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Chem: 96 Cl. Grk: 97 Maths (05): 96 Maths Ext.: 48/50 English: 92 Chinese: 90 Chinese Ext: 47/50 (2nd in state) UAI: 99.80

hey guyz.... SAM: 99.75 Actualy UAI is 99.80 so stoked!! aahahahaa! yyeewww!!

hey guyz.. i got 99.80 totally stoookkkeeed! haha still can't believe it... what i plan 2 do next year ay?....hhmmm.. most likely get on the dole and b a dole bludger! haha nahhhh mayb rocket engineering

sorry mate, in the question they only had to one sig. fig, the conc. was 0.02 and 0.01 if i remember correctly :S, i believe that is only 1 sig fig? and since conc. is to one sig fig, you must give pH to one dec. place. thats the rules of conversion of conc. to pH.

pH= .85 is not correct, the pH is .9 (u had to round it up!) this is because of the significant figure/decimal point rules associated with working out pH and [H3O] conc. the rule is; however many sig. figs they give concentration, is the amount of decimal places the pH must be. they gave conc...

Hmm... i got 385mg/L Maybe you guys rounded up too early or sumthing.... i kept it exact the whole way till the end..

i think that saying they averaged wrong, i.e; included the rough volume, is not sufficient, its too much of an assumption thats not well justified, otherwise the markers will have to accept all titration errors for the qt answer, i.e, didn't rinse properly, etc... so i think the answer is the...

find no moles of HCl reacted with NaOH, then work out the excess. then use the PH formula. u get smthing like 0.854... but you have to round it up to 0.9 (1dp)

first find moles of EDTA used, then convert to grams, convert to mg, then work it out as mg/L. i got something like 835mg/L if i remember correctly...

the standad solution of EDTA may have been dissolved in water that was not de-ionised. So there may have been calcium ions already present as in hard water, hence the greater concentration of Ca ions using the volumetric method.

Pretty ave test. Stoked about the 7 marker in the option of industrial chem- natural source one. That will really sort out the top students from the average ones. The questions weren't random, they were just a different style from last few years, i.e, more prac based and required more...

The fact of the matter is... who cares what the cut off is. You should be doing everything you can to try and get the highest mark possible within your own capability. No one should be aiming for '70' or '65+', you have to aim for 84.... 'aim for the sky so you still fall above the tree tops'

the key is doing past papers. By doing them you get exposure to the different sorts of questions... to study for Q6 & Q7s, the way i study is just do q6 and 7s of about 20 past papers. At the start you might be demorilised, but as you continue to do them you'll become accustomed to the style of...

Got 76/84 (1). Pretty happy but toooo many silly errors! AAH!!

Usually after the exam the examiners/teachers collect the papers so it will be very hard to get your hands on it. it was approx. the same difficulty as last years paper. so if you're okay with that, you should be fine.

The paper was very solid, but not as hard as some of you are making it out to be. I think this years paper was very 'on parr' with the actual HSC papers. i mean seriously, it's ext. maths, its not meant to be 'easy'.

Ey GJI how'd you go in Chem trial?

Yeh, I've seen the "Neap papers. they're quite difficult, compared to the CSSA

My mistake, since Sulfuric acid is diprotic (2 hydrogens) you MUST multiply the concentration by 2 so : pH = -log [2 x 5 x 10-4] =3

It is assumed that the acid is completetly ionised. This tells us that the hydrogen ion concentration is equal to the concentration of tha cid (100% ionisation). So the pH is pH= -log [H+] = -log [5 x 10-4 mol L-1] = 3.301029996 = 3.3 Hence, the solution is B