Cssa Trials... (2 Viewers)

[velox]

thankgod for that combustion question !!! i got around 300

well -300 but the negative indicates exothermic


Like i said, i put 0.2 oysters

12mg per day

one oyster contains 200ppm

12/200 = 0.06 so to reach the minimum, just the 0.2 would be sufficient = I don't know tho

i wasn't taught ppm really, tho i was under the assumption that its ppm = 1mg/l

Hmm ill ask my tutor or some friends tomorrow. This question is annoying!

 

[currysauce]

the oyster one, yes please do LOL

 

[~ ReNcH ~]

opps, yeah i mean -300

It should be +300 since its the molar heat of combustion, which already implies that it's exothermic. Were it asking for the molar enthalpy, then -300 would be used since enthalpy refers to the amount of heat absorbed.

 

[~ ReNcH ~]

Hmm ill ask my tutor or some friends tomorrow. This question is annoying!

Yep...go for it (particularly the tutor idea)
It would give me some peace of mind

 

[currysauce]

i don't think i'll be penalised, if so, maybe 1/2 a mark - oh well

 

[~ ReNcH ~]

i don't think i'll be penalised, if so, maybe 1/2 a mark - oh well

No half marks in the HSC...though I suspect that they would be lenient in regards to + and - since it's really the calculation that's important. +/- 3xx would get you full marks imo, unless the criteria stated otherwise.

 

[currysauce]

lets hope

girl coming second said she got around 700 so ! woo

at least thats a couple marks i can lose in the mc

 

[ishq]

AH!!!
That was SO weird!
Our school changed most of the questions....but ...

people - please tell me

molar hear of comb ~ 300
The neutralisation one ~ 700

Also - whoever did shipwrecks : did you write a massive essay for the last question? Because I just kept on going...and going...

Ah! Such a weird paper...
I already said that...

 

[velox]

Ishq did u do the :An adult needs 12mg of zinc per day. An average oyster contains 200ppm of zinc. How many oysters are required to fulfil the daily intake of zinc for an adult?

 

[HotShot]

Hang on, when did you guy do the chem test? I did mine today! Did u do it today?

 

[~ ReNcH ~]

lets hope

girl coming second said she got around 700 so ! woo

at least thats a couple marks i can lose in the mc

Hmm...well.
Mass of water was 100g, C=4.18, Change in temp was 34

.'. ^H = 100 x 4.18 x 34 = 14212 J/2.1 g of ethanol
M(ethanol) = 46.068 g/mol
.'. No of moles of ethanol = 2.1/46.068
.'. Molar heat = 14212/(2.1/46.068) = ~312 kJ/mol.

 

[ishq]

Nope: We had a shitty question put over it
Q: What is the difference between destructive testing and non-destructive testing in chemistry? Describe with one example of each.

10 bucks to whoever gets that.

 

[HotShot]

Ishq did u do the :An adult needs 12mg of zinc per day. An average oyster contains 200ppm of zinc. How many oysters are required to fulfil the daily intake of zinc for an adult?

I think the questions wrong i kept getting 60, but the answer is pretty sure 6. i think its suppoed to 120mg!

 

[~ ReNcH ~]

Nope: We had a shitty question put over it
Q: What is the difference between destructive testing and non-destructive testing in chemistry? Describe with one example of each.

10 bucks to whoever gets that.

That was from a pervious CSSA paper...either 2002 or 2003.

 

[physician]

Hang on, when did you guy do the chem test? I did mine today! Did u do it today?

yeh CSSA are scheduled for today

 

[ishq]

Yeah, I know - thats why I knew it.
Most people didnt..

Its such a random question - where is it in the book/syllabus????


molar hear of comb ~ 300
The neutralisation one ~ 700
Right?

 

[Haku]

of course, i was amazed how fast this thread had developed. lol

by anywayz how can u get 3XX for the molar heat of comb, i got 139X.XXX and that seem close to the results from the books, so i was hoping it was right as i got 29.99kj/g so times that by the molar mass for ethanol.,

well correct me if i am wrong, hope i am now,

so how did u do the question 15 of MC, i cant get any of the ansers, plz enlighten me

 

[richz]

destructive indicator cant use substance anymore
non destructive pH meter doesnt destroy substance and can be used after

 

[physician]

I'm over chem...

had enough.. i think i'll start studying for maths... later guys

 

[~ ReNcH ~]

I think the questions wrong i kept getting 60, but the answer is pretty sure 6. i think its suppoed to 120mg!

I think it's meant to be 1.2mg i.e. 1.2/0.2 = 6