Titration results (1 Viewer)

[Zoltan]

Oh man I feel like the biggest nerd asking this, but we did a titration prac as an assessment the other day and it's driving me insane. I thought my method and equipment and calculations and everything were fine, everyone who looked at them thought they were fine, but my results were a bit weird... the vinegar we were supposed to be finding out the concentration of was 0.7 molar (or something) while the NaOH was 0.1 molar. Is it acceptable for vinegar to be 7 times more concentrated than NaOH, or have I fucked up? If I know, at least I can stop obsessing (hopefully )

 

[tennille]

Do you remember what you did for your calculations?

Did you put the acid in the burette?

 

[Zoltan]

yeah the acid was in the burette, as far as I know my calculations were fine.

 

[Dreamerish*~]

CH₃COOH + NaOH --> NaCH₃COO + H₂O

molar ratios are 1:1.

hmm, how many volumes of each did you use?

 

[tennille]

So you found the volume of acid used. There is a 1:1 ratio of NaOH with CH3COOH, so the amount of moles are equal. Then you divide the amount of moles by the volume and that's your molarity of CH3COOH. If you diluted the substance about 10 times then you multiply it by 10.

I think that answer is about right. I did that titration recently, and I got about 0.71 (the real answer was 0.75ish). But it depends on how concentrated the acid is.

 

[mitochondria]

If that's what you got then that's what you got I must add that it is indeed a bit odd to have a 0.75M acid titrating against a 0.1M base because you will only need about 3.2mL for 25mL of NaOH Care to post your results up?

 

[tennille]

If that's what you got then that's what you got I must add that it is indeed a bit odd to have a 0.75M acid titrating against a 0.1M base because you will only need about 3.2mL for 25mL of NaOH Care to post your results up?

They may have diluted it.

 

[Dreamerish*~]

If that's what you got then that's what you got I must add that it is indeed a bit odd to have a 0.75M acid titrating against a 0.1M base because you will only need about 3.2mL for 25mL of NaOH Care to post your results up?

mito is back!!!!!!

he-who-almost-never-posts

 

[Zoltan]

Um I'll see if I can remember them... I had 25 ml NaOH in the flask and ended up using about 3-4 ml vinegar to titrate it. The NaOH was 0.108 M (definately) and the result I got for the vinegar was 0.72 M. I just wondered if that was possible... if it is, then I might be ok

 

[tennille]

Say it was 3.5mL. Then the amount of moles of NaOH is 0.108*0.025= 0.0027. Then CH3COOH is 0.0027 moles. You used 3.5mL of CH3COOH, therefore the molarity of CH3COOH is 0.0027/0.0035 = 0.77mol/L

 

[pseudobubble]

Um I'll see if I can remember them... I had 25 ml NaOH in the flask and ended up using about 3-4 ml vinegar to titrate it. The NaOH was 0.108 M (definately) and the result I got for the vinegar was 0.72 M. I just wondered if that was possible... if it is, then I might be ok

I think you got it right ^^ besides, the volume of CH3COOH you used agrees with what mitochondria has predicted, so it must be right ^^

The Acidic Environment is my favourite topic ^^

I say, do not panic =) Keep the good work up!


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How do you do the subscript thing? (As-many-as-the-number-of-molecules-of-water-you-can-find-on-earth thanks in advance) ^^

 

[Jumbo Cactuar]

mito is back!!!!!!

he-who-almost-never-posts

I guess Friday night served for a bit of good then!

 

[mitochondria]

I can remember being dizzy

 

[Jumbo Cactuar]

I can remember wanting to throw up desperately. That purple stuff was vile, and I don't think it mixed with all those free meat pies from the Dean

 

[mitochondria]

*frown at the thought of that.. atrocious ultraviolet thing*

that was better than the nylon thing though (this is very much related to chemistry *nods*) skim milk + raspberry + homebrand lemonade + some sort of unknown vanilla scented alkanol..

I didn't know you can make a polymer like that

 

[xiao1985]

*frown at the thought of that.. atrocious ultraviolet thing*

that was better than the nylon thing though (this is very much related to chemistry *nods*) skim milk + raspberry + homebrand lemonade + some sort of unknown vanilla scented alkanol..

I didn't know you can make a polymer like that

can u do taht?! is condensation polymerisation of...
alkanol with~~~
lactic acid?!

 

[mitochondria]

*waves at xiaoie*

yes O____o.. you should try it! It looked terrible.. I called it nylon because it reminded me of the polymerisation prac we did in first year, just like nylon O____o...