Predictions for Chemistry 2014 HSC? (2 Viewers)

[zhertec]

But what if you don't know anything about the option?



Yea, the easy 1-5 marks on equilibrium lol

Theres that, but think about the other parts of industrial, 5 marks on equilibrium 20 marks on regurgitation. Done.

 

[faisalabdul16]

Could a 70 align to band 5? Not gonna bother with the option

Yes but what makes you think you're going to blitz through the core?

It's chemistry, anal marking criteria. DO NOT give up now. Study for the option, who cares if you hate it. There's only one more day of studying for chem and then you won't have to in a long time. Just push yourself, you don't want to regret it.

 

[faisalabdul16]

Hopefully for industrial it's the 3 cells.

Mercury Cell - Sodium dissolves in mercury forming an amalgam. The amalgam flows out of the cell where it does not react with water or chlorine. Continues flowing until it reaches the decomposer where it is reacted with water. Here the amalgam decomposes (sodium is released) to form mercury, hydrogen and sodium hydroxide. Mercury-contaminated sludge is separated from the amalgam and the mercury recycled in the cell. The remainder is reacted with sodium sulfide. Some of the mercury which was leftover forms mercury (I) sulfide which is disposed of by adding it to cement, setting it in bricks and using these as landfill. Sodium hydroxide produced is pure as it was reacted with water which contained no chloride. 50% sodium hydroxide solution formed as well as the dry form.

Diaphragm Cell - Two electrolyte solutions are separated by a diaphragm made out of asbestos. Both compartments contain saturated brine. As electrolysis proceeds, chlorine ions are reduced at the anode and water is reduced at the cathode, forming hydrogen which is used in the hydrogenation of vegetable oil. The cathode compartment increasing becomes alkaline and is periodically removed. Sodium ions migrate from the anode compartment through the diaphragm and to the cathode compartment to neutralise the charge of the hydroxide ions formed. The diaphragm also allows for some diffusion of hydroxide and chloride ions. The solution formed at the anode compartment is a mixture of sodium hydroxide and sodium chloride which is further purified through crystallization of sodium chloride. About 50% sodium hydroxide formed as well as 2% sodium chloride.

Membrane Cell - Two electrolyte solutions are separated by a cation exchange teflon membrane which only allows the movement of sodium ions across and prevents hydroxide ions from moving through. Newly developed membranes allow the electrodes to be very close to each other on opposite ends of the membrane. This increases the efficiency of the cell and thus reduces costs. In comparison to the other cells, it produces sodium hydroxide in a cheap and efficient manner (less energy consumption) and is environmentally friendly.

Have not even talked about environmental issues, advantages and disadvantages or improvements (partitions particularly)

Would be easy 6-7 marks.

 

[mreditor16]

Yes but what makes you think you're going to blitz through the core?

It's chemistry, anal marking criteria. DO NOT give up now. Study for the option, who cares if you hate. There's only one more day of studying for chem and then you won't have to in a long time. Just push yourself, you don't want to regret it.

this

+1

 

[zhertec]

anyone else finding it hard to match your written asnwers with the ones of success one answers? Cause I am and it's really annoying >.<

 

[faisalabdul16]

anyone else finding it hard to match your written asnwers with the ones of success one answers? Cause I am and it's really annoying >.<

Hahaha success answers are not that good.

 

[GOsie]

Explain the role of the conjugate acid/base pair, H2PO4 - / HPO4 -2, in maintaining the pH of living cells. Include chemical equations in your answer. (3 marks)

2011 HSC question.

Any takers?

 

[QZP]

Explain the role of the conjugate acid/base pair, H2PO4 - / HPO4 -2, in maintaining the pH of living cells. Include chemical equations in your answer. (3 marks)

2011 HSC question.

Any takers?

- Living cells need an optimal pH (~7.4) for proper biochemical functions. Thus, the conjugate pair forms a buffer to resist changes in pH to main when small amounts of acid/base are added to maintain aforementioned optimal pH
- [Insert equation for addition of H+]
- [Insert equation for addition of OH-]

 

[faisalabdul16]

Explain the role of the conjugate acid/base pair, H2PO4 - / HPO4 -2, in maintaining the pH of living cells. Include chemical equations in your answer. (3 marks)

2011 HSC question.

Any takers?

