General Thoughts: Chemistry (3 Viewers)

[brent012]

lol. i said it precipitates any fertiliser that might effect the pH of the soil. would get a mark for it ?

Wasn't it just worth one mark? What they are looking for is that you talk about the colour and how barium sulfate won't affect the pH, I had a mindblank about the colour lol so just wrote about how it doesn't affect pH and im not expecting the mark for that.

 

[muzeikchun852]

Don't worry about it, it was only one mark.

yeah i know. not too stress about it

 

[CalumGemmell]

no.

What if i said it helps to take particular chemicals out of the solution thus making a pH indicator test easier to interpret?

 

[dan2452]

What the fuck was liquid X???

I said it was sulfuric acid and said shit about how it dehydrates the crystals.

I said the same thing. But, it was BS on my part, so not sure if we're right -_-

 

[latashyoussef]

I'm pretty sure my ATAR would be horrible if I hadn't chosen 13 units.
After that exam, I no longer regret not dropping German in year 11.

Haha that sentence is, grammatically, all out of whack haha.

 

[silence--]

for neutralisation i said energy required in bond breaking is less tahn energy needed in bond formation thus always exo. (i think this was what we learned in prelim for why things are exo/endo)

meh idk.

 

[khorne]

What if i said it helps to take particular chemicals out of the solution thus making a pH indicator test easier to interpret?

It doesn't react, it's just used so the colour of the indicator can be seen and it doesn't interefere by being a neutral salt

 

[b3kh1t]

curios as hell lol what do you reckon the state rank mark will be??

 

[kleenextissues1]

I wrote something about that it was still necessary to note the theory in the case of pH = -log[H+] ... amongst other things

What do you guys think of this?

 

[RAWR24]

Industrial chemistry WTF!!!!!! Seriously should just pull down your pants and get ready to be raped FML!!! anywho tg i have 12 units :L

 

[lolcakes52]

What do you guys think of this?

Nope, you can calculate pH using both systems. But it requires harder concentrations for bases that dont have OH and acids without H so for that purpose its really irrelevant.

 

[CalumGemmell]

What do you guys think of this?

No idea, but I'm guessing from what everyone else had said I'm wrong. I talked about Arrhenius' definition being about hydrogen ions, while the bronsty theory involved proton transfers, and seeing as proton IS a hydrogen ion it's still valid.

 

[kleenextissues1]

Nope, you can calculate pH using both systems. But it requires harder concentrations for bases that dont have OH and acids without H so for that purpose its really irrelevant.

Damn lol

 

[jamesfirst]

Dang I think I lost 6 marks alone in the M/C...


Got titration wrong (HOPE I get 1 mark) and pretty sure I got most of the calculation wrong.


I'm scared that I might not get a band 6

 

[utanobeiiby]

cause he reaction in aqueous solution is always HO3+ + OH- -> H2O which always produce 57kj/mol all other ions will be spectators if reagents are strong acids and bases..

 

[brent012]

I'm scared that I might not get a band 6

Lol seriously dw about it in a few months time you wont even care, it sounds like you think you will be on borderline band 5/6 so it probably wont affect your atar unless you are relying on HSC Plus/Bonus marks for band 6 in chem.

 

[utanobeiiby]

>< can't imagine i didn't finish it >< i though the test was doable but i left our like 5 marks on the stupid modeling shit >< but i;m pretty confident on what i have done so hoping for a raw mark ~92

 

[shakky]

The -56kJ per mol thingo is based on the fact that for all neutralization reactions the net ionic equation is the same, if both the acid and based are strong. As for the exam in general, I thought it was a cake walk. The only really hard question was the one where you had to figure out the concentration of citric acid, not because it took a lot of knowledge but because it was complex. I got 0.1586 or something as the final answer and I am so sure its right. I can't remember learning why barium sulfate should go in soil when testing pH so i just bullshitted my way through.

Yes the numbers 0.1586 sounds very familiar, and I think I got that too. And BaSO4 is used to absorb the indicator and by being a white colour the indicator colour can be clearly seen.

 

[khorne]

Yes the numbers 0.1586 sounds very familiar, and I think I got that too. And BaSO4 is used to absorb the indicator and by being a white colour the indicator colour can be clearly seen.

I don't remember exactly, but it does sound fairly right

 

[Tasha270494]

Arrhenius' theory is useful because it explains acidic/basic behaviour really well in aqueous media. The theory says that acids in aqueous media produce H+ whereas bases produce OH- ions.
It clearly explains neutralisation reactions, where equal amounts of H+ and OH- when combined produce water. in this respect, it can also help in volumetric analysis such as titrations when equal moles of H+ and OH- when combined reach the equivalence point.
It also helps to clearly represent the strength of acids in solution - e.g. A 1M of HCl produces 1M [H+] whereas 1M CH3COOH produces less than 1M [H+].
.. also helps with concentration of acids/bases