Titration (2 Viewers)

[sunsettah]

Don't stuff up the concentrations. Is it pre- set for you? Like the chemicals? Or do you have to work them out yourself?

 

[hena_xox]

yea my prac went great i got it all right but i lost marks only coz i wasnt wearing safety glasses and was using acid.. thats all i went wrong...

i have these worksheets that have the my exact assessmenttitration pracon it if u want 2 me scan it and send it 2 u?its really helpful.

 

[wantingtoknow]

Yes please, thanks ^^

@ sunsettah: The standard solution? We have to make it ourselves

 

[sunsettah]

mmkaaay.

Just.. yeah.. make sure you account for the pH of the acid n base.

Like don't use a strong base on something weak like citric acid, n all that jazz.


Well I've not done them as a prac in class.

We went to a CSU Chemistry day, and did it there =]

That covered the syllabus point, so I don't think we'll do it again.

Yay.

 

[eriito]

yea my prac went great i got it all right but i lost marks only coz i wasnt wearing safety glasses and was using acid.. thats all i went wrong...

i have these worksheets that have the my exact assessmenttitration pracon it if u want 2 me scan it and send it 2 u?its really helpful.

yes please. msg-ed you

 

[eriito]

I usually only complete two titrations - one test run (let the solution in the burette flow out quickly and gain a rough idea of the equivalence point), and one proper run (I'm pretty lazy when it comes to titrations, so I put all my time and effort into gaining just the one result and using that as my average, ahah).

My pet hates regarding titration:

- acid/base on the sides of the conical flask (always wash it down with distilled water)
- bubbles in the burette and/or pipette (give it a good tap, or refill)
- not using enough indicator (textbooks say to put around 3-5 drops, put 10 times that amount)
- solution turns into the equivalence colour, but then changes back to its original colour after three seconds or so (this is actually a good thing, and I usually take this reading as my final result)

Hope this helps,
Good luck in your exam!

hmmm... 10 times 3-5 drops. LOL

 

[hena_xox]

if any 1 wants the worksheets just tell me ur email addy coz i dont no how 2 add attachments on here.... i also have the calculations for the prac if u want them aswell so just let me no!!

 

[marcquelle]

marcquellestudieshard@hotmail.com

 

[wantingtoknow]

hmmm... 10 times 3-5 drops. LOL

I KNOW, LOL..that's like 1/4 of the bottle of indicator.

 

[jet]

doesn't the one that you are measuring go in the pipette
if you know the amount of one, you put that in the burette because then you can get a reading from the pipette on to how much you have used to get the indicator colour right

I believe you have confused the pipette and the burette. You put the solution of unknown concentration in the pipette, so you can control the volume of it needed.

You put the solution of known concentration into the burette, and measure how much of that you use to 'neutralise' the unknown.


To the OP, if you have a choice of indicators, choose wisely:
-Strong Acid, Strong base -> neutral salt pH ~7 (Bromothymol Blue)
-Srong Acid, Weak base -> Acidic Salt pH acidic and could vary (Methyl Orange)
-Weak Acid, Strong Base -> Basic Salt pH basic and could vary (Phenolphthalein)

These are the most common indicators you would use. There may be others instead. Just make sure you know the basic ranges of the common ones.

 

[brenton1987]

You put the solution of known concentration into the burette, and measure how much of that you use to 'neutralise' the unknown

It is best to use acid in the burette because strong bases can affect the functioning of the teflon tap.

 

[x.Exhaust.x]

I believe you have confused the pipette and the burette. You put the solution of unknown concentration in the pipette, so you can control the volume of it needed.

Lol I'm certain it's the other way around jetblack. The known concentration (known as the primary standard solution e.g. Na2CO3 mixed with distilled water) goes into the pipette. The HCl (secondary standard) goes into the burette.

 

[Live Laugh Love]

If you're using a funnel, make sure you take it out when adding the Primary Standard into the burette, coz our teacher said thats the kind of thing she'd deduct marks for!

 

[xxstef]

Does it matter where you put the base and acid? :S

we got taught to put bases in pipette and acid in burette, coz if you put bases in the burette, it'll react(?) with the glass (silicon stuff) that makes the burette and cause little scratches, so it won't be accurate anymore.