The role of the aforementioned buffer is to withstand pH changes in living cells to maintain homeostasis, a constant internal environment which allows for enzymes to operate optimally, and since the activity of enzymes influence metabolic activity, a constant pH environment equates to optimal enzyme activity and metabolic efficiency. This buffer helps to prevent cell death and on a large scale organ failure.

Insert equations.

 

[emilios]

The role of the aforementioned buffer is to withstand pH changes in living cells to maintain homeostasis, a constant internal environment which allows for enzymes to operate optimally, and since the activity of enzymes influence metabolic activity, a constant pH environment equates to optimal enzyme activity and metabolic efficiency. This buffer helps to prevent cell death and on a large scale organ failure.

Insert equations.

Chemistry, not bio m8

 

[faisalabdul16]

Chemistry, not bio m8

HAHAHAHA Was waiting for someone to say that.

You can incorporate knowledge from all sciences.

 

[zhertec]

Guys any suggestion on how to write better in chem? lol cause many times, esp in trials, I tend to ramble ish, but then the sample answers etc are often more succinct then mine, which makes me think that I'm writing too much...so is it better to write more than less? lol

 

[QZP]

Guys any suggestion on how to write better in chem? lol cause many times, esp in trials, I tend to ramble ish, but then the sample answers etc are often more succinct then mine, which makes me think that I'm writing too much...so is it better to write more than less? lol

Focus on answering the question rather than using unnecessary depth of knowledge (BOSTES sample answers reflect this notion). Pay attention to every detail in the wording of the question; if you see some word that seems out of place - chances are that's where the marks are. In HSC chem, understanding the content is simple so don't fool yourself into thinking that you know what to write. My teacher always puts RYBQ when marking my responses lol (read your bloody question)

 

[zhertec]

Focus on answering the question rather than using unnecessary depth of knowledge (BOSTES sample answers reflect this notion). Pay attention to every detail in the wording of the question; if you see some word that seems out of place - chances are that's where the marks are. In HSC chem, understanding the content is simple so don't fool yourself into thinking that you know what to write. My teacher always puts RYBQ when marking my responses lol (read your bloody question)

Haha nice teacher xD But I do read the question! (well I think I do), its always small marks lost on multiple pages that pisses me off, and for me, the hardest part is trying to write to what I think the marking criteria is lol

 

[SuchSmallHands]

Do you guys use dots or crosses on a line graph?

 

[emilios]

If you can blitz through the calculations then by all means do so... but take your time with carefully wording your written responses. Some people in my cohort are all like "yeah that was 2ez finished in half the time" but they end up losing marks for poorly worded answers, whereas ive done well by pretty much using the entire exam time (save maybe 5 mins). Unless you're way behind (finishing core at the 2hr 30 mark) then of course hurry the eff up LOL

 

[QZP]

Do you guys use dots or crosses on a line graph?

Crosses o: But my teacher said to do dots and circle them. But this is too weird for me so I use crosses

 

[zhertec]

Do you guys use dots or crosses on a line graph?

I use really dark dots so they can clearly see that I've plotted a point.

and @emilios (since I don't know how to bloody multiquote lel) I use all the time and after the exam I generally feel good about it, but the returning results arent that great it's like I think I've written the write thing, but I haven't (according to the markers). These small mistakes tend to build up immensely, causing me to lose a fairly high amount of marks overall.

 

[SuchSmallHands]

Crosses o: But my teacher said to do dots and circle them. But this is too weird for me so I use crosses

Yeah wtf that's so weird haha.

 

[SuchSmallHands]

and @emilios (since I don't know how to bloody multiquote lel) I use all the time and after the exam I generally feel good about it, but the returning results arent that great it's like I think I've written the write thing, but I haven't (according to the markers). These small mistakes tend to build up immensely, causing me to lose a fairly high amount of marks overall.

I feel the exact same