Errors!

[cindyy]

sigh the past 2 hours i've been confused with this titre thing.................

So i was going through my chem stuff, and i found this table table that my teacher had done with me about errors! haha oopsy  

Burette--->Water: Solution in burette is diluted, more titre required, more volume, lower concentration
                          Concentration in flask is higher, more mols, higher concentration.

Pipette--->Water: number of mols in the flask will be less, titre will be less, concentration will be higher
                          number of mols in the flask will be less, concentration of the flask will be less.

Flask --->Solution:        mols in the flask will increase, titre will increase, concentration will decrease
(that goes in the flask): mols in the flask will increase, concentration in the flask will increase.

Hope that helped a bit, it helped me

Change of plans for tomorrow.  Ditching study and instead undertaking covert operation to break into my school and steal 1 x Chemistry Exam and 1 x Biology Exam.  Feel free to join me.

COUNT ME IN!!!!!

[chansthename]

Stonecold, I don't think that your explanation is completely correct because you are not using all of the solution in the burette, and so the amount of mole in the burette does not affect the titration as such. It is the concentration of solution in the pipette that actually affects the results.

I disagree, my working is on the first page which agrees with stonecold if you want to see my reasoning.

The main thing is that a pipette (using a scenario) takes 20ml (in this example)

so you are trying to get 20mL of NaOH into your pipette however because there are water molecules you can only fit 19.85 mL. giving you less HCl needed for the titre.


BTW, can you scan a copy for me stonecold (the 2010 vcaa exam of course)

[m@tty]

It is still 20 ml of NaCl. Remember that there is always LOTS of water in sodium chloride solution(salt water..); the Na and Cl are just ions floating around in the solution. When you take an aliquot of 'water and NaCl' it is really just a more dilute NaCl solution. Less mole, same volume => less concentrated.

[chansthename]

less concentrated.

which means less HCl need for the titration.

And what I meant was only 19.85 of the original NaOH solution fits in the pipette.