (3 Viewers)

[SuchSmallHands]

There's a dotpoint about analysing information indicating changes in atmospheric ozone concentrations and describing the changes. Obviously there is a clear decrease in ozone concentration during the use of CFC's and stuff, but what is the general consensus today? (This relates to evaluate the effectiveness of steps taken to alleviate problems...)

I've heard people say that yes, high effectiveness and ozone layer is regenerating
BUT ALSO i've seen (and this is my stance also) that there is minimal regeneration of ozone layer due to the longevity of ozone depleting substances (recall regeneration of Cl. in CFC's)

Depletion hasn't increased in a decade and some parts are thickening (though the regeneration isn't uniform). That's according to the UN environment report released earlier this year (ie. main source of all of my statistics for this section)

 

[QZP]

Depletion hasn't increased in a decade and some parts are thickening (though the regeneration isn't uniform). That's according to the UN environment report released earlier this year (ie. main source of all of my statistics for this section)

Do we have to know specific sources of information ??

 

[SuchSmallHands]

Do we have to know specific sources of information ??

I don't really think so, no. I just wanted to justify to you that I wasn't pulling this out of my ass haha

 

[SuchSmallHands]

How much do we have to know about the ozone hole at Antarctica during Spring e.g. its cause? I don't see any reference to it in the syllabus but all textbooks go into it...

I have nothing about that in my notes, and I've managed to address every dot point, so I don't think it's necessary. If you already know about it, it can't hurt though.

Edit: ozone depletion was a six marker last year. Probably won't be required to know it to too much depth this year.

 

[faisalabdul16]

I was under the impression that halons were halogenated, not necessarily brominated. Many don't contain bromine (eg Halon 10001)

YES! Sorry i confused myself with something, my notes say what you said.

Thank you for clearing that up!

New questions?

 

[SuchSmallHands]

Literally the worst six mark HSC chem question they've ever given?

Assess the need for chemists to collaborate when monitoring the environmental impact of a named electrochemical cell.

Have fun

 

[enigma_1]

Literally the worst six mark HSC chem question they've ever given?

Assess the need for chemists to collaborate when monitoring the environmental impact of a named electrochemical cell.

Have fun

Serious? This was my favourite and easiest one?

 

[SuchSmallHands]

Serious? This was my favourite and easiest one?

I haaatteee it, it's barely even about chemistry! It's the highest marked question in the core of a chem exam, I want to talk about chemistry not the fucking virtues of team work.

 

[faisalabdul16]

Literally the worst six mark HSC chem question they've ever given?

Assess the need for chemists to collaborate when monitoring the environmental impact of a named electrochemical cell.

Have fun

hahaha this is the worst question!

Chemists need to collaborate when monitoring the environmental impact of the lead-acid cell battery to ensure the environment is safe from detrimental chemicals which could potentially kill organisms, both plants and animals. Different branches of chemistry such as the environmental chemist, and the analytical chemist are required to collaborate and share information from their area of expertise to not only create a sustainable cell that can meet the needs of humans but also the environment.
Lead Acid Cell
Anode - Pb(s) + SO4(2-) -----> PbSO4(aq) + 2e(-)
Cathode - PbO(s) + 4H(+) + SO4(2-) + 2e(-) -----> PbSO4(aq) + 2H2O(l)
Electrolyte - Sulfuric Acid.
Uses - primarily as a battery cell in cars (6 cells connected)
Advantages - rechargeable and can store solar energy when connected to solar panels.

The lead acid cell is as apparent, one of the most beneficial cells created as it is widely used as a battery in motor vehicles. It's wide is use is because of it's ability to be recharge, thus reducing costs as it is able to work efficiently for years. However, with these advantages, come serious environmental threats which need the collaboration of both an analytical chemist and an environmental chemist to work out solutions to dispose of these batteries and how to combat problems such as the contents being leaked out into the environment. The environmental chemist needs to collaborate with the analytical chemist to inform him/her of the dangers of lead contamination in the environment. Lead (from the cell) is a heavy metal pollutant and if disposed of incorrectly can be very detrimental to the environment. Lead is toxic and causes serious neurological disorders amongst humans, causing mental retardation in children and brain damage in general. Lead must NOT be disposed of in the environment as it enters the food chain and bioaccumulates, causing death amongst the organisms which consume animals with a lead concentration in their body. The role of the environmental chemist is to inform the analytical chemist about particular areas of contamination, such as water, soil and certain foods. THEN, it is the role of the analytical chemist to numerically measure the concentration of the lead using Atomic Absorption Spectroscopy, a meticulous device which measures concentrations of metals up to parts per billion. The role of the analytical chemist is to gather concentration levels and report back to the environmental chemist, who makes a judgment and acts accordingly to the results. The environmental chemist (if levels are unacceptable) would need the assistance of other chemists to devise a plant that will quickly and easily remove the lead or get rid of it in the contamination site. Furthermore, this cell uses sulfuric acid as an electrolyte, which poses a threat as it brings about detrimental environmental impacts. IF sulfuric acid enters waterways, it could potentially kill aquatic life and prevent fish from extracting magnesium from the water to maintain their skeletal structure. Sulfuric acid if disposed of near areas of plant growth, it could potentially kill or inhibit plant growth as the acidity of the soil changes, preventing plant growth as they proliferate within a small pH range. The sulfuric acid also depletes soil from nutrients, again disallowing plants to proliferate.

