Chemistry 3/4 2013 Thread

[thushan]

Haha. That's a BS question. As if they pull that kind of trick.

[lolipopper]

this was their explanation. i think they forgot to account for carboxyl groups.

C18H36O2 and C18H34O2 are both unsaturated fatty acids, meaning that they each contain a
C=C double bond. Saturated fatty acids can be considered to have the molecular formula
CnH2n + 2O2. The fatty acid with formula C18H36O2 has two fewer H atoms than a saturated
fatty acid, giving it one C=C double bond and making it monounsaturated, whereas the
fatty acid with formula C18H34O2 has four fewer H atoms, giving it two C=C double
bonds and making it polyunsaturated.

[lzxnl]

Can we tell them to go screw themselves?

@thushan
There was an Insight question in which we had a solution of XY, we electrolysed it and at the anode, the bromothymol blue indicator went from green to yellow, thereby suggesting that 1. water was being electrolysed and 2. the solution was initially neutral.

Guess what their answer was? Potassium fluoride -.-
1 M KF has a pH of over 8, which is outside bromothymol blue's neutral range.

Get your act together, Insight.

[thushan]

Fail.

That said, my book's had a few fails too so I can't talk. I guess it's just an oversight.

[clıppy]

Fail.

That said, my book's had a few fails too so I can't talk. I guess it's just an overinsight.

I'll show myself out.

[xenial]

Hey I'm pretty nervous about chem. I think I did really really badly in English... I need a good score to offset that if I wanna get into biomed.

Can someone predict what I would've gotten in 2009?
Exam 1: 67-70/73 (depending on how strict they are with worded answers)
Exam 2: 74/76

What's that? Like a 45 maybe?

Sorry for spamming this thread. Those guys over at VTSD are clueless.

[neonperson]

2011 VCAA chemistry Exam 1 - Short Answer Question 5b) ii, and iii

I've looked at the assessor's report and they have everything to 4 sig figs...

but is it not 3 sig figs because of the "0.0525M" iron solution?

[Edward21]

2011 VCAA chemistry Exam 1 - Short Answer Question 5b) ii, and iii

I've looked at the assessor's report and they have everything to 4 sig figs...

but is it not 3 sig figs because of the "0.0525M" iron solution?

YES YES OMG. I was about to ask the same thing. I'm really quite conscious over sig figs, and I did it to 3 having looked at all the data I would use, but they're like ummm.. it's 4 which left me so confused. Is there some weird exception I'm not aware of?

[lzxnl]

I did that exam two days ago; same reaction. Screw them and their inability to read.

[lolipopper]

Hey I'm pretty nervous about chem. I think I did really really badly in English... I need a good score to offset that if I wanna get into biomed.

Can someone predict what I would've gotten in 2009?
Exam 1: 67-70/73 (depending on how strict they are with worded answers)
Exam 2: 74/76

What's that? Like a 45 maybe?

Sorry for spamming this thread. Those guys over at VTSD are clueless.

the average for an A+ was 78% for unit 3 and 84% for unit 4. so yeah probs 44-45. But im not an expert on this stuff.

[lzxnl]

Actually, I would have thought high 40s...78% A+ for exam 1? 68/73 is 93%. 74/76 is 97%

[lolipopper]

Actually, I would have thought high 40s...78% A+ for exam 1? 68/73 is 93%. 74/76 is 97%

i got those stats from TSFX. im not saying Xenial got those marks, im saying thats what was required that year for those grades.

[lzxnl]

How did TSFX get those marks? 44-45 doesn't mean high A+'s...provided of course xenial does well in SACs

[lolipopper]

How did TSFX get those marks? 44-45 doesn't mean high A+'s...provided of course xenial does well in SACs

i said the 44-45 from my self. but the A+ grade requirement from tsfx. but Xenial dont listen to me, only listen to Nliu.

[xenial]

Oh wow! Okay. I'm sac rank 1 at my school so that's not a problem I don't think. I know for most subjects (big generalisation) losing one or two marks is a 50, then losing one from there roughly equates to one study score. But Thushan said 2009 was a hard midyear so I wanted to check. I'll be ecstatic if that's high 40s though.