chem ASS task (1 Viewer)

[fashionista]

Hey y'all,
I was jus wondering if for hsc chem anyone had to do an assessment task where u had to compose and perfrom an experiment????? im doin one on the citric acid content of diffrnt citric fruits but i dunno how to set it out and how much stuff i shud put in to my report!!!!!!!!!!!!
can any one help???
thanx heaps!!!!!!! :jaw: :wave: :burn:

 

[juggernaut]

i had to compose a given experiment in yr 10
somethin bout which nappy can hold the best liquid

anyway, include the usual; aim, apparatus, procedure, hypothesis, observations, results, conclusion
also maybe take photos of the experiment and include those

 

[iambored]

but if you are doing it in class then you will obviously not be able to take photos

yes i did a prac in class, i am sure everyone will have as you must for hsc chem

set it out like someone said above, for a report (if it is in class) i would just see ho wmuch time you have left (leave as much time as possible) and then write as much as you can in that time, (provided it is good stuff you are writing).

 

[jm1234567890]

i did one on galvanic cells

You could use this as a guide

i got 95, so you need a better risk analysis and a better discussion.

 

[sneaker]

hasn't that experiment been taken out of the acidic env syllabus? Isn't the only one there to determine the sulfate content in a fertiliser?

 

[jm1234567890]

Originally posted by sneaker
hasn't that experiment been taken out of the acidic env syllabus? Isn't the only one there to determine the sulfate content in a fertiliser?

The assessment task had no limits, you design any experiment remotely related to syllabus

 

[fashionista]

we got given a choice of 6
1. acid content of fruit juices
2.CaCO3 content of eggshells
3. alcohol content of drinks
4phosphorus in fetiliser
5.nitrogen in detergents (or maybe the last 2 wehre the other way round)
6. factors affecting algal growth
they took 4 and 5 out bcoz they were 'too hard'

 

[fashionista]

i piked 1 (duhh) and i modified it a bit.. like comparing the acid content of orsnge juice with cordial with fizzy with oranges. is that a good idea?? if not im open to suggestions
thanx heaps for all ur help!!!!!

 

[fashionista]

omg primordial member!! u went to smiths hill too??????

 

[jm1234567890]

Originally posted by fashionista
we got given a choice of 6
1. acid content of fruit juices
2.CaCO3 content of eggshells
3. alcohol content of drinks
4phosphorus in fetiliser
5.nitrogen in detergents (or maybe the last 2 wehre the other way round)
6. factors affecting algal growth
they took 4 and 5 out bcoz they were 'too hard'

you go to smith's hill?
lol, they must have thought the free choice prac assessment was too much.

the person who did the calcium carbonate in egg shells got 100

if your good at chem i recomend doing the

3. alcohol content of drinks

alot more to talk about in discussion, risk analysis, etc.
and all you have to do is a few distillations (mabye fractional distillation, but i don't think we have the equipment). However, you could always say that it would have been more accurate with a fractioning column.

 

[fashionista]

so if i sed in my discussion that my results may be inaccurate due to the presence of ascorbic or phosphoric acid in addition to the citric would i be marked down?or wud i be told that i shud have accounted for that before hand and therefore modified my exdperiment? if i react a fizzy drink with NaOH will both the citric acid and the other present acid react? and then if they do how will i do the calculations for two acids reacting with the NaOH if I am to find out the concentrations of both of them?? wud i jus be better off to switch my experiment to quantitating the acid content of different citric fruits? :wave:

 

[Ziff]

Yeah all of my friends have been asking what I did last year but I keep explaining to them they've decided to restrict what they can do.
One of my friends is doing the citric acid/orange juice one... to see if it can be done he used a turkey baster in imperial measurements and an indicator he made from plants in the backyard! Surprisingly, it worked though the accuracy and precision could be a bit wonky...

I got 91 for mine because it was mostly thrashed together. Do you have to include background information as well?
Then it's about a page of b/g info, aim, hypothesis, method, variables, control, risk assessment, discussion, conclusion. Risk assessment is easy as you can crap on about the risky side of playing with acids, why you should use low molar acid/bases for titration and all that junk.
One of the questions in this year's HSC was about safety and risks in neutralisation reactions etc...

 

[spice girl]

Originally posted by fashionista
so if i sed in my discussion that my results may be inaccurate due to the presence of ascorbic or phosphoric acid in addition to the citric would i be marked down?

umm prolly not. it's wot u have to say. they won't expect u to then measure phosphate conc or something silly...

Originally posted by fashionista if i react a fizzy drink with NaOH will both the citric acid and the other present acid react? and then if they do how will i do the calculations for two acids reacting with the NaOH if I am to find out the concentrations of both of them

if you heat and boil the drink for a while the CO2 should all be gone. so you can titrate it after boiling, and one without boiling, then you can get both.

and Ziff, your friend's backyard indicator may have been a bit dodgy, cos plant juice contains more than indicator. there could have been buffering agents that would interfere with the endpoint.

 

[fashionista]

tank u evry1!!! i'll let u noe how ur fabulous guidance has done me good (that english sounded soo rong) in a couple of weeks)