Apparently my last Chemistry teacher said oxidation states were out of the syllabus not too long ago so we didn't learn it.tehsky said:
Trial exams are marked by school teachers, that I know of.squance said:
I dunno why, but I kept thinking that glucose fermented to produce ethanol + water and was sitting there going: "WTF, can't balance" >.<; Luckily, I decided near the end of the exam to go: "Screw it, let's try carbon dioxide instead as a wild guess." Behold, a balanced fermentation equation. I was like: "..." when I saw that ^.^;tehsky said:
That's EXACTLY what I did haha. Those 3 main parts and talking about the 10:1 (N2opinion8d said:I think the BOD question was something along the lines of describing the test for BOD and evaluate its effectiveness for control and monitoring eutrophication...
I'm not sure how many marks i'll get but i basically defined BOD and then described the test:
Using a DO sensor on day zero and then again after placing the sample of water in a brown capped bottle in the dark at 20C for 5 days. The BOD is the difference in the two DO values.
I then talked about how when algal blooms, present because of eutrophication, die, the decomposers use up oxygen in the water to in order to break them down... Thus water that has been plagued by algal blooms has a very high BOD. Therefore BOD can be used as an indicator for algal blooms and eutrophication as the higher the BOD the greater the extent of eutrophication.
I finished off by saying although its useful as a test for monitoring eutrophication it should not be used alone as high BOD's can be due to other factors such as sewage contamination. Therefore further tests to determine nitrogen and phosphate concentration of the water should be carried out.
Briefly, thats how I interpreted the question anyway, any one else get anything similar?
and Halaby's congrats on ur first post
) ratio in addition with BOD tests. 
it was a hard exam, but i guess im just happy with the fact that i got to write down all i knew. but then again that doesnt necessarily guarantee me a band 5/6 mark. this exam was less stressful for me since my teacher left out the option topic, my class havent even started it yet, so you're waay ahead of us. also, i did ALOT of cramming the nights before, and surprisingly, to my luck, the quesitons such as BOD/eutrophication and the other 'not so common' type questions were the ones that i studied in depth for the nights before. and for the oxidation state question, i guessed the answer, and probably got it wrong, since i forgot how to calculate the oxidation states. dont worry about what others do and how they perform, it makes chemistry seem lifeless.schmetterling said:omg wow.
im like so overly jealouss of u ppl!
u think it was easy? dammn u must be an uLTRa smarty!
okay i liek didnt even get to answer that concerntration % question.. in fact i cant evn rememba wat it was.
that was so hard.
and i did the forensic Chem option. i totally went mind balnk .
im so sad cos i found it hard. and now its gonna birng my average down
good luck!
i iwhs i was like you ppl!
People have said that the HSC is almost always harder than the trials. Besides, the trials are named the 'trials' for a reason so there's no need to despair coz you'll do better in the hsc.
I posted what I reckoned was the right way to solve Q15 a couple of pages ago.schmetterling said:omg wow.
im like so overly jealouss of u ppl!
u think it was easy? dammn u must be an uLTRa smarty!
okay i liek didnt even get to answer that concerntration % question.. in fact i cant evn rememba wat it was.
that was so hard.
and i did the forensic Chem option. i totally went mind balnk .
im so sad cos i found it hard. and now its gonna birng my average down
good luck!
i iwhs i was like you ppl!
^Hope you got the right answer >.<;
*Wants to cry really badly at not getting a CFC question for god knows how many times now T.T
:wave: Nope. No-one has the exam. The security period is still up.chousta said:
Teachers handed out solutions coz they finished marking already. Did anyone get their marks back??