Collaboration is required for dealing with the potential environmental impacts that the lead acid cell has. Without collaboration, maintenance of the environment and human health would be extremely slow, and without chemists who measure numerically the severity of the pollution, others would not know and result in horrific ramifications. Collaboration allows for chemists with different areas of expertise to present their knowledge to combat problems in a quick manner; in order to keep the environment safe from detrimental toxins. Collaboration is indeed a must.

I would write more, but ceebs. hahaha

 

[QZP]

yall need to start sticking to concise responses... that number of lines is about a 20 mark question

 

[enigma_1]

I haaatteee it, it's barely even about chemistry! It's the highest marked question in the core of a chem exam, I want to talk about chemistry not the fucking virtues of team work.

Ahahah yeah i see what you mean. But when I writing an answer to this I really only saw 2-3 marks for talking about the collaboration between the scientists. The rest was about:

-lead acid cell battery and give equations of anode, cathode, electrolyte

-How the lead is released into the environment from the casing, although it is a renewable battery, some of it still is

-it leads to bioaccumulation and biomagnification killing animals andfish

-lead fumes are toxic and it causes intellectual retardation and causes hyperactivity in young kids and aggression

-when lead is injested, it takes a long time to come out and it's also poisonous to humans

-the negative effects of lead including it is a toxic heavy metal

-AAS is used to monitor it's concentration in the environment because aas is a senstivtive analytical technique measuring lead concentrations to ppm or ppb

Now you say BECAUSE of these problems the scientists need to collaborate to monitor the concentration of the lead released from the pead acid cell battery

faisal can go through the boring collaboration lel

 

[enigma_1]

Ok he already did lawl

 

[faisalabdul16]

yall need to start sticking to concise responses... that number of lines is about a 20 mark question

Your answer has to be detailed.

For 6 marks, you have to not only talk about the composition of the cell, you have to talk about collaboration, you have to talk about the chemicals which pose a threat, then you have to talk about which chemist does what, and as your talking about the chemists you have to describe their work and then again you have to give an evaluation.

It's going to be long, in order to secure your 6 marks.

 

[enigma_1]

yall need to start sticking to concise responses... that number of lines is about a 20 mark question

Yes omg good idea. Ok I have a challenge, when you're answering questions, you can't go overboard and you have to wrote concisely, otherwise it's benefitting no one. So yeah from now on please be concose everyone

 

[enigma_1]

Your answer has to be detailed.

For 6 marks, you have to not only talk about the composition of the cell, you have to talk about collaboration, you have to talk about the chemicals which pose a threat, then you have to talk about which chemist does what, and as your talking about the chemists you have to describe their work and then again you have to give an evaluation.

It's going to be long, in order to secure your 6 marks.

Would you actually write that much though? And how long would it take you to do so? Please don't say 2 minutes :/

 

[faisalabdul16]

Yes omg good idea. Ok I have a challenge, when you're answering questions, you can't go overboard and you have to wrote concisely, otherwise it's benefitting no one. So yeah from now on please be concose everyone

Alright, lets make some sort of system which addresses marks and lines.
For 7 marks how many lines y'all reckon?

 

[faisalabdul16]

Would you actually write that much though? And how long would it take you to do so? Please don't say 2 minutes :/

Na there are some areas which i believe i have repeated myself

 

[enigma_1]

Alright, lets make some sort of system which addresses marks and lines.
For 7 marks how many lines y'all reckon?

Yeah ok, I'm on my phone so I dunno.
But maybe do it on ms word so you can see how many words and then like for a 7 marker I would think 250 -300 words approx and spend 10 minutes on it since you're typing and it's faster than writing.

 

[MrBeefJerky]

Literally the worst six mark HSC chem question they've ever given?

Assess the need for chemists to collaborate when monitoring the environmental impact of a named electrochemical cell.

Have fun

LOL this would be so difficult if you only studied dry cell

 

[faisalabdul16]