SAC 1

[Studyinghard]

First SAC is just around the corner and was hoping to get some resources regarding this SAC as it is quite a popular one.

We did a gravimetric and a back titration with fertiliser.

We took the fertiliser and dissolved. Then we added HCL and boiled it. We then added barium chloride so that a precipitate of barium sulfate would form.

We also did a back titration when we put ammonium ions and dissolved it. Then added Sodium hydroxide to form ammonia gas and water. then we titrated that with HCL and average titres were done.

Did any schools out there do SACS like these or are there any questions that are available that could come up or just any tips in general I should know about.

Thanks

[superflya]

general error questions always come up i.e what would happen if the volumetric flask was rinsed with water blah blah.. MUST KNOW THIS STUFF.

[physics]

we had the exact same thing and there wasn't any theory in our one... just have to solve questions relating to gravimetric and volumetric so jjust keep doing practise questions..preactise makes perfect.

[xD_aQt]

^ the sac you did was all equations and no written theory ? ? ? wow ...

[superflya]

^ the sac you did was all equations and no written theory ? ? ? wow ...

impossible, lies anna?

[physics]

^ the sac you did was all equations and no written theory ? ? ? wow ...

impossible, lies anna?

no i am not D:

the only thing where actually sentences were required was the observvations and conclusions it wqas a prac write up which is our sac one

[hhland]

Can anyone upload practise sacs or just past sacs?

[Transcendent]

We also did a back titration when we put ammonium ions and dissolved it. Then added Sodium hydroxide to form ammonia gas and water. then we titrated that with HCL and average titres were done.

Melbourne High is doing that for their first chem sac i believe.

[Studyinghard]

general error questions always come up i.e what would happen if the volumetric flask was rinsed with water blah blah.. MUST KNOW THIS STUFF.

Do you know anywhere where I can get all these error questions because there arent much in the textbook.

we had the exact same thing and there wasn't any theory in our one... just have to solve questions relating to gravimetric and volumetric so jjust keep doing practise questions..preactise makes perfect.

wow how I wish this was my SAC

[naved_s9994]

I believe most if not all schools do this (Or something VERY similar)... Its part of the curriculum.

[Twenty10]

You must know possible sources of errors. KNow as many as possible not just one or two. This is where i stuffed up in SAC 1.

[kyzoo]

Hahaha just had gravimetric analysis SAC today. Did prac today, and have to question stuff on Monday. And we get no access to notes or textbooks 0.o.

[stonecold]

errors is easy...

in gravimetric stuff like:
-loss of ions through transfer
-other ions could have reacted to form the precipitate
-some of the precipitate may have been lost in the filtrate
-the reaction was not complete
-the precipitate was not dried to constant mass

like someone else said, blah, blah, blah. and hence why these techniques are stupid and aren't even used anymore.

for volumetric it's important you know what will happen if:
-the burette, pipette and volumetric flask are rinsed with the wrong solution
-errors caused by misreading of the miniscus on calibration marks
-major source of error being the subjective observation of the end point according to the colour change.

pretty simple stuff....

[Twenty10]

you may also have to explain the significance of errors.

[Studyinghard]

Okay so I'm a tad worried because I have gone through all the errors for both gravimetric and volumetric and am pretty confident about doing the calculations . SO how is it possible for a SAC to be just that ? It doesnt even seem that much. Like all that put together would only be like 3 questions at best.