Chemistry SPA
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i am having a spa assessment tml on acis,bases and salt. Do you guys have some tips for me? I think i am not doing well for it.
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What is about? Titration, Report writing, ???
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erm tiltration shld be coming out.
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over alr lor.
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Different schools have different timings for SPAs, so yours may be over, but he's isn't.
Just be careful not to break anything, seriously. The burette and pipette are like your lifelines, if you break them, one level down.
By the way, learn to do smart cheating. If you obtained a freak result while doing all your titrations (something that is super extraordinary, different from the other results, esp during your practices), DON'T WASTE TIME REDOING!!! Just change the results to fix your freak result, and continue. So have a basic idea of WHAT RESULT YOU'RE GOING TO GET (during SPA practice you should have done that). Don't depend on the readings.
Lastly, don't cheat until damn obvious. Where all your results are the same... then gone case liao.
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what can come out beside tiltrations? help me thx.
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Are you Secondary 3? And your teacher should have told you what's coming out. What have you been practising in the labs all these time?
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I m taking O(s) now. First spa - over a year ago.
Well, your first SPA comes at a very early date though.
Acid bases and salt can come out in lots of things -
test for anions and cations. (QA table. Like Ammonia gas produced when Ammonium is mixed with aqueous ammonia and heated or white precipitate produced and you will have to derive what is the cation. Calcum does not react with aq ammonia vs zinc (both Aq ammonia and naoh in excess) ect ect ect.
Salt could be to produce Cuso4 salt. Then teachers will see how you filter (ususally an insoluble salt and a soluble Cus04) , heat up ect.
Always wear your goggles when you are heating/ lighting up a fire.
Air hole, close. then open up. (visible flame when open up) due to incomplete combustion.
Acid and bases could be titration. - Look at the tip of the burette and pipette. - make sure there are no air bubbles. if there are, empty alittle into the (bucket/ beaker)
Read at eye level.
Do drip by drip when you are near the neutralisation reading for titration. carefully release the burette.
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ya i am. my teacher jus sux.
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SPA 1, IIRC, is titration. Danger is breaking things.
Then the second one is rate of reaction. This is super easy.
Then the last one is writing a step-by-step procedure how to carry out an experiment. Danger is the topic coming out. You can memorise all the formats and if something weird comes out, then you're still dead.
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This is what i can think about. there might still be more.
Be sure to remember the colour of indicatiors.
Litmus indicator - Acid (red), Alkali (blue)
phenolphtalein - Acid (colourless), Alkali (pink) note: the pink will be very light in the experiment, just end and take your reading when you see it's slightly pink. - Compare with the white tile.
Methyl orange - Acid (red) alkali (yellow)
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Originally posted by Garrick_3658:
All those only for practice what. Since when got come out as SPA.
SPA 1, IIRC, is titration. Danger is breaking things.
Then the second one is rate of reaction. This is super easy.
Then the last one is writing a step-by-step procedure how to carry out an experiment. Danger is the topic coming out. You can memorise all the formats and if something weird comes out, then you're still dead.
Not all SPAs are titration. There was one school that i enquired on last year who had test for Cat ion and anions instead of titrations.
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ok. is there any diagrams on the question paper? i know there is procedure.
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Originally posted by kenn3th:
This is what i can think about. there might still be more.
Be sure to remember the colour of indicatiors.
Litmus indicator - Acid (red), Alkali (blue)
phenolphtalein - Acid (colourless), Alkali (pink) note: the pink will be very light in the experiment, just end and take your reading when you see it's slightly pink. - Compare with the white tile.
Methyl orange - Acid (red) alkali (yellow)
I always did the other way round. Isn't it easier?
Put alkali in pipette, transfer to flask, add phenolphthalein, observe pink colour. Add acid from burette, for 20 cm^3 then drip by drip, until ONE DRIP will turn the solution colourless. Compare against white tile for any pink colours left.
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Originally posted by Garrick_3658:
I always did the other way round. Isn't it easier?
Put alkali in pipette, transfer to flask, add phenolphthalein, observe pink colour. Add acid from burette, for 20 cm^3 then drip by drip, until ONE DRIP will turn the solution colourless. Compare against white tile for any pink colours left.
must read the question. some say, put indicator at which solution.
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Originally posted by Darkiish:
ok. is there any diagrams on the question paper? i know there is procedure.
No. Procedure will suffice.
Don't worry, it will be something nearly THE SAME as what you did for the practice all the time.
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memorise the anions and cations table. As well as the test for gases.
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Originally posted by Darkiish:
ok. is there any diagrams on the question paper? i know there is procedure.
if you are lucky, there will be a diagram to show you how to set up. (general)
like pipette on retrot stand ect.
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Originally posted by Garrick_3658:
No. Procedure will suffice.
Don't worry, it will be something nearly THE SAME as what you did for the practice all the time.
the hint would be, if the teacher emphasised on which ever pratical - like titration 3 times. then you will roughly know.
Have you done your Mock spa?
If you have, pls read through the comments and see there should be different marks like
S1 - 1 mark
S2 - 0
ect.
so read from there and you will know your strengths and weaknesses.
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ah yes,observation is write color of solution initially and finally,whether it dissolves in excess,whether got any gas appear. Conclusion is write what u think is produced. like the soultion is sth sth and sth sth gas is evolved
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what is experimental errors and precautions?
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Manage your time well, dont worry about washing up, you will be given time at the end of the SPA, (outside doing time).
Rinse apparatus with tap water then distilled, if you are the 2nd batch.
the teacher (your school) will tell you that it's a new batch and you do not need to wash.
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Originally posted by Darkiish:
what is experimental errors and precautions?
You cannot write errors that you can prevent.
Write errors like:
acidic carbondioxide reacts with the alkali, thus reducing the concentration of alkali and hence resulting in lesser volume of 1mol/dm3 (eg) of hcl (or anyother acid) reacting with the alkali.
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precautions - if you are using a burnson burner (unlikely) precaution is, close air hole, wear goggles then light. This is to prevent flash back of flames.
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if its the experiment on tiltrations, what is the possible answers for precaution and error made